Ecology & IPM Study Material PDF

1 ACHARYA N G RANGA AGRICULTURAL UNIVERSITY Rajendranagar, Hyderabad – 500 030 Study Material for Insect Ecology and Integrated Pest Management Course No. Ento.231 (2+1) (2011-12) Editors...

1 ACHARYA N G RANGA AGRICULTURAL UNIVERSITY Rajendranagar, Hyderabad – 500 030 Study Material for Insect Ecology and Integrated Pest Management Course No. Ento.231 (2+1) (2011-12) Editors G Raghavaiah Professor & Head Department of Entomology Agricultural College, Bapatla T Ramesh Babu Professor & Head Department of Entomology College of Agriculture Rajendranagar, Hyderabad Co-Editors K Hari Prasad S R KoteswaraRao P V Krishnayya K Manjula P Seetha Ramu K Sridevi S Upendhar  2 Objectives and Lecture Out-lines Genera Objective: To impart knowledge to the students on ecology of insects and various insect and non-insect pest management Specific Objectives : Theory: By the end of the course, the students will be able to 1) Know the influence of ecological factors on insect development and distribution 2) Understand the components of integrated pest management 3) Know the classification of insecticides and their use in pest management 4) Understand the mass multiplication techniques of major bio-agents 5) Understand about non-insect pests and their management Practical: By the end of the practical exercises, the student will be able to 1) Know sampling techniques for estimation of insect population 2) Know about light traps, pheromone traps and insecticides in pest management 3) Identify the biological agents 4) know insecticide formulations and dosage calculation 5) Acquaint with mass multiplication of bio-agents 6) Identify different nematodes, mites and other non insect pests  3 Theory Lecture Outlines Lecture Content Between No Pages 1 Ecology – introduction - autecology and synecology – population, 8-9 community - importance of insect ecological studies in integrated pest management (IPM) - environment and its components – soil, water, air and biota. 2 Abiotic factors - temperature-its effect on the development, fecundity 10-14 distribution, dispersal and movement of insects - adaptations of insects to temperature - thermal constant Moisture- adaptation of insects to conserve moisture. - humidity- its effect on development, fecundity and colour of body - rainfall - its effect on emergence, movement and oviposition of insects. 3 Light – phototaxis - photoperiodism - its effect on growth, moulting 15-18 activity or behaviour, oviposition and pigmentation - use of light as a factor of insect control; Atmospheric pressure and its effect on behavior. Air currents - effect on dispersal of insects – edaphic factors – water currents. Biotic factors – food - classification of insects according to nutritional requirements - other organisms - inter and intra specific associations - beneficial and harmful associations of parasitoids based on site of attack, stage of host, duration of attack, degree of parasitism and food habits. 4 Concept of balance of life – biotic potential and environmental 19-23 resistance – normal coefficient of destruction - factors contributing to increase or decrease of population - causes for outbreak of pests in agro-ecosystem – explanation for these causes. 5 Pest surveillance – definition - importance in IPM – advantages - 24-26 components of pest surveillance - pest forecasting - types of forecasting (short term and long term forecasting and their advantages) – insect pests – definitions of negligible, minor and major pests; Different categories of pests – regular, occasional, seasonal, persistent, sporadic, epidemic and endemic pests with examples. 6 IPM – introduction - importance – evolution of IPM, collapse of 27-32 control systems, patterns of crop protection and environmental contamination – concepts and principles of IPM – Economic Threshold Level (ETL) – Economic Injury Level (EIL) and General Equilibrium Position (GEP) – tools or components of IPM – practices, scope and limitations of IPM. 7 Host-plant resistance- principles of host plant resistance – ecological 33-40 resistance – phenological asynchrony, induced resistance and escape – genetic resistance – mono, oligo and polygenic resistance –  4 major gene resistance (vertical/specific/qualitative) and minor gene resistance (horizontal/nonspecific/quantitative) – host-plant selection process- host habitat finding, host finding, host recognition, host acceptance, host suitability- Mechnisms of Genetic resistance- non- preference(antixenosis), antibiosis and tolerance – transgenic plants. 8 Cultural control- normal cultural practices which incidentally control 41-44 the pests and agronomic practices recommended specifically against the pests with examples; Mechanical control- different mechanical methods of pest control with examples. 9 Physical control – use of inert carriers against stored product insects 45-48 - steam sterilization – solarization - solar radiation - light traps - flame throwers etc.; Legislative measures - importance of quarantine - examples of exotic pests - different legislative measures enforced in different countries including India. 10 Biological control - types of biological control – introduction , 49-54 augmentation and conservation – parasite – parasitoid - parasitism - grouping of parasites based on nature of host, stage of host, site of parasitisation, duration of attack, degree of parasitisation and food habits – Kinds of parasitism – qualities/attributes of an effective parasitoid to be successful one. Biological control - Predators – predatism – qualities of insect predator – differences between predator and parasite 11 Microbial control - Bacteria, viruses, fungi, nematodes and protozoa - 55-58 important species of micro organisms against major pests for incorporation in IPM- entomopathogenic nematodes – important species - mode of infectivity and examples; - advantages and disadvantages of biological control. 12 Beneficial insects - Important species of pollinators - caprification – 59-61 pollination syndromes –factors that affect pollination - weed killers – success stories - scavengers - their importance. 13 Chemical control - importance and ideal properties of insecticide - 62-69 classification of insecticides based on origin, mode of entry, mode of action and toxicity - toxicity evaluation of insecticides - acute or chronic toxicities, oral and dermal toxicities - LC50 (Lethal Concentration), LD50 (Lethal Dose), ED50 (Effective Dose), LT50 ((Lethal time), KD50 (Knockdown Dose) and KT50 (Knock Down Time) – bioassay methods. Formulations of insecticides - dusts, granules, wettable powders, water dispersible granules, solutions, emulsifiable concentrates, suspension concentrates, concentrated insecticide liquids, fumigants, aerosols, baits and mixtures of active ingredients. 14 Inorganic insecticides - arsenic Compounds - fluorine and sulphur; 70-74  5 Plant derived insecticides - neem based products - different commercial formulations containing azadirachtin, neem seed kernel extract, neem cake and their uses – nicotine, rotenone, plumbagin and pyrethrum – source – properties and uses. 15 Synthetic organic insecticides – chlorinated hydrocarbons – Dichloro 75-80 Diphenyl Trichloroethane (DDT) and Hexa choloro Cyclo Hexane (HCH). Cyclodiens - aldrin, dieldrin, heptachlor and endosulfan - toxicity and mode of action. Organo phosphates - systemic, non-systemic and translaminar action of insecticides with examples – brief mode of action – toxicity, formulations and uses of malathion, methyl parathion, diazinon,dichlorvos, fenitrothion,quinalphos, phosalone, chlorpyriphos, phosphomidon, monocrotophos, methyl demeton, dimethoate, triazophos, profenophos, acephate and phorate. Carbamates - mode of action – toxicity, formulations and uses of carbaryl, propoxur, carbofuran, aldicarb and methomyl - Insecticides with nematicidal and acaricidal properties. 16 Synthetic pyrethroids - brief mode of action – toxicity, formulations 81-85 and uses of allethrin, resmethrin, bioresmethrin, bioallethrin, fenvalerate, permethrin, deltamethrin, cypermethrin, lambda cyhalothrin, cyfluthrin, fenpropathrin, flucythrinate, fluvalinate and fenfluthrin. Insecticides of other groups - fixed oils; Novel insecticides – nicotinoid insecticides - brief mode of action – toxicity, formulations and uses of imidacloprid, acetamiprid, thiamethoxam and clothianidin; Phenyl pyrazoles - brief mode of action – toxicity, formulations and uses of fipronil. 17 Macro cyclic lactones – spinosyns - brief mode of action – toxicity, 86-89 formulations and uses of spinosad; Avermectins –brief mode of action – toxicity, formulations and uses of abamectin and emamectin benzoate; Oxadaizines – brief mode of action – toxicity, formulations and uses of indoxacarb; Thioureas - brief mode of action – toxicity, formulations and uses of diafenthiuron; Pyridine azomethines - brief mode of action – toxicity, formulations and uses of pymetrozine; Pyrroles - brief mode of action – toxicity, formulations and uses of chlorfenapyr. Formamidines – brief mode of action – toxicity, formulations and uses of chlordimeform and amitraz; Ketoenols - brief mode of action – toxicity, formulations and uses of spirotetramat, spiromesifen and spirodiclofen.Diamides brief mode of action – toxicity, formulations and uses of Chlorantraniliprole, cyantraniliprole and flubendiamide  6 18 Chitin synthesis inhibitors – brief mode of action - toxicity, 90-100 formulations and uses of diflubenzuron, flufenoxuron, chlorfluazuron, triflumuron, teflubenzuron, flufenuron, novaluron and buprofezin;Juvenile hormone (JH) mimics – brief mode of action - toxicity, formulations and uses of Juvabione, methoprene , hydroprene, kinoprene pyriproxyfen and fenoxycarb- Anti JH or precocenes, Ecdysone agonists - brief mode of action – toxicity, formulations and ,uses of methoxyfenozide ,halofenozide and tebufenozide. Recent methods of pets control- repellants (physical and chemical) and antifeedants - importance of antifeedants and limitations of their use – attractants - sex pheromones - list of synthetic sex pheromones - use in IPM - Insect hormones – gamma irradiation – genetic control – sterile male technique. 19 Rodenticides – zinc phosphide, aluminum phosphide, bromodilone; 101-103 Acaricides- sulphur, dicofol, tetradifon and propargite; Fumigants - aluminum phosphide 20 Application techniques of spray fluids - high volume, low and ultra low 104-115 volume sprays - phytotoxic effects of insecticides - advantages and limitations of chemical control – safe use of pesticides. Symptoms of poisoning - first aid and antidotes for important groups of insecticides; Insecticide resistance-insect resurgence-insecticide residues – importance - Maximum Residue Limits (MRL) – Average Daily Intake (ADI) – waiting periods – safety periods - Insecticides Act 1968 – important provisions. 21 History of nematology- economic importance in agriculture- 116-123 classification of nematihelmanthes - General characters of plant parasitic nematodes. 22 Nematology- Different functional systems of nematodes. 