Pest Control Methods PDF

# Pest Control ## Methods of Pest Control: - Any factor that is capable of making life hard for the insect that repels or interferes with its feeding, mating, reproduction, or dispersal can be taken as a method of insect control in its broadest application. - Most of the control tactics that are c...

# Pest Control ## Methods of Pest Control: - Any factor that is capable of making life hard for the insect that repels or interferes with its feeding, mating, reproduction, or dispersal can be taken as a method of insect control in its broadest application. - Most of the control tactics that are commonly used today can be grouped into two broad categories: **natural controls** and **artificial controls**. ### Natural Controls: - By definition, a natural control may be any environmental factor that keeps a pest population below its economic injury level. - The population is kept under check by the environmental resistance without interference of man. - Examples include: - Geographic barriers - Cold temperatures - Natural enemies that keep population growth in check. ### Artificial Controls: - On the other hand, artificial controls employ products or processes of human origin to modify a pest's distribution, behavior, or physiology. - These methods are employed by human beings. - In fact, some of our most effective tactics are natural controls that we can improve, enhance, accelerate, or augment by appropriate human intervention. - Depending on the time of taking action, the applied methods be **preventive or prophylactic**, and **curative or remedial measures**. ## Methods of Pest Control - **Natural Control** - **Artificial Control** ## Artificial Control - **Cultural Methods** - **Preventive/Prophylactic** - **Curative/Remedial** - **Mechanical Methods** - **Physical Methods** - **Biological Methods** - **Chemical Methods** - **Legal Methods** - **Biotechnology Methods** ## Cultural Methods - **Cultural Methods:** Simple modifications of a pest's environment or habitat often prove to be effective methods of pest control. Such tactics are known as cultural control practices because they frequently involve variations of standard horticultural, silvicultural, or animal husbandry practices. - Since these control tactics usually modify the relationships between a pest population and its natural environment, they are also known, less commonly, as **ecological control methods**. - **Advantages of Cultural Control Tactics:** Simplicity, eco-friendly, easy to implement, and low cost are primary advantages and disadvantages are few as long as these are compatible with a farmer's other management objectives (high yields, mechanization, etc.). - Unfortunately, there are still a wide variety of insect pests that cannot be suppressed by cultural methods alone. - **Control of Insects Through Adoption of Ordinary Farm Practices:** Such practices can either eliminate or reduce insect populations. - To categorize cultural control methods, there are **two categories**: - **Normal:** Control one or few or many insects naturally. - **Special:** Implemented specially for certain insects. ### Normal Methods - **Proper Preparatory Cultivation:** Several insects which live or hide under soil in different forms/stages (larvae, pupae, grubs, etc.) get exposed to sun and predators such as birds. Summer deep ploughing exposes all resting stages of insects, such as larva and pupa to abiotic and biotic factors. For example, summer deep ploughing in Groundnut exposes pupa of Red Hairy Caterpillar Amsacta spp. - **Growing Suitable Varieties:** Selection of suitable resistant/tolerant varieties or hybrids helps managing the pest population and also gives good yields in endemic areas. - **Crop Rotation:** - Crop Rotation is one of the oldest and most effective cultural control strategies. - Growing a single crop year after year in the same field gives pest populations sufficient time to become established and build up to damaging levels. - The Crop rotation is stated as growing one crop after another on the same piece of land in different timings (seasons) without impairing the soil fertility. - It is a planned order of planting specific crops on the same field. - Crop rotation also means that succeeding crops are of a different genus, species, subspecies, or variety than the previous crop. - Examples would be legume after wheat, row crops after small grains, cereals after legumes, etc. - Rotating the field to a different type of crop can break the life cycle by starving pests that cannot adapt to a different host plant. - Rotation schemes also prove successful for controlling pests in pasture lands. - Insects can be controlled entirely or partially by rotations. The insect populations go up within a cropping system where only one or two crops continue to be grown over the time. - The insects are able to develop a parasitic relationship with the crop plants and perpetuate until the system is