CPP Plant Pathology PDF

PENGENALAN KEPADA PEROSAK TANAMAN (Introduction to Crop Pests) CPP1601 2  Dr. Muhamad Azmi Bin Mohammed BSc. (Hons) (UKM), MSc. (UKM), Ph.D (UKM) Bilik 106, Jabatan Sains Tanaman 086-855405 / 013-9148297 [email protected]  Ti...

PENGENALAN KEPADA PEROSAK TANAMAN (Introduction to Crop Pests) CPP1601 2  Dr. Muhamad Azmi Bin Mohammed BSc. (Hons) (UKM), MSc. (UKM), Ph.D (UKM) Bilik 106, Jabatan Sains Tanaman 086-855405 / 013-9148297 [email protected]  Time table üLecture: 10.00 – 12.00 PM (Tuesday) üAmali: 10.00 AM – 1.00 PM (Thursday) üVenue: Dewan Kuliah Utama (DKU) and Makmal Agronomi 1 üLab assistant: Pn. Salehah üTotal students: 53?  SINOPSIS Kursus ini meliputi pengenalan, interaksi, dan aspek biologi patogen dan organisma yang mampu membawa kemudaratan kepada tanaman berkepentingan ekonomi. Simptom kerosakan serta kaedah pengurusan perosak dan penyakit yang berkesan turut diberi penekanan. (This course covers the identification, interactions, and biological aspects of pathogens and organisms capable of causing harm to economically important crops. Damage symptoms and effective pest and disease management methods are also emphasized.) LEARNING OUTCOMES  TEACHING & LEARNING üLecture notes üAdditional notes üGroup presentation üQuiz üAssignments üSCL – Student-Centered Learning üLab reports *Refer to PutraBLAST PENILAIAN PERATUSAN (%) KERJA KURSUS 60 UJIAN 1 10 UJIAN TEKNIKAL 10 TUGASAN 10 LAPORAN AMALI 10 PEMBENTANGAN 10 KUIZ 10 PEPERIKSAAN AKHIR 40 CPP1601 Introduction to Plant Pests Introduction to Plant Pathology  What is a plant disease? A plant disease = any abnormal condition that alters the appearance or function of a plant. It is a physiological process that affects some or all plant functions. Disease may also reduce yield (quantity) and quality of harvested product. Disease = process or a change that occurs over time, does not occur instantly like injury.  What is a plant disease? Symptoms = visible effects of disease on plants - any detectable changes in color, shape, and/or functions of the plant in response to a pathogen or disease-causing agent. Signs = physical evidence of the pathogen, for example, fungal fruiting bodies, bacterial ooze, or nematode cysts - help with plant disease identification. Fungal fruiting bodies Bacterial ooze Nematodes cysts Symptom or sign??? Symptom or sign???  What causes plant disease? Infectious plant diseases = caused by living organisms that attack and obtain their nutrition from the plant they infect (parasitic). Pathogen = parasitic microorganism that causes a disease – eg. fungi, bacteria, viruses, and nematodes. Host = the plant/crop invaded by the pathogen and serving as its food source.  Types of pathogens Fungi Bacteria Viruses Nematodes The Disease Triangle t en Pa nm tho o vir gen En Host plant  Role of the environment Favorable environment = critically important for disease development – even the most susceptible plants exposed to huge amounts of a pathogen will not develop disease unless environmental conditions are favorable. Role of the environment The Disease Triangle Soybean rust?  The Disease Triangle Pathogen = Phakopsora fungi Soybean rust Environment Host plant = soybean = wet and humid  1. Fungi Vast majority = beneficial Can cause plant, human, and livestock diseases Most cannot be seen without a microscope Lack chlorophyll Composed of growing structure of delicate, threadlike filaments called hyphae Reproduce by forming spores  2. Bacteria Extremely small = requiring microscope to be seen Bacteria population can increase in number in short time period Cells clump together in masses = colonies Obtain food from dead or decaying organic matter or www.foodmate.net living tissue Spread plant to plant by wind-driven rain Gain entrance through natural plant openings or injuries  3. Viruses Most familiar = cause human and animal diseases such as influenza, polio, rabies, smallpox, and warts, and COVID-19 Cause some destructive plant diseases Size = very small, smaller than bacteria Are not complete living systems Survive only in living cells Transmitted to plant by insects = vectors  4. Nematodes Round, slender, threadlike worms Some are parasites on animals, insects, fungi, other nematodes, and plants Plant-parasitic nematodes have a stylet Most live in the soil and feed in or on plant roots  Inoculum Source of inoculum varies for each disease Inoculum = form of pathogen that can cause infection Fungi: spores Bacteria: bacterial cells Viruses: viral particles Nematodes: adult nematodes, juvenile stages, or eggs May be produced on residues left in the field Present in the soil Present in weeds or other crops in the area Present