124-130 23 Nematology- Biology and ecology of nematodes- types of parasitism- 131-135 complex diseases caused by nematodes 24 Nematology- Different types of nematodes 136-142 25 Nematology- Integrated nematode management-Host plant 143-145 resistance-cultural- Mechanical methods 26 Nematology- Integrated nematode management-Physical- Biological- 146-148 Quarantine-chemical methods 27 Mites- Importance - morphology and biology of mites. 149-151 28 Mites- Classification- characters of important families tetranychidae- 152-153 host range. 29 Mites- Classification- characters of important families, tenuipalpidae, 154-156 tarsonimidae and eriophyidae- host range.  7 30 Rodents- Important major rodent sps.- Nature of damage- 157-160 management 31 Other non insect pests- important bird, crabs, snails and animal pest 161-163 damage to crops- management strategies. 32 House hold and live stock insect pests- Important pests of domestic 164-167 and veterinary importance and their management. PRACTICALS: 1. Study of distribution patterns of insects in crop ecosystems 2. Sampling techniques for the estimation of insect population and damage 3. Pest surveillance through light traps, pheromone traps and forecasting of pest incidence 4. Calculation of doses/ concentrations of different insecticidal formulations 5. Acquaintance of insecticide formulations 6. Compatibility of pesticides with other agrochemicals and phytotoxicity of insecticides 7. Acquaintance of mass multiplication techniques of important predators – Cheilomenes, Chrysoperla and Cryptolaemus 8. Acquaintance of mass multiplication techniques of important parasitoids – egg, larval and pupal parasitoids 9. Acquaintance of mass multiplication techniques of important entamopathogenic fungi 10. Acquaintance of mass multiplication techniques of Nuclear Polyhedrosis Virus (NPV) 11. Study of insect pollinators, weed killers and scavengers 12. Extraction of nematodes from soil and roots-preparation of temporary and permanent slides 13. Identification of different types of nematodes 14. Identification of different mite species 15. Identification of different non-insect pests-birds, rodents, crabs and snails 16. Identification of different non-insect pests-house hold and veterinary insect pests Note: Submission of well maintained insect specimens during the final practical examination is compulsory REFERENCES: Dhaliwal GS and Ramesh Arora 2001. Integrated pest management: Concepts and approaches, Kalyani Publishers Ludhiana Gautam,R.D 2008 Biological Pest Suppression. Westville publishing House New Delhi Metcalf RL and Luckman WH 1982. Introduction to insect pest management. Wiley inter science publishing, New York. Nair KK , Anantha Krishnan TN and BV David 1976. General and applied entomology, Tata Mc Graw Hill publishing co. Ltd, New Delhi Larry P Pedigo 1991. Entomology and pest management, Prentice Hall of India Private Ltd., New Delhi Upadhyaya K.P and Kusum Dwivedi.1997. A Text Book of Plant Nematology Aman Publishing House, Meerut Venyugopala Rao,N., Umamaheswari,T., Rajendraprasad,P.Naidu,V.G and Savithri,P.2004. Integrated Insect Pest Management. Agrobios (India) Limited,Jodhpur Yazdani,S.S and Agarwal,M.L.1979. Elements of Insect Ecology. Narosa Publishing House,New Delhi  8 LECTURE NO. 1 INSECT ECOLOGY The word ecology is the modified form of ‘Oekologie’ derived from the Greek ‘Oikos’, meaning ‘Home’ and ‘Logos’ meaning ‘Discourse’ introduced by Reiter in 1869 and later anglicized to ‘Ecology’. Ecology is a multidisciplinary subject and derives support from other sciences. Individual organisms of the same species live together as a ‘Population’. Population can be defined as ‘a group of individuals or a species occurring in a given area or locality at a specific time’. Populations of different species live together and form a ‘Community’, meaning ‘all populations in the area at a specific time’. The community is influenced by its physical environment. The complex system of biotic and abiotic factors constitutes an ‘Ecosystem’. Whereas the crops, insects, other animals and the physical abiotic factors together constitute an ‘Agro-ecosystem’. Ecology is ‘the science of inter-relations between living organisms and their environment including both the physical and the biotic environments and emphasizing inter species and intra species relations’ (Allee, 1949). Odum (1953) defined ecology as ‘the study of the structure and functions of nature (or Environmental biology)’. Ecology is divided mainly into ‘Autecology’ and ‘Synecology’. Autecology is the study of individual organisms or an individual species in relation to the environment while Synecology is the study of the group or groups of organisms associated in a community in the same environment i.e., in relation to various other species living in the same environment. Importance of Ecology in Pest Management: Indiscriminate uses of pesticides lead to a regular resurgence of pests due to the fact that the natural enemies get killed. The increase in pest population is also due to the interference of man by monoculture, using high yielding and susceptible varieties, giving more number of irrigations, use of high nitrogenous fertilizers etc. Because of which the balance of life in nature gets upset and the pest appears in severe form every year. The importance of ecology was then felt and integrated approaches in pest management are now made to avoid the violent fluctuations in pest populations. Ecological studies assist pest control programmes by explaining pest problems and suggesting alternate ways of combating insects. The outbreaks of the pests can also be predicted. The ecological studies investigate the causes for the changes in population number and the mechanism of natural control. The key mortality factors in a natural population help to integrate the various methods of control, without disturbing the balance of nature. The pest surveillance programmes form a part of ecology. Forecasting of the possible attack by different pests can be done and accordingly the control measures can be initiated in time. Suitable chemicals can be selected depending on the presence or absence of natural enemies. As such ecological studies form a basic part of the approach to the integrated pest management (IPM).  9 In nature the living organism and the non-living substances of environment interact to form ecosystem. The environmental complex constitute (1) Biotic factors known as ‘Density dependent factors’ include a) Food and b) Other organism and 2) Abiotic factors known as ‘Density independent factors’ comprise a) Temperature b) Humidity c) Rainfall d) Light e) Air f) Water g) Soil etc.  10 LECTURE NO. 2 ABIOTIC FACTORS –TEMPERATURE, MOISTURE, RAINFALL, LIGHT & OTHERS Effect of Abiotic Factors on Insect Population a) Temperature This is the most important physical factor which determines the duration of the various stages in the insect life cycle and consequently the number of generations during any period of time. It acts on insects in two fold manner 1. By acting directly on the survival and development which determine the abundance of a pest 2. Indirectly through food and other environmental factors such as moisture, rainfall, wind etc. Depending on the maintenance of body temperature, animal kingdom is divided into 1) Warm Blooded Animals (Homeothermic): These animals maintain a constant body temperature within certain narrow limits irrespective of the temperature variations in the external environment. These are also called as ‘Endothermic animals’ because they rely on internal source of heat to compensate the lost heat to cooler surroundings. Eg. Mammals 2) Cold Blooded Animals (Poikilothermic) : These animals are not capable of maintaining constant body temperature.They do not have internal mechanism of temperature regulation and therefore their body temperature varies with that of the surroundings. These are also called as ‘Ectothermic animals’ as they depend upon the environment than the metabolic heat to raise their body temperature. Eg. Insects 3) Socio-homeothermic Animals: These organisms maintain their body temperature slightly above the atmospheric temperature and are able to air condition their nests. They maintain their own temperature inside their colony irrespective of the temperature outside. Eg. Honey bees Temperature regulates the development, fecundity, feeding, movement and dispersal and distribution of insects. Development In general insects grow more rapidly in warm weather than in cold weather. A given species of insects is active within certain limits of temperature. In general the optimum temperature for the normal development of insects is 10 to 35°C and is known as ‘Zone Of Optimum or Normal Development’.  11 Depending on the development of insects at different temperature levels, the temperature is divided into different zones as follows: 600C - Maximum Fatal Temperature Zone of Fatal High Temperatur 500C - - Zone of Inactivity due to High Temperature 350C - Maximum Effective Temperature (Threshold of Developmewnt), Upper vital limit Zone of Optimum/Normal/Effective Temperature 100C - Minimum Effective Temperature (Threshold of Developmewnt), Developpmental zero Zone of Inactivity due to Low Temperature -50C Zone of Fatal Low Temperature -140C - Minimum Fatal Temperature 1. Zone of Effective Temperature (10 to 35°C) in which some development takes place, the limits of which are known as a) Minimum effective temperature or threshold of development (10 to - 5°C): at which on descending scale development ceases and on ascending scale the development starts. The growth of poikilothermic animals is arrested at 0°C and this temperature is called as ‘Developmental zero’ b) Maximum effective temperature (35 to 50°C): The upper vital limit at which on ascending scale the development ceases and on descending scale the development begins. 2. Temperature Zones of Inactivity The temperature immediately above and below the zone of effective temperature are the ‘Zones of inactivity’. In these zones the insect is alive but there will not be any development and they can recover if removed to favourable temperature.  