changed by alternation with crops. - Insects such as maize borer and stem weevil readily migrate to nearby or distant fields in the absence of maize. - In such cases, only partial control can be obtained by rotation. - Increasing field isolation from fields seeded with the same crop helps control insects. - Crop rotation schemes work because they increase the diversity of a pest's environment and create discontinuity in its food supply. - As a rule, rotations are most likely to be practical and effective when they are used against pests: - Attack annual or biennial crops - Have a relatively narrow host range - Cannot move easily from one field to another - Are present before the crop is planted. - Plants within the same taxonomic family tend to have similar pests and pathogens. - The crop rotation will help to avoid the buildup of pathogens and pests that often occur when one species is continuously cropped. - For instance, if annual vegetable crops are grown in the same place year after year, there is a risk that soil borne pests and diseases will become a problem. - Growing bhendi crop after cotton will increase the pest infestation (spotted boll worm Earias vitella, Earias insulana) (leaf hoppers Amrasca biguttula biguttula), whiteflies (Bemisia tabaci), and hence if the non-host crop is grown after the host-crop, insect population reduces. - Growing cereals followed by pulses will reduce pest populations since the insect pest sps of cereals are different from pulses. - For example, root-knot nematode is a serious problem for some plants in warm climates and sandy soils, where it slowly builds up to high levels in the soil, and can severely damage plant productivity by cutting off circulation from the plant roots. - Growing a crop that is not a host for root-knot nematode for one season greatly reduces the level of the nematode in the soil, thus making it possible to grow a susceptible crop the following season without needing soil fumigation. - Diamond backed moth (Plutella xylostella) can be controlled by rotating cabbage with non-cruciferous crops. - **Changing System of Cultivaion:** Change in banana from perennial crop to annual crop through regular planting of seed materials (not by ratoon system) helps in reduction of stem weevil (Odoiporus longicollois) in addition to increase of yields. - **Mixed Cropping:** Intercropping (also known as mixed cropping) is another way to reduce pest populations by increasing environmental diversity. - In some cases, intercropping lowers the overall attractiveness of the environment, as when host and non-host plants are mixed together in a single planting. - In other cases, intercropping may concentrate the pest in a smaller, more manageable area so it can be controlled by some other tactic. - Inter-cropping Cowpea with Sorghum can attract polyphagous insect pests on to sorghum which is less value crop. - The cotton system is ideally suitable for intercropping because of the relatively longer duration and its slow growth in the initial stages. - The common practice of cotton cultivation is inter or mixed cropping with pulses which reduces the sucking pest complex on cotton. - Similarly, planting of few rows of sorghum or maize in cotton reduces insect pest population due to disturbance of host selection process of insects. - Intercropping of Pigeonpea in Sunflower crop @ 1:2 reduces Bihar Hairy Ceterpillar Spilosoma oblique attack. - Strips of alfalfa, for example, are sometimes interplanted with cotton as a trap crop for lygus bugs (Miridae). The alfalfa, which attracts lygus bugs more strongly than cotton, is usually treated with an insecticide to kill the bugs before they move into adjacent fields of cotton. - **Clean Cultivation:** Sanitation is an important cultural strategy for protection of crops from arthropod (insect and mite) pests. Clean cultivation is often recommended as a way to eliminate shelter and/or overwintering sites for pest populations. - Sanitation for crops requires the destruction or removal of not only infested materials, and also potential sources of infestation. - Effective sanitation practices reduce and delay the onset of insect pest problems, and eventually can eliminate or minimize pest problems. - It is easier and less expensive to exclude pests than to control them after they appear. - **Removal of weeds/unwanted plants:** Weeds can act as alternate hosts which help reduce pest build-up. For example, paddy gall midge breeds on grasses like Cynodon, Panicium, and hence removal affects of gall midge survival. Trimming field bunds in paddy reduces grasshopper populations since they lay eggs on weeds. Weeds also offer shelter for many moths. Fruit sucking moth spends their larval stage on climber weeds(Cocculus pendulus, C. hirsutus, Tinospora cardifolia) belongs to Family Menispermaceae, usually found around orchards, and the adult damage the fruit crops. - **Systematic removal and cutting of infested plants/plant