in or on the seed Present in soil sticking to equipment or tools Carried by wind or water Carried by insect vectors Carried in by animals, birds, and people  Disease cycle Survival 1. Inoculum produced = fungal spores, bacterial cells Production of survival 2. Dispersal = movement of inoculum structures Symptoms 4. Colonization = 3. Infection = pathogen pathogen establishing itself in penetrating into the host plant the host plant Adapted from P. Vincelli, 2005 Penetration of inoculum and infection Infection occurs when a pathogen successfully enters a plant and grows, reproduces, and spreads within the plant Pathogens enter a host through natural openings, wounds on plant surfaces, or by penetrating directly into the plant Spore Mycelial Pustule Penetration Sporulation germination growth formation  Comparison of disease cycles Fungi Bacteria Viruses Nematodes Survival Crop residue Crop residue - Crop residue Soil Soil - Soil Alt. hosts Alt. hosts Alt. hosts - - Insect vectors Insect vectors - Dispersal Wind Wind - Tillage Rain Rain - Equipment Insects Insects Insects Water run-off Infection Directly - - Directly Wounds Wounds - - Insect feeding Insect feeding Insect feeding -  FACTORS INFLUENCING PLANT DISEASE DEVELOPMENT 1. Inoculum level 2. Types of cultivars 3. Cultural practices 4. Environmental conditions 5. Harvesting  1. INOCULUM LEVEL/QUANTITY Successful infection may be dependent on the level of the inoculum (generally comprising fungal spores or bacterial cells) available Higher level of inoculum, higher potential of successful infection Amount of inoculum present is closely related to weather conditions during the growing season, particularly when the spores are dispersed by rain, eg. Phytophthora fungi = water mold  2. TYPES OF CULTIVARS Plant cultivars vary greatly in their susceptibility to diseases Some have high susceptibility to pathogens, some have high survival towards disease Eg. melons with a thick skin and firm texture are better than others (thin skin) to withstand in rigors of harvesting and handling – avoid being infected injured and infected by decaying bacteria  3. CULTURAL PRACTICES Can reduce the inoculum level through sanitation or to produce conditions less favourable for disease Practices such as pruning of fruit trees and destruction of crop debris markedly affect the survival of pathogenic microorganisms Application of pre-harvest fungicides can directly reduce the level of infestations However, pre-harvest chemical sprays with the same chemical that is designated for post- harvest application, can enhance the production of new fungal strains resistant to that fungicide.  4. ENVIRONMENTAL CONDITIONS May affect the pathogens directly - many pathogens persist in soil or survive on plant debris in the field, from which winds and rain may be directly responsible for their dispersal to potential hosts Phytophthora spp. which infect potato tubers or citrus fruits = dependent on rainwater for spores germination and initiation of infections Percentage of brown rot caused by Phytophthora parasitica in orange orchards was directly related to the amount of rainfall during infection period  5. HARVESTING Manual harvesting = injury level at minimum Mechanized harvesting = injury level at maximum, lead to wounds that may serve as suitable areas of penetration of pathogens Time of harvesting during the day = affect the keeping quality of the produce Most crops should be harvested in cool hours = early in the morning or at night  Potato Late Blight Late blight is caused by the oomycete: Phytophthora infestans. The disease spreads quickly in fields and can result in total crop failure. Late blight of potato was responsible for Sculpture in Dublin the Irish potato famine of the late 1840s. Potato late blight disease led to Irish Potato Famine  Rice Blast Blast is caused by the fungus: Magnaporthe oryzae. It can affect all above ground parts of a rice plant. Leaf blast infection can kill seedlings up to the tillering stage. At later growth stages, a severe leaf blast infection reduces leaf area for grain fill and grain yield. Paddy plant damaged by rice blast disease  Tobacco Mosaic Virus (TMV) Hosts for TMV include tomato and other solanaceous plants. Symptoms are very dependent on the age of the infected plant, environmental conditions, virus strain, and the genetic background of the host plant. TMV causes poor yield or distorted fruits, delayed fruit ripening and non-uniform fruit color.  Black Spot of Rose Black spot is caused by the fungus: Diplocarpon rosae. The disease does not kill the plant immediately, but the loss of leaves can weaken the plant making it more susceptible to other stresses