12 3. Fatal Zones of Temperature Beyond the zones of inactivity are the ‘Fatal high (50 to 60°C)’ and ‘Fatal low (-5 to -14°C)’ temperature zones, indicating ‘Minimum fatal (-14°C)’ and ‘Maximum fatal (60°C)’. Death at fatal high temperature is due to loss of water, coagulation of proteins, high metabolic rate, accumulation of toxins and affected enzymatic activity. Death at fatal low temperature is due to low enzymatic activity, low metabolic rate and freezing of body fluids. Some insects do not freeze but survive even under 0°C as their body fluids contain polyols like glycerols. If an insect is given a choice to move along a temperature gradient it prefers a narrow limit of temperature known as the ‘Temperature preferendum’ or ‘Preferred temperature’. Thermal constant: The total heat energy required to complete a certain stage of development in the life cycle or in the completion of a physiological process of a species is constant and is termed as thermal constant and measured in Day - Degrees. Under unfavourable seasonal temperature the insects suspend their activities. These are of two types 1) Hibernation: A period of suspended activity in individuals occurring during seasonal low temperature 2) Aestivation: A period of suspended activity of individual occurring during seasonal high temperature or in a dry weather. Fecundity Insects fecundity will be maximum at moderately high temperatures and declines at upper and lower limits of favourable temperature. Aphids remain parthenogenetic under high temperature and many hours of sunshine while the opposite condition give rise to oviparous forms. Distribution: Tropical and subtropical conditions as in India are ideal for the distribution and establishment of insects. Mediterranean fruit fly Ceratitis caiptata Wiedemanncould not establish in England and North Europe since its immature stages cannot stand below 10°C. Mosquitoes are more abundant at 70 to 80°F but are rare at 112 to 113°F. Pink boll worm of cotton Pectinophora gossypiella (Saunders) is serious in Punjab where the temperature is within 95.5°F in August and September and not present in West Pakistan due to high temperatures at that period (99° F). Dispersal and Movement: Insects try to move away from unfavorable temperatures. The rice weevil Sitophilus oryzae(Linnaeus) is found in the upper layers of bins irrespective of whether the initial infestation started at the depth of the bin or at surface due to rise in temperatures i.e. when the temperature reaches 32°C, the adults migrate to cooler upper layer. Mass flight of desert locust Schistocerca gregaria (Forskal) or migration  13 starts at 17 to 22°C and they do not migrate when temperature is in between 14 to 16°C. Adaptations to temperature: At high temperature, locusts expose minimum body surfaces to sun’s rays by lying parallel to them while they expose maximum body surface to sun’s rays at low temperature lying at right angle to them. b) Moisture Insect body consists of 80 to 90 per cent water. Aquatic larvae contain about 98 per cent while insects which feed on dry food like Tribolium sp,Sitophilussp etc. constitute about 50 per cent. Water is generally lost through spiracles and integument. Insects cannot afford to lose more water than they take and hence conserve water depending on the situation. Adaptations to conserve moisture: 1. Body pigments: Insects develop dark pigment in cooler areas which help to absorb more heat from sun for raising body temperature. This aids in getting rid of excessive moisture from the body. Light colour in desert insects helps to reflect sun’s rays and save them from excessive evaporation. 2. Integument: Well developed integument and fused sclerites in beetles end weevils aid in conserving body moisture. Waxy coating of integument also saves from excessive evaporation. 3. Winglessness: Grasshoppers and crickets in arid regions have poorly developed wings and some are wingless by which the area of evaporation is reduced. 4. Pilocity: Dense hairs on the body prevent evaporation. 5. Form of body: Oval and compressed body of some desert beetles protects them from hot winds. Some desert insects have burrowing habit by which they go into deeper layers of soil when sufficient moisture is not available. 6. By reabsorption of water from products of excretion. 7. Some insects links Amsacta spp. enter into aestivation when dry conditions prevail. The fall of water content of body below a certain minimum proves disastrous to insects and if it is considerably above the normal (in very wet places) harmful effects like disease outbreaks are noticed in insects. Humidity: Unlike in temperature, there are no definite ranges of favourable humidity to all insects. Different species and their different immature stages have their own range. Humidity effects the speed of development, fecundity, colour etc. If water content of the body is high, dry air accelerates the development. Locusts sexually mature quicker and the number of eggs laid are more at 70% R.H. Rhinooceros beetle develops dark  14 chitin in moist air and light chitin in dry air. Survival is indirectly affected by extremely high humidity conditions thatfavours the spread of diseases in insects. c) Rainfall: Relative humidity is dependent on rainfall. The total amount of rainfall distribution in time influences the abundance of insects in an area. More than 12.5 cm rain during May-June results in increase in soil moisture which is not favorable to the cutworms and hence forced to come out of the soil and fall a ready prey to their parasites and predators. On the other hand if the rainfall is less than 10 to 12.5 cm during summer, cutworms remain protected in soil and there is outbreak of the pest in next season. Hence, the outbreak of pest can be forecasted, if the number of wet days (0.8 cm) during May-July isnoted. If there are less than 10 wet days there will be an increase of cutworms in the following year. If there are more than 10 wet days there will be a decrease. Desert locust does not lay eggs and even if laid does not hatch unless soil has sufficient moisture. Rainfall also plays an important role in movement of swarms of desert locust. Saturated condition of moisture is injurious for the development of spotted boll worm Earias fabia Stoll. Red pumpkin beetle Aulacophora foveicollis Lucas withholds eggs until it come across moist soil. Rain induces emergence of most of the insects from soil. Eg: Ants, termites, red hairy caterpillar, root grub beetles etc., emerge out from the soil after the receipt of rains.  15 LECTURE NO.3 Light Sunlight is the greatest single source of energy for all most all biological systems. Light as an ecological factor has been defined as all shorter wavelengths of radiant energy up to and including the visible spectrum which is measurable. Wavelengths of visible parts of spectrum range from 4000 (Violet) to 7600 (Red) Angstroms. Light is a non lethal factor. It helps in orientation or rhythematic behaviuour of insects, bioluminescence, period of occurrence and inactivity. The different properties of light that influence organisms are illumination, photoperiod, wave length of light rays, their direction and degree of polarization. Visible and ultra violet light influences the following: 1. Growth, moulting and fecundity: silkworms develop faster in light than in darkness. Grubs of Trogoderma also develop more rapidly in light. Moths of spotted boll worm of cotton and red hairy caterpillar lay most of their eggs during periods of darkness. The bean weevil lays more eggs in total darkness than in light. 2. Other activities: In honey bees there is a correlation between hours of sunshine and their activity. Orientation of animals through directed movements by light is called phototaxis which also depends on temperature, moisture, food and age. Green leafhopper, Nephotettix spp. are attracted to light on hot and humid evenings but is indifferent to it during dry weather. Chafer beetles, many moths pass the day in concealment. Cockroaches hide during day time. Dusk is most usual time for flight and copulation of moths, for emergence of winged whiteants etc. Based on daily activity cycle, insects or animals are categorized as Diurnal: Insects whichare active during daylight hours Nocturnal: Insects whichare active at night Crepuscular: Insects whichare active at dusk Photoperiodism: The number of hours of light in a day length (24 hours) is termed as photoperiod and the response of organisms to the photoperiod (length of the day) is known as photoperiodism, photoperiod induces diapause. Insects in which dispause is induced by long day are known as short day species. Eg: Mulberry silkworm Bombyx mori (Linnaeus).While the insects in which diapause in induced by short day lengths are known as long day species. Eg. Pink bollworm of cotton, Pectinophora gossypiella. Photoperiod also known to control mode of reproduction, body form etc. In reduced photoperiod sexual forms (winged) are produced in aphids.  16 3. Oviposition: Light stimulates oviposition in mantids and inhibits in Periplaneta sp. 4. Pigmentation:In dark areas, pigmentation develops in insects i.e., dark colour develops in dark areas. Bioluminescence: Famous luminous insects are the glow-worms and fireflies. The enzyme luciferase in the presence of oxygen and adenosine triphosphate (ATP) promotes the oxidation of luciferin. This causes the production of light in insects. In most cases, females produce flash of light to attract males for mating. Use of light as a factor in insect management: Many insects are either attracted or repelled to artificial light and this reaction is known as phototaxis. Grubs of Trogoderma sp. show negative reaction and are termed photonegative species. Most of the moths are attracted to light and are known as photopositive or phototropic. Based on this principle artificial light can be employed as a source for attracting insects and there after they can be trapped and destroyed and these devices are known as light traps. e) Other factors: i) Atmospheric pressure: it is generally of little importance.Locust show great excitement and abnormal activity about half an hour before the occurrence of storm when the atmospheric pressure is low. Drosophila flies stop moving when put under vacuum. ii) Wind and Air currents: Most of the insects will not take flight when speed of wind exceeds the normal flight speed. Air currents, especially in the upper air being strong, carries many insects like aphids white flies, scales etc. to far-off places and is an important factor in dispersal. Air movement may also be directly responsible for death of insects. Severe wind coupled with heavy rains cause mortality and moisture evaporation from body surface of insects. f) Edaphic (Soil) factors: Loamy soils allow digging and burrowing operation and are usually favourable for insects. Agrotis splive in soil of fairly light texture in which they move around freely in response to daily or seasonal temperature and moisture changes. BIOTIC FACTORS A) Food: Each insect species has certain nutritional requirements for completion of its life cycle. Under normal conditions there is a happy adjustment between the host and particular species of insect. But in the event of sudden increase in population, the  17 densities of population become too high to be supported by the food available in the area. Hence competition for food as well as space will be there. According to nutritional requirements, insects are categorized into: 1. Omnivorous: Which feed on both plants and animal. Eg. Wasps, cockroaches 2. Carnivorous: which feed on other animal as parasites and predators. Eg: Predators (Lady bird beetles and Mantids) 3. Herbivorous: which feed on living plants (crop pests) and these can again be categorized into (a) Polyphagous: which feed on wide range of cultivated and wild plants. Eg. Locusts, grasshoppers (b) Monophagous:which feed on single species of plants. Eg: Rice stem borer (c) Oligophagous:which feed on plants of one botanical family. Eg: Diamondback moth, Cabbage butterfly. 