parts:** This helps keep down the subsequent infestation. Examples include: removal of sugarcane shoots affected by borers, twigs of brinjal affected by shoot and fruit borer (Leucinodes arbonalis), pruning of dried branches of citrus eliminates scales and stem borer, clipping tips of rice nurseries eliminates paddy stem borer (Scirpophaga incertulas) egg masses, ploughing and hoeing helps to expose the insect life cycles. - **Removal of plant residues/debris:** Such debris can harbor the insect stages which helps in reducing the pest density. Removing crop debris from cotton fields after harvest eliminates overwintering populations of pink bollworms (Pectinophora gossypiella), european corn borers (Ostrinia nubilalis), and sugarcane borers (Diatraea saccharalis). Collecting dropped fruit from beneath an apple tree reduces the next season' population of apple maggots (Rhagoletis pomonella), codling moths (Cydia pomonella). Removal of stubbles in paddy and sugarcane after harvest of the crop destroys resting stages of stem borers. - **Periodical Drying of Seeds/Stored Produce:** Helps in reduction of stored grain pests and also helps in cross infestation. ### Special Methods - **Adjusting Sowing/Planting Time:** In some crops, it is possible to create discontinuity in the pest's food supply simply by altering the time of year for planting or harvesting. This strategy, often known as phenological asynchrony, allows farmers to manage their crop so it remains "out of phase" with pest populations. Sweet corn, for example, can escape most injury from corn earworms (Helicoverpa zea) if it is planted in early spring and harvested before larvae mature. - Early planted rice crop escapes gall midge damage. This mechanism called as Psuedo-resistance as described by Painter, since the plants evade or escape the pest attack due to changes in environment and other factors, may be susceptible to the pest if occurs at right time and right stage of the crop. - Early planting in kharif and late planting in rabi minimizes the pest infestation on paddy stem borer (Scirpophaga incertulas). - Early sowing of redgram escapes the pod-fly (Melanagromyza obtuse) damage. - Delaying sunhemp sowing till the onset of south-west monsoon avoids sunhemp hairy caterpillar attack. - Careful timing of harvest dates in alfalfa can cause high mortality in populations of alfalfa weevil (Hypera postica) and alfalfa caterpillar (Colias eurytheme) by removing edible foliage before the larvae have completed development. - Harvest timing is often the most practical method available to foresters for controlling bark beetle (Scolytidae) infestations in pine plantations. Since trees become more susceptible to beetle outbreaks as they grow older, good management dictates that timber stands be harvested for lumber before the trees reach maturity. - **Trap Crops:** Pests are strongly attracted to certain plants. When these plants are sown in the main field or along the borders, the pests gather on them. Raising trap crops as inter and/or border crops is an important cropping system approach. - The trap crop distinctly attractive to the pest when compared to the main crop. It provides protection either by preventing the pest from reaching the main crop or by restricting them to a certain part of the field where they can be economically destroyed. Generally, these trap crops are planted on the borders of main crop. - Mustard along with cabbage is a trap crop for the control of the Diamond Backed Moth, aphids and the Leaf Webber. - African marigold @ 100 plants/acre, in cotton/chilli/tomato is a good trap crop for the Helicoverpa armigera, besides it also attracts the adults of the leaf minor which lay eggs on its leaves. Similarly, planting Hibiscus @ 100 plants/acre in cotton also attracts insect pests. - Castor is a good trap crop for tobacco cater pillar (Spodoptera litura) in chilli/cotton/tomato etc. - Maize plants can be a trap crop to attract fruit fly adults in vegetable cultivation where the fruit fly (Bactrocera cucurbiate) is a major problem. - Tomato is a good trap crop in citrus for fruit sucking moths (Othereis materna) - **Managed Application of Water:** This method can have a big impact on the survival of pest populations in some crops. - Regular rainfall (or overhead irrigation) can significantly reduce infestations of two spotted spider mites (Tetranychus urticae) in tree fruits. - For paddy cutworms, paddy swarming caters pillars, ragi cutworms, flooding the fields float these caterpillars leaving the plants. - Good irrigation keeps plants healthy, vigorous, and more resistant to insect injury. - Draining the paddy fields can reduce BPH populations, and also paddy caseworm which travel one plant to other through water. It is not unusual for small amounts of injury to actually stimulate compensatory growth in healthy plants. - **Managed Application of Fertilizers:** This method can have good positive impact on crop