4. Saprophagous (Scavengers): which feed on decaying plants and dead organic matter. Eg: Drosophila flies, House flies, scarabaeid beetles. B) Other organisms: Includebeneficial and harmful insects. Associations of individuals of the same species is known as intra specific relations and it may be beneficial. Such association of two sexes, parental care, associations of social insects etc., phenomenon like overcrowding is harmful since shortage of food and space results. Disease outbreak may occur. Cannibalism may occur. Eg. Preying mantids, larvae of Helicoverpa, Tribolium feeds on its own eggs. Associations of individuals of different species are known as inter-specific relations and these may be beneficial or harmful. Beneficial associations: i) Symbiosis: Inter relationship between organisms of different species which live in close union without harmful effects are known as symbiosis, each member being known as symbiont. ii) Commensalism: One insect is benefited by living on or inside another insect without injuring the other and is known as comensal and it lives on the surplus food or the waste food of its host. Eg: Gall forming insects. When the commensal uses its host as a means of transport the phenomenon is termed as phoresy. Eg: Telonomus beneficiensparasitoid attaches themselves to the anal tufts of female moths of rice stem borer Scirpohaga incertulas (Walker) for their transport. The parasitoid parasitizes freshly laid eggs. iii) Mutualism: When both the symbionts are benefited by the association it is known mutualism Eg: Ants and aphids. Termites and flagellates. Harmful associations: Those that live with the expense of other living organisms are parasites and predators.  18 Parasite: Parasite is one which attaches itself in the body of the other organism either externally or internally for nourishment and shelter at least for a shorter period if not for the entire life cycle. The organism which is attacked by the parasite is called host. Parasitoid:An insect parasite of arthropod is parasitic only in immature stages, destroys its host in the process of development and free living as an adult or Parasitoid is an insect that feeds on the body of another insect or arthropod during the larval stage of the their life cycle and adult is a free-living insect, no longer dependent on the host. Parasitisation: It is the phenomenon of obtaining nourishment at the expense of the host to which the parasite is attached. Parasites can be grouped into, Depending upon the nature of host, as 1. Zoophagous : That attack animals (Cattle pests) 2. Phytophagous : That attack plants (Crop pests) 3. Entomophagous: That attack insects (Parasitoids and Predators) Predators and Predatism: A predator is one, which catches and devours smaller or more helpless creatures by killing them in getting a single meal. Insect killed by predator is known as prey. Insect Predator: It is defined as the one, which is - Large in size - Active in habits - Capacity for swift movements - Structural adaptations with well developed sense organs to catch the prey - May remain stationary and sedentary - Suddenly seize the pray when it comes with in its reach Eg. Antlions - Feed upon large number of small insects every day - May have cryptic colourations and deceptive markings Eg. Preying mantids and Robber flies  19 LECTURE N0. 4 CONCEPT OF BALANCE OF LIFE The population of an insect or any animal may be defined as the number of individuals of a particular species existing in a particular area at a time. The population never remains constant for long, but it tends to oscillate all the time about a theoretical optimum for the species. Balance of life in nature is the maintenance of a more or less fluctuating population density of an organism over a given period of time within certain definite upper and lower limits by the action of biotic and abiotic factors. Factors Contributing to Population Increase Any organism will multiply enormously if the environment is optimum. Different organisms multiply at different rates. Hence it is well known that every organism has an inherent capacity to survive, reproduce and multiply in numbers. The extent to which a species can multiply in a given period of time if no adverse factors interfere is called its ‘Biotic potential’ which is also known as ‘Maximum reproductive power’. This concept was first introduced by R.N. Chapman in 1928. The biotic potential or innate capacity to increase depends on 1) Initial population: The more the initial population of an organism the more will be its progeny, 2) Fecundity: It is the average number of eggs laid by a female in its life. The more the fecundity the more will be the resultant population. 3) Sex ratio: It is the ratio of females to the total population and is represented by number of females / Total number of males and females. Up to a limit the more the proportion of females, the more the multiplication capacity. 4) Number of generations in an unit time or a year: Obviously the greater the number of generations in a unit time the larger will be the resultant population. Based on the above factors the biotic potential can then be represented by the formula, B. P. = P (f s )n Where, P = Initial population f = Fecundity s = Sex ratio n = Number of generations in a unit time. Some insects like whiteant queens and house flies lay large number of eggs while others lay very few eggs. Some insects reproduce very fast. Mustard aphid has over 40 generations a year. If all survive, a single pair of house flies may produce 191, 010, 000, 000, 000, 000, 000, flies from April to August which if spread over the entire earth form a layer about 14 meters deep. Similarly a progeny of a pair Drosophila flies produced in a year would cover the whole of Indian subcontinent and Myanmar with a solid cake of flies. Such is the biotic potential of insects when there is no interference of biotic and abiotic factors of the environment.  20 Factors Tending to Reduce Populations: However, in naturethere are other powerful factors working against the biotic potential. These are (1) Abiotic or climatic factors and (2) Biotic factors. These biotic and abiotic factors are known as the constituents of environmental resistance which always tend to destroy a considerable proportion of insect life. The proportion of the population which is normally eliminated as a result of environmental resistance is known as ‘Normal Coefficient of destruction’ which can be expressed by the formula, Qn = 1 – ( 1/s )n / fn. Where, ‘Q ‘= the coefficient of destruction, ‘s= the sex ratio when population is taken as 1 n = the number of generations in a unit interval of time and ‘f ‘= fecundity. Balance of Life In nature there are two sets of tendencies namely the biotic potential tending to increase the population and the environmental resistance tending to reduce the population. As such there is a constant interaction between these two opposing forces and then maintains a dynamic equilibrium known as ‘Balance of life’. It is evident from the above that in any case, the insects or other animals never attain the high density which they are potentially capable of doing which is because of environmental limiting factors like abiotic factors comprising mainly temperature and humidity which at too high or too low levels adversely affects insects. Natural disturbance like heavy rain, hail storms, snow, sand storms, dust storms, and very high wind velocity are adverse to insect life. Biotic factors i.e. limitation of food, competition for food and space and natural enemies act adversely depending on the density of population. Causes for Outbreak of Pests in Agro-ecosystems The insect’s pest problems in agriculture are probably as old as agriculture itself. However, under subsistence agriculture the pest numbers were generally low as the productivity was poor. The insects under favorable conditions multiply enormously and different species multiply at different rates. When the numbers of an insect increase, it reaches the pest status. Rapidly increasing human population during last century has necessitated intensification of agriculture through expansion of irrigation facilities, growing of new crops, introduction of improved and exotic varieties, application of increased amounts of agrochemicals.. Definitely modern agriculture technology package hasresulted in increased higher yields and it has also contributed in severe outbreaks of insect pests in agricultural crops.  21 Following are a few of factors that have contributed in outbreak of crop pests 1. Excessive use of nitrogenous fertilizers: Excess use of inorganic nitrogenous fertilizers creates congenial conditions for rapid multiplication and subsequent outbreaks of pests. Application of nitrogenous fertilizers gives luxurious growth of the crop and makes it more vulnerable to insect attack as in case of rice and cotton which show higher incidence of yellow stem borer and sucking insects like aphids, whiteflies and leafhoppers, respectively, because there will be no competition for food. 2. Indiscriminate use of pesticides: Sometimes use of insecticides as a prophylactic or curative measure results in reducing one of the competitive species of pests while allowing the others to multiply.Repeated use of same insecticides may also lead to the secondary infestation in which it is not effective. Continuous spraying of carbaryl on cotton against bollworms and on brinjal against shoot and fruit borer results in the mite infestation which is often very severe. Indiscriminate use of pesticides also destroys the natural enemies of the pest and sometimes leads to the pest outbreak. Application of deltamethrin, phorate etc in rice fields against BPH destroy its natural enemies like mirid bugs and spiders which are bioagents of BPH and sometimes enhance the population of BPH. Similarly, indiscriminate use of insecticides on cotton resulted in the outbreak of whitefly in Guntur and Prakasam districts during 1985. 3. Use of high yielding varieties and introduction of new crops: Mostly improved strains of crop plants are susceptible to pests. Sometimes, the insects which are considered of minor importance, become major importance with the introduction of new varieties and strains. The improved combodia cotton strains are highly susceptible to the spotted bollworm Earias sp. and the stem weevil Pempherulus affinis. The hybrid sorghum CSH-1 was severely attacked by shoot fly, Atherigona varia soccata stem borer Chilo partellus and ear head gall midge Stenodiplosis sorghicola. The rice variety RP 4-14 was subjected to severe attack by BPH. Spread of the gall midge resistant varieties surekha and kakatiya in Telangana region made the gall midge incidence negligible while other pests like BPH, stem borer and whorl maggot became serious pests on paddy. The growing of cabbage crop in the plains of Madurai district (Tamil Nadu) as a new venture resulted in the wide spread incidence of the green semilooper, Trichoplusia ni 4. Destruction of forests and bringing forest area under cultivation: The destruction of forest over wide areas for cultivation affects several of the weather factors viz.,temperature, humidity, rainfall, wind velocity etc., in that locality and thus set conditions favourable for some insects to develop enormously. The insects feeding on the trees and plants in the forest area are  22 driven to neighboring areas where they may infest the cultivated crops and become new pests. 5. Monoculture (intensive and extensive cultivation of crops without proper crop rotation). When a single crop is raised over extensive area, limitation of food gets nullified and there is no competition for food and shelter and these results in the increase in pest populations. The effect is more pronounced if the cropping is done in more than one season for the year. The incidence of borers is high when sugarcane crop is raised over extensive areas continuously. Rice grown continuously creates favourable conditions for stem borer, BPH , green leafhoppers. Cotton monocropping over large areas, prolonging the crop growth beyond the regular duration and non removal of crop residues before the next crop accentuates population of American bollworm Helicoverpa armigera and pink bollworm Pectinophora gossypiella Even if there is crop rotation with closely related crops or when there are alternative food plants for the insect pests concerned, again the population of insect pests is likely to increase. Cotton followed by bhendi increases the incidence of pests like bollworms, aphids, mites, whiteflies etc. 6. Introduction of a new pest in a new area: when an insect gets introduced into a favourable new area without its natural enemies it becomes more abundant. The wooly aphid, Eriosoma lanigerum, became a serious pest of the apple in Niligiris as there was no natural enemy of the pest to check its multiplication. It was brought under control only when its specific parasitoid Aphelinus mali was introduced from Punjab. 7. Accidental introduction of foreign pests: Immature and adult stages of certain insects adhere closely to the plants such as scales and aleurodids and those which bore into the tissues of plant parts such as leaf miners, stem borers, gall insects etc., and are more liable to be introduced into other countries. Some of such insects introduced into India from foreign countries are the diamond back moth Plutella xylostella on cruciferous vegetables the Sanjose scale Quadraspidiotus pernicioususon fruit trees on hills, the green mealybug Coccus viridis on coffee and the potato tuber moth Phthorimoea operculella, cotton cushiony scale, Icerya purchasi , serpentine leaf miner Liriomyza trifolii, Spiralling whitefly, Alerodicus dispersus , Coconut mite Aceria guerreoronis etc, 8. Destruction of natural enemies: The natural enemies keep the insect pests under check. The destruction of these either by man or other agencies tends to increase the population of insect pests in an area. Sometimes the weather conditions may be favourable to the pest and unfavourable to its natural  23 enemies. The insecticides may often affect the parasitoids and predators more than the host insects. DDT kills parasitoids and predators and thus encourages aphids, scales mealybugs and spider mites to multiply into enormous proportions. 9. Large scale storage of food grains: Large scale storage of food grains also leads to pest problems since there is plenty of food for stored product insects to feed, breed and multiply.  24 LECTURE NO. 5 PEST SURVEILLANCE Pest surveillance is the systematic monitoring of biotic and abiotic factors of the crop ecosystem in order to predict the pest outbreak or it is the study of the ecology of the pest which provides the necessary information to determine the feasibility of a pest management programme. By the Pest surveillance programmes, the population dynamics and the key natural mortality factors operating under field conditions can be known which in turn helps in devising the appropriate management strategies. Advantages 1. One can know how a pest is multiplying in an area and when it is expected. 2. Minimize the cost of plant protection by reducing the amount of pesticides used and in turn reduce environmental pollution. 3. Pest control measures can be initiated in time due to advance forecasting. 4. Useful for pest forecasting. 5. To find out natural enemy population 6. To study the influence of weather parameters on pests 7. Mark endemic areas 8. Maintain the stability of the agro ecosystem. Components of pest surveillance 1. Identification of the pest. 2. Distribution and prevalence of the pest and its severity. 3. The different levels of incidence and the loss due to the incidence. 4. Pest population dynamics. 5. Assessment of weather. 6. Assessment of natural enemies etc. This study will give advance knowledge of probable pest infestation and will help to plan cropping patterns and to get best advantage of pest control measures. Forecasting for Pest Management The Pest surveillance programmes are highly useful in forecasting of the pests. It is the advance knowledge of probable infestation by the pests in a crop. Insect forecasting service may serve (1) To predict the forthcoming infestation levels of a pest which is very useful in taking control measures and (2) To findout the critical stages at which the application of insecticides would afford maximum protection. During 1941 a nation wide pest forecasting system was established in Japan. Locust warning station in India was established in 1939.  25 Forecasting is mainly of two types. 1) Short term forecasting: Covers one or two seasons mainly based on the populations of the pest within the crop by sampling methods. 2) Long term forecasting: It covers large areas and based mainly on the possible effects of weather on the insect abundance. Eg. Locust warning stations. Forecasting is made through 1. Population studies carried over several years. 2. Studies on the pest life history. 3. Field studies on the effect of climate on the pest and its environment. 4. Predictions form the empirical data on the pests of the previous season. Pest surveillance and monitoring in India :Pest surveillance and monitoring form an integral part of IPM technology. Directorate of Plant Protection , Quarantine and Storage (DPPQS), Faridabad, is organizing regular rapid roving pest surveys on major field crops in different agro ecosystems in collaboration with ICAR and SAU’s and a consolidated report then issued by Plant Protection Adviser (PPA) to the Government of India. INSECT PESTS The word ‘Pest’ derived from the Latin word ‘Pestis’ meaning Plague. An insect reaches the status of a pest when its number increases and inflicts significant damage. ‘Pest’ is defined as insect or other organism that causes any damage to crops, stored produce and animals. Damage boundary is the lowest level of injury where the damage can be measured. Insect pests are divided into a) negligible 2) minor and 3) major depending upon the severity of damage caused on the plant. Pests that cause less than 5% loss in yield, is said to be negligible. Insects which normally cause a loss ranging from 5 to 10% are said to be minor pests and those which cause a loss of 10% or more in general called as major pests. Different Categories of Insect Pests The different categories of insect pests are 1. Regular pest: Occur most frequently (regularly) in a crop and have close association with that particular crop. Eg: Chilli Thrips Scirtothrips dorsalis , brinjal shoot and fruit borer, Leucinodes orbonalis 2. Occasional pests: Here a close association with a particular crop is absent and they occur infrequently. Eg: Rice case worm, Nymphula depuctalis castor slug caterpillar, Parasa lepida , mango stem borer, Batocera rufamaculata  26 3. Seasonal pests: Occur mostly during a particular part of the year, and usually the incidence is governed by climatic conditions. Eg: Red hairy caterpillar on groundnut-June - July, Rice grasshoppers –June-July, Paddy climbing cutworms. 4. Persistent pests: Occur on a crop almost throughout the year.Eg: Scales and mealybugs on many crops, thrips on chillies, paddy stem borer. 5. Sporadic pests: Occur on a few isolated localities. Eg: coconut slug caterpillar – Macroplectra nararia, Contheyla rotunda, Rice earhead bug - Leptocorisa acuta,, castor slug caterpillar-Latoia lepida 6. Epidemic pest: Occur in a severe form in a region or locality at a particular season or time only. Eg: Rice hispa, Dicladispa armigera, rice leaf roller, Cnaphalocrocis medinalis 7. Endemic pest: Occur regularly and confined mostly to a particular area or locality. Eg: Red hairy caterpillar Amsacta albistrigaon groundnut in Kurnool, Ananthapur, Kadapa, Chittoor, Srikakulam and Vizag districts, stem borers of rice, paddy gall fly in Warangal districts.  27 LECTURE 6 INTEGRATED PEST MANAGEMENT (IPM) Modern concept of pest management is based on ecological principles and integration of different control tactics into a pest management system Integrated control was defined by Stern et al., (1959) as applied pest control which combines and integrates the biological and chemical control. Later the concept of pest management has gained importance.The idea of managing pest population was proposed by Geier and Clark 1961 who called their concept as protective management which later was shortened as pest management. Later Smith and Van Den Borsch in 1967 mentioned that the determination of the insect numbers is broadly under the influence of total agro ecosystem and the role of the principle element is essential for integrated pest management. In 1972 the term IPM was accepted by CEQ (Council of Environmental Quality) where IPM includes I - Integration that is harmonious use of multiple methods to control the impact of single pest as well as multiple pests. P - Pest- any organism that is detrimental to humans including vertebrates and invertebrate or weed or pathogens. M - Management refers to a set of decisions or rules based on ecological principles, economic and social consideration. The backbone of management of pest in an agricultural ecosystem is the concept of economic injury level (It is the level of the pest up to which the damage can be tolerable) According to FAO (1967), IPM was defined as “a pest management system in the context of associated environment and population dynamics in pest species. It utilizes all suitable techniques and methods in as compatible manner as possible and maintains the pest population at levels below those cause economic injury. OR Protective management of the noxious pest in which all available techniques should be evaluated and consolidated to manage pest population so that economic damage is avoided and adverse side effects on the environment are minimized (Gieir and Clark, 1961). Evolution of IPM Green revolution has attain self sufficiency in food through introduction of hybrids and high yielding varieties. Intensive cultivation of HYV invited or demanded more of inputs in the form of fertilizers especially inorganic which in turn attracted more of pest and diseases. This necessitated intensive control measures to curtail the damage caused to the crops and the control was achieved mainly through chemical pesticides. Continuous use of chemical pesticides led to pest resurgence, resistance, residues and ecological imbalance by killing predators and parasitoids thus affecting prey-predator  28 dynamics and resulting in environmental pollution. The importance of integrated approaches to pest control was then felt and the concept of IPM evolved. Why Pest Management 1) Collapse of control system: After World War II the use of pesticides mushroomed, but with all the benefits of the use pesticides, it has adverse side effects not just on humans but also in animals. During the massive use of pesticides, Rachel Carson, an American biologist, warned the people about the side effects of the use of pesticides through her book entitled, Silent Spring. Through her book, she raised a lot of questions about the real benefits of the use of pesticides as well as the risks of pesticides rendered in the environment and public health. An over-reliance on chemical pesticides led to development of pesticide resistance, development of multiple resistance , emergence of secondary pest as major pests, resurgence of pests, elimination of natural enemies of pests, hazards to non- target species, hazards to agricultural workmen and deleterious effects on the environment, 2) Phases of crop protection (Collapse of control systems) Smith. R.F (1969) has classified World wide patterns of crop protection in cotton agro ecosystem into the following phases which are also applicable to other crop ecosystems A) Subsistence phase The crop is usually grown under non irrigated conditions. Crop does not enter the world market and is consumed in the villages or bartered in the market place. Crop yields are low. Crop protection is through natural control, hand picking, host plant resistance, other cultural practices and rarely insecticides are used. B) Exploitation phase The agricultural production increased from subsistence level to higher so as to reach the market. Pest control solely depend on chemical pesticides. These are used intensively, often at fixed intervals. Chemical control measureswere exploited to the maximum extent wherein new synthetic insecticides, new methods of application, intensive use of pesticides resulted in higher yields. C) Crisis phase After few years in exploitation phase, more frequent applications of pesticides and higher doses are needed to obtain effective control. Insect populations often resurge rapidly after treatments and the pest population gradually becomes tolerant to the pesticide. Another pesticide is substituted and pest population becomes tolerant to it too. Occasional feeders become serious pests. Excessive use of insecticides over a number of years led to serious problems like i) Pest resurgence ii) Pest resistance to insecticides iii) Change of pest status iv) Increase of production costs, etc.  29 D) Disaster phase As a result of all deleterious effects, the cost of cultivation got increased and the crops were not grown profitably. There were frequent encounters of crop failures and produce not acceptable at market (rejection of the produce due to residues), and finally collapse of the existing pest control system. E) Integrated control phase In this phase it is aimed to give the control measures to the optimum and not to the maximum. Pest management concept is followed to avoid crisis and disaster phases by a) Combination of the resources b) analysis of eco- factors c) optimization of techniques d) recognizing or restoring the pest at manageable level 3) Environmental contamination Presence of residues in foods, feed and organisms caused widespread concern about contamination of Environment Concepts of IPM IPM seeks to minimize the disadvantages associated with use of pesticides and maximizing socio, economic and ecological advantages. 1. Understanding the agricultural ecosystem An agro ecosystem contains a lesser diversity of animal and plant species than natural ecosystem like forests. A typical an agro ecosystem contain only 1-4 major crop species and 6-10 major pest species. An agro ecosystem is intensively manipulated by man and subjected to sudden alterations such as ploughing , inter cultivation and treatment with pesticides. These practices are critical in pest management as pest populations are greatly influenced by these practices. Agro ecosystem can be more susceptible to pest damage and catastrophic outbreaks owing to lack of diversity in species of plants and insects and sudden alternations imposed by weather and man. However, agro ecosystem is a complex of food chains and food webs that interact together to produce astable unit. 2. Planning of agricultural ecosystem In IPM programme the agricultural system can be planned in terms of anticipating pest problem and also the ways to reduce them that is to integrate crop protection with crop production system. Growing of susceptible varieties should be avoided and related crops shouldn’t be grown. Bhendi followed by cotton increases incidence of the spotted borer. Groud nut followed by soybean increases incidence of the leaf miner.  30 3. Cost benefit ratio Based on the possibility of pest damage by predicting the pest problem and by defining economic threshold level, emphasis should be given to cost benefit ratio. The crop life table to provide solid information analysis of pest damage as well as cost benefit ratio in pest management. Benefit risk analysis comes when a chemical pesticide is applied in an agro ecosystem for considering its impact on society as well as environment relevant to its benefits. 4. Tolerance of pest damage The pest free crop is neither necessary in most cases for high yields nor appropriate for insect pest management. Castor crop can tolerate upto 25 per cent defoliation. Exceptions occur in case of plant disease transmission by vectors. The relationship between density of pest population and profitability of control measures is expressed through threshold values. The terms used to express the levels of pest population are a) Economic Injury Level (EIL): Lowest population at which the pest will cause economic damage or it is the pest level at which the damage can no longer be tolerated and therefore it is the level at or before which the control measures are initiated. The amount of injury which will justify the artificial control measures is termed as economic damage. EIL is usually expressed as the number of insects per unit area b) Economic Threshold Level (ETL): It is the index for making pest management decisions. ETL is defined as the population density at which control measures should be applied to prevent increasing pest population from reaching the economic injury level. Relationship between EIL and ETL can be expressed as when no action is taken at ETL the population reaches or exceeds EIL. E.g.:- ETL value for BPH in rice is 25 insects/hill; Grasshoppers or cutworms is 1 insect/hill; rice stem borer -5% dead hearts; Gall midge of rice-5% silver shoots. c) General equilibrium position(GEP) It is the average population density of insect over a long period of time unaffected by temporary interventions of pest control.However the economic injury level may be at any level well above or below the general equilibrium. The EIL may be at any level from well bellow to well above the GEP. Based on this insects can be grouped into FOUR categories a) Negligible pest: Pop density never increases high enough to cause economic injury. ---------------------------- EIL Population ---------------------------- ETL density GEP  31 Time b) Occasional pest: Occasionally their density reaches EIL when their population is affected by unusual weather conditions or the injudicious use of insecticides. At their peaks of population density, some sort of intervention usually an insecticide is required to reduce their numbers to tolerable level. ---------------------------- EIL Population ---------------------------- ETL density GEP Time c) Perennial pest: EIL’s are slightly above the GEP and intervention is necessary at nearly every upward population fluctuation. The general practice is to intervene with insecticides whenever necessary to produce a modified average population density well below the EIL. ---------------------------- EIL Population ---------------------------- ETL density GEP Time d) Severe pest: They have EIL below the GEP. Regualr and constant interventions with insecticides are required to produce marketable crops. __________________ GEP ---------------------------- EIL Population ---------------------------- ETL density _______ MEP (Modified Equilibrium Position) Time EIL decreases as the value of crop increases. It also depends on the stage of the crop, stage of the pest etc.  32 5. Leaving a pest residue Natural enemy population isgradually eliminated not only in the absence of their respective insect hosts because of the indiscriminate use of broad spectruminsecticides, which inturn also eliminate natural enemies. Therefore, it is an important concept of pest management, to leave a permanent pest residue below economic threshold level, so that natural enemies will survive. 6. Timing of treatments Treatment in terms of pesticide spray should be need based, with minimum number of sprays, timely scheduled, combined with improved techniques of pest monitoring and crop development E.g.: Use of pheromone traps for monitoring of pest population 7. Public understanding and acceptance In order to deal with various pest problems special effort should be made for effective communication to the people for better understanding and acceptance of pest management practices. The IPM practices followed should be economical and sustainable. Limitations of IPM:An IPM program requires a higher degree of management: Making the decision not to use pesticides on a routine or regular basis requires advanced planning and therefore a higher degree of management. This planning includes attention to field histories to anticipate what the pest problems might be, selecting crop varieties which are resistant or tolerant to pest damage, choosing tillage systems that will suppress anticipated pest damage while giving the crop the greatest yield potential. IPM can be more labour intensive, consistent, timely and accurate field scouting takes time. Without this information,intelligent management decision cannot make. Success of IPM programmes can be weather dependant. Therefore good IPM planners will have a alternate plan for when these problems arise. Different components or tools of IPM include, 1) Pest serviellance 2) Cultural methods 3) Mechanical methods 4) Physical methods 5) Biological methods 6) Legislative methods and 7) Chemical methods  33 LECTURE No 7 HOST PLANT RESISTANCE Relative amount of heritable qualities possessed by the plant which influence the ultimate degree of damage done by the insect is called ‘Host plant resistance’ to insect attack. Lesser damage than average damage is taken as resistance while more damage than average damage constitutes susceptibility. A resistant variety produces higher yield than susceptible variety when both are subjected to the same extent of infestation by same insect at the same time. Resistance is a relative term only compared with less resistance or susceptibility. Absolute resistance or Immunity refers to the inability of a specific pest to consume or injure a particular variety under any known-conditions. Immune varieties are rare. Ecological Resistance or Pseudo Resistance or Apparent Resistance Ecological resistance relies more on environmental conditions than on genetics. Certain crop varieties may overcome the most susceptible stage rapidly and thus avoid insect damage. Early maturing crop cultivars have been used in agriculture as an effective pest management strategy. However, plants that evade insect attack by this mechanism are likely to be damaged if the pest populations build-up early. Pseudoresistance may be one or combination of the following: 1. Host evasion: Under some conditions , a host plant may pass through the most susceptible stage quickly or at time when insects are less in number. Eg:Early planting of paddy in kharif minimize the infestation of stem borer Scirpophaga incertulas Sowing of sorghum soon after onset of monsoon in June helps to overcome shoot fly infestation 2. Induced resistance: is a form of temporarily increased resistance asresulting from some conditions of plant or its environment such as changes in the amount of nutrients or water applied to the crop. Eg: Application of potassium fertilizers. 3. Host escape: It refers to lack of infestation or injury to the host plant because of transitory circumstances like incomplete infestation, thus finding of uninfested plant in a susceptible population does not necessarily mean that it is resistant. Genetic Resistance The factors that determine the resistance of host plant to insect establishment include the presence of structural barriers, allelochemicals and nutritional imbalance. These resistance qualities are heritable and operate in a concerted manner, and tend to render the plant unsuitable for insect utilization.  34 Genetic resistance may be grouped based on, A. Number of genes i) Monogenic resistance:When resistance is controlled by a single gene, it is called monogenic resistance ii) Oligogenic resistance: When resistance is governed by a few genes, it is called oligogenic resistance. iii) Polygenic resistance: When resistance is governed by many genes, it is called polygenic resistance. This is also termed as horizontal resistance. B. Major or minor genes i) Major gene resistance: The resistance is controlled by one or few major genes. Major genes have a strong effect and these can be identified easily. This is also called Vertical resistance. ii) Minor gene resistance: The resistance is controlled by a number of minor genes, each contributing a small effect. It is called minor gene resistance. This is also referred to as horizontal resistance. C. Biotype reaction i) Vertical resistance: If a series of different cultivars of a crop show different reactions when infested with different insect biotypes, resistance is vertical. In other words, when infested with the same insect biotype, some cultivars show a resistant reaction while others show a susceptible reaction. It is also referred to also as a qualitative or biotype- specific resistance. Vertical resistance is generally, but not always, of a high level and is controlled by a major genes or oligogenes. It is considered less stable. ii) Horizontal resistance: Horizontal resistance describes the situation where a series of different cultivars’ of a crop show no differential interaction when infested with different biotypes of an insect. All resistant cultivars show similar levels of resistance to all biotypes. This type of resistance is called biotype-non-specific resistance, general resistance or quantitative resistance. Generally, horizontal resistance is controlled by several poly genes or minor genes, each with a small contribution to the resistance trait. Horizontal resistance is moderate, does not exert a high selection pressure on the insect, and is thus more durable or stable. Host Plant Selection Process by an Insect Host plant selection is a process by which an insect detects a resource providing plant within an environment of large population of diversified plant species. The process of host plant selection involves a sequence of five steps 1. Host-habitat finding: The adult population of any species arrives at general host habitat by phototaxis or anemotaxis and geotaxis. Temperature and humidity play important role.Normally crop pests stay within general area where crops are planted and hence, this becomes less important in host plant selection.  35 2. Host finding: After locating habitat the insect pest makes a purposeful search to locate its appropriate host plantfor its establishment. The essential visual or olfactory mechanisms help the contact. Once the pest reaches orcontacts the host plants, tactile and olfactory sensory organs arrest further movement causing the insects to remain on the plant. 3. Host recognition: Although larvae are with sensorial receptors for host recognition, this phase is usually taken care of by ovipositing female adult. It is usually done with the help of specific volatile from the plants. Eg:-Onion maggots,Delia sp attracted to its host by the odour of propryl disulphide. Cabbage maggot fly,Delia brassica get attracted by crucifer due to presence of few glucocyanolides. 4. Host acceptance: Various chemicals present in the host species actually govern the feeding process of insects. These chemicals responsible for initial biting,swallowing and continuation feeding. Eg: Presence of phagostimulants like morin in mulberry Morus albais key in continuation of feeding of silkworm Bombyx mori. 5. Host suitability: The nutritional value in terms of sugars, proteins, lipids and vitamins or absence of deleterious toxic compounds determines the suitability of the host for the pest in relation to the development of larvae, longevity and feeding. Mechanisms of Host Plant Resistance R. H. Painter (1951) has grouped the mechanisms of host plant resistance into three main categories. 1. Non-preference (Antixenosis) 2. Antibiosisand3. Tolerance Though various workers have attempted to classify the mechanisms of resistance, the terms defined by Painter (1951) - non preference, antibiosis and tolerance were widely accepted. However, Kogan and Ortman (1978) proposed that the term non preference should be replaced by antixenosis because the former describes a pest reaction and not a plant characteristic. The three types of resistance are described in the context of the functional relationships between the plant and the insect. Non-preference or Antixenosis: The term ‘Non-preference’referes to the responce of the insect to the charecteristics of the host plant, which make is unattractive to the insect for feeding, oviposition or shelter.Kogan and Ortman (1978) proposed the term ‘Antigenosis’, as the term ‘Non-preference’ pertains to the insect and not to the host plant. Some plants are not choosen by insects for food shelter or oviposition because of either the absence of desirable characters in that plant like texture, hairyness taste, flavour, or presence of undesirable characters. Such plants are less damaged by that pest and the phenomenon is called non preference  36 Eg. Hairy varieties of soybean and cotton are not preffered by leafhoppers for oviposition Open panicle of sorghum supports less Helicoverpa armigera Wax bloom on crucifers deter diamondback moth Plutella xylostella Antibiosis: Antibiosis refers to the adverse effect of host plant on the insect due to the presence of some toxic substances or absence of required nutritional components. Such plants are said to exhibit antibiosis and hence do not suffer as much damage as normal plants. The adverse effects may be reduced fecundity , decreased size , long life cycle , failure of larva to pupate or failure of adult emergence, and increased mortality. Indirectly, antibiosis may result in an increased exposure of the insect to its natural enemies. Eg: The most classical example ofhost plant resistance is DIMBOA (2,4 Di hydroxy -7- methoxy – 1,4 benzaxin – 3) content in maize which imparts chemical defense against the European corn borer Ostrinia nubilalis. Nutrionally related antibiotic effect in rice variety Mudgo which is resistant to BPH. When young females fed on variety Mudgo, ovaries of BPH are underdeveloped andcontain few mature eggs in it due to less quantity of aminoacid asparagine content in the resistant variety. Tolerance: Some plants withstand the damage caused by the insect by producing more number of tillers ,roots, leaves etc in the place of damaged plant parts such plants are said to be tolerant to that particular pest.Tolerance usually results from one or more of the following factors 1. General vigour of the plant, 2.Regrowth of the damaged tissues 3.Strength of stems and resistant to lodging 4. Production of additive branches 5. Efficient utilization of non vital plant parts by the insect and 6. Compensation by growth of neibhouring plants Eg: Early attack by the sorghum shoot fly on main shoot induced the the production of a few synchronous tillers that grow rapidly and survive to produce harvestable ear heads. LRG 41 Red gram for H. armigera Transgenic Plants ( Genetically modified or GM crops) A transgenic crop plant contains a gene or genes which have been artificially inserted instead of a plant acquiring them through pollination or simply a normal plant with one or more additional genes from diverse sources.Transgenic plants produce insecticidal or antifeedant proteins continuously under field conditions that proteins are enough to kill target pests.Bacillus thuringensis and cowpea trypsin protease inhibitors are ideal to impart resistance to insect attack.  37 B.t a naturally occurring gram positive soil bacterium, upon sporulation forms a parasporal crystal proteins called delta endotoxins. The cry proteins have selective toxicity to certain category of insects and require certain specific conditions for their effective action. The protein has to be ingested by the target insects which happens when they feed on the transgenic plant tissues. It requires an alkaline pH of 9.5 or above for effective processing into an active molecule which binds to specific receptors for binding before it can kill the target insect. All these conditions are available in the target insects and therefore they succumb when they feed on Bt-plants. Toxins binds to midgut and creates pores in the intestinal lining resulting in ion imbalance , paralysis of digestive system, after a few days that leads to insect death To develop a B.t transgenic plant, Selection of strain of B.t Identify the genome Isolation of genes (Cry genes,Cry1A, Cry1Ac &Cry3Ab) Introduction into plants through genetic engineering methods Transgenic technology can be utilized to develop plants with various beneficial traits such as a) Crop protection traitswhich include resistance to pests, diseases and herbicides b) Abiotic stressin the form of tolerance to drought, heat, cold or salinity, thus enabling plants to be grown in inhospitable habitats, adding more land for cultivation; and c) Quality traitsleading to enhanced nutrition; prolonged shelf-life or improved taste, colour or fragrance of fruits, vegetables and flowers; and increased crop yield India made its long-awaited entry into commercial agricultural biotechnology when the Genetic Engineering Approval Committee (GEAC), Ministry of Environment and Forests, Govt of India, at its 32nd meeting held in New Delhi on 26th March 2002 approved three Bt-cotton hybrids for commercial cultivation. This is a historic decision as Bt-cotton became the first transgenic crop to receive such an approval in India. These transgenic hybrids were developed by MAHYCO (Maharashtra Hybrid Seed Company Limited) in collaboration with Monsanto. IMPORTANCE AND HISTORY OF PLANT PROTECTION In modern India scientific study of insects was undertaken only from 18th Century. In 1898 the historical announcement was made on the discovery that Anopheles mosquitoes were the carriers of the malaria. Important institutions or organizations that contribute much for the plant protection in India are the Indian Agricultural Research Institute (IARI) which was the first established in Pusa in Bihar in 1905 and later shifted to New Delhi in 1937. Indian  38 Council of Agricultural Research (ICAR) was established in 1929. The Division of Entomology was established in 1905 as one of the five major Divisions of the then Agricultural Research Institute located at Pusa, Bihar and later it was shifted to New Delhi. Eminent entomologists like H.M. Lefroy, T. B. Fletcher, H.S. Pruthi, S. Pradhan and K.N. Mehrotra laid strong foundation for basic and applied research in insect science. After the realization of the harm, the pests are doing to human beings by carrying the diseases, the Plague Commission was established in 1905 and the Central Malaria Bureau was established in 1909 in New Delhi. The Government of India established a permanent Locust Warning Station in 1939 after experiencing the effect of locust cycle in 1926-32. The acute food shortage after the World War II and the Bengal famine in 1943 resulted due to the failure of rice crop by a paddy disease (Helminthosporiumoryzae.) which drew the attention of Govt. to prevent the damage of crops by pests and diseases to various crops. In 1946 the Government of India started the Directorate of Plant Protection, Quarantine and Storage.Plant protection schemes were introduced in different states from 1947 to look after the pest problems, to advise the Central and State Governments and to enforce quarantine laws for preventing the possible introduction of new pests from foreign countries along with imported materials. The Commonwealth Institute of Biological Control (CIBC) established its Indian station in 1957 at Bangalore. The Project Directorate of Biological Control (PDBC), Bangalore established in 1993, is nodal agency in India for organizing biological control research on agricultural pests at the national level. PDBC was upgraded as National Bureau of Agriculturally Important Insects (NBAII) in 2009 in order to exploit the agricultural insect resources from various agro climatic zones. In Andhra Pradesh, Central Plant Protection Training Institute was established at Hyderabad in 1966 mainly to train the personnel in plant protection. Later it was named as National Plant Protection Training Institute (NPPTI) and recently during 2008 renamed as National Institute of Plant Health Management ( NIPHM). National Centre for Integrated Pest Management (NCIPM), was established at Faridabad in 1988 to cater to the emerging plant protection needs of different agro- ecological zones of the country. Later it was shifted to New Delhi in 1995. Plant Protection Measures for Pest Control Early man caught the intruders by hand, killed them or cut away the infested parts of the plant and burnt them. These mechanical and cultural methods are followed till to date in pest management. Insecticides were in use from as early as 200 BC. A boiling mixture of bitumen and blowing the fumes through grape leaves was advocated to deter the insects, at about 100 BC. Sulphur was considered as pest averting material. Toxic nature of Arsenic was made to known in 40-90 AD. Chinese used Arsenic sulphides before 900  39 AD to control garden pests. Arsenic in honey was suggested as an ant bait since 1669. By 1690, tobacco was being used to control lace bugs on pear trees and other soft bodied insects. Pyrethrum was used before 1800 in Persia. Modern use of insecticides started with paris green in 1867 against Colorado potato beetle, Leptinotarsa decemlineata and lead arsenate in 1892 against the same. HCN (Hydrocyanic acid) fumes were used against scales in 1892. Discovery of the insecticidal properties of DDT in 1939 by Paul Muller revolutionized the insect control by chemicals and Muller was honered with Nobel prize in 1948 in medicinefor his dicovery. DDT was first synthesized by the German scientist, Orther Zieldler in 1874. Later so many other chemicals were evolved.The practical development of organophosphorous insecticide took place with the pioneering work of Schrader and his associates beginning in 1937. Indian pesticide market is the 12th largest in the World, which is 1.6 per cent of the global market. However per hectare consumption of pesticides in India is very low at 0.5 kg when compared to developed countries. In India 217 pesticide molecules (CIB, 2009) are registered for use, and 65 technical grade pesticides are manufactured indigenously. There are around 400 manufacturing units involved in production of technical grade pesticides and their formulations. Crop Losses Due to Insect Pests Insect pests cause huge losses ranging from 5 to 80% of even upto 100%. Acute food shortage following world war –II and Bengal famine (1943) due to failure of rice crop due to a paddy disease indicate the severity of the loss, caused by the pests and diseases. The insects in storage on an average consume and spoil an additional 4 million tones of grains every year.All this indicates the importance of plant protection by which we can save millions of tones of food grains which are otherwise eaten away by different pests. Losses due to insect pests in Indian agriculture are 23.3 per cent.One of the practical means of increasing crop production is to minimize the pest associated losses. Methods of Pest Control Any factor that is capable of making life hard for the insect that will repel or interfere with its feeding, mating, reproduction or dispersal can be taken as a method of insect control in its broadest application. They can be divided into two major categories 1. Natural control 2. Applied control Under natural control the population is kept under check by the environmental resistance without the interference of man. The control measures adopted by human agency are called applied or artificial control measures. Depending on the time of taking action the applied control measures may be  40 i. Preventive or prophylactic i.e. action taken to prevent the occurrence or spread of infestation and ii. Curative or remedial measures i.e. measures which are taken to kill the already existing pest population. Different meyhods of pest control / Components or tools of IPM are, I) Cultural methods II) Mechanical methods III) Physical methods IV) Biological methods V) Legislative methods and VI) Chemical methods  41 LECTURE NO. 8 I) Cultural Methods of Pest Control The manipulation of cultural practices at an appropriate time for reducing or avoiding pest damage to crops is known as cultural control. The cultural practices make the environment less favorable for the pests and or more favorable for its natural enemies. It is the cheapest of all methods. There are two categories of cultural methods, (a) Normal agricultural practices, which incidentally ward off certain pests: By adopting these, the farmers get two-fold benefits (1) Improvementof crop yields and (2) The population of certain pests do not increase abnormally i) Proper preparatory cultivation: Several insects which live or hide in the soil get exposed to sun as well as predators like birds etc due to Proper preparatory cultivation. Eg.Pupae of moths, roots grubs etc. ii) Clean cultivation: Removal of weeds which act as alternate hosts. Eg. Paddy gall fly Orseolia oryzae breeds on grasses such as Panicum sp., Cynodon dactylon etc. Fruit sucking moth larvae Eudocima ancilla on weeds of Menispermaceae iii) Systematic cutting and removal of infested parts: Keeps down subsequent infestation. Eg. Removal of sugarcane shoots affected by borers, Cutting and removal of infested parts of brinjal attacked by Leucinodes orbonalis Pruning of dried branches of citrus eliminates scales and stem borer. Clipping of tips of rice seedlings before transplanting eliminate the egg masses of stem borer. Clipping of leaf lets in coconut reduces the black headed caterpillar Ploughing and hoeing help to burry stages of insects or expose soil inhabiting insects to be picked up by birds. Pests like coccids get carried over to the next season through stubbles, which should be promptly removed. iv) Changes in the system of cultivation : Change of banana from perennial to annual crop reduced the infestation of banana rhizome weevil Cosmopolitus sordidus in addition to giving increased yields. Avoiding ratoon redgram crop during offseason helps in reducing the carry over of pod fly Melangromyza obtusa and eriophyid mite Aceria cajani v) Crop rotation: Crop rotation is most effective practice against pests that have a  42 narrow host range and dispersal capacity. Lady’s finger followed by cotton will suffer from increased infestation of pests. Hence if a non-host crop is grown after a host crop,it reduces the pest population. Eg. Cereals followed by pulses. Cotton should be rotated with non hosts like ragi, maize, rice to minimize the incidence of insect pests. Groundnut with non leguminous crops is recommended for minimizing the leaf miner incidence. vi) Mixed cropping: Intended for getting some return when one crop is attacked, the other escapes. Eg. Garden peas and sunhemp vii) Growing resistantvarieties: certain varieties resists pest attack. Eg: GEB-24 and MTU–5249 resistance to paddy BPH, Surekha variety to gall midge, TKM -6 and Ratna for stem borer. (b) Cultural practices specially adopted for certain pests 1. Adjusting planting or sowing or harvesting times to avoid certain pests : The manipulation of planting time helps to minimize pest damage by producing asynchrony between host plants and the pest or synchronizing insect pests with their natural enemies. Eg. Early planting o