growth as well as negative impact on some specific pest populations. Higher does of nitrogenous fertilizers increases pest attack while pottasic fertilizer make plant more resistant. - Over dose of nitrogen application leads to stem borer attack in paddy, sucking pests in cotton, chilli etc - Root weevil attack in rice can minimized through application on 20kg ammonium phosphate and 40kg super phosphate/ha. - **Trash Mulching/Earthing Up:** Trash mulching/earthing up at month after planting of sugarcane reduces early stem borer (Chilo infuscatellus) attack in sugar cane. - **Alley Ways in Paddy:** Leaving gaps of 0.5m for every 5m width in paddy fields increases the aeration and light, and BPH (Brown Plant Hopper-Nilaparvatha lugens) incidence come down under highly aerated conditions. #### Advantages of Cultural Methods: - As we are using same cultural practices no extra cost is required. - This method is safe for application. #### Disadvantages of Cultural Methods: - This method is effective for single pest only. - There are no visible results observed. - This method is not effective at epidemic condition. - Detailed knowledge of biology of pest is required for this purpose. ## Mechanical Control: - The control of insects by mechanical methods is based on the principles of removal and direct destruction. - Mechanical control methods involve using barriers, or physical removal to prevent or reduce the pest problems. ### Preventive Barriers: - An example of a more common physical barrier is the window screening we use to keep pests out of our homes. Eg: mosquito nets and fly proof cages. - Trenching around crops prevents movement of army worms, like red hairy caterpillar (Amsacta albistriga) in groundnut, swarming caterpillar (Spodoptera mauritia) in paddy, and grasshoppers. Ditches or moats with steep vertical walls are occasionally used as barriers to keep crawling insects (e.g., chinch bugs or whitefringed beetles) from migrating out of one field and into another. Pitfall traps are dug at 3-5 meter intervals in the ditch and filled with kerosene or creosote to kill the pests. - Bagging in pomegranate fruits avoids infestation of pomegranate butterfly (Virachola Isocrates). Fruit sucking moth on citrus (Otheiris spp.) or pomegranate suck the juice with the help of stout which can be prevented by bagging fruits. - Water as barrier: Domestic pest like ant can be prevented with water. ### Hand Picking: - Egg masses and larvae or nymphs and sluggish adults can be handpicked from plants/plant parts. - Egg masses of paddy stem borer (Scirpophaga incertulas) can be handpicked and by leaf tip clipping during transplantation. - Egg masses of tobacco caterpillar (Spodoptera litura) can be handpicked. - Egg masses of red hairy cater pillar (Amsacta albistraiga) can be handpicked. - Early larval instars of Spodoptera can be handpicked from castor leaves. - Most of the adults can be picked up using sweeping nets. - Hand picking of egg masses and adults of Colorado potato beetle (Leptinotarsa decemlineata) was followed 100 years ago. ### Jarring and Shaking: - Shaking redgram plants for Helicoverpa larvae. - Shaking bushes and other plants for collecting damaged parts, eggs and larvae. - In 1920s some farmers dragged gunny bags over cotton plants to collect and destroy infested squares in cotton. - Running a rope over paddy crop for removal of case worms. - Adults of whitegrub gathers on neem or babhul tree so by shaking tree they can be collected and destroyed. - **Extraction:** Of rhinoceros beetle (Oryctes rhinoceros) from the coconut crown using an arrow headed rod. - **Tin Collars:** Over coconut plants prevent rat damage. - **Sticky Bands:** Around tree trunks can be used against red tree ant. Mealy bugs on mango come on soil for egg laying which can be prevented by putting sticky bands on stem. - **Beating with Stick:** When swarm of locust comes, it can be beaten with stick. - **Sieving and Winnowing:** Seed materials/food grains for stored grain pests. Pests of stored grains can be removed with this method. - One effective method for controlling gypsy moth larvae on small numbers of trees is to put a band of folded burlap around the tree trunk to provide an artificial resting site for the caterpillars, and then destroy the caterpillars that gather there. Fruit and shade trees can be protected from various pests (e.g., plum curculio, gypsy moth, and codling moth) by tying a band of folded burlap around the trunk with its open side facing down. As insects climb up the trunk, they are waylaid in the folds of burlap which can be treated with insecticide or inspected daily to collect the pests. #### Advantage of Mechanical Methods: - Skilled labours are not required. - Cost required is very less. - There are no any side effects. #### Limitations of Mechanical Methods: - Time and labour requirement is high. - This method is applicable only on small scale. - This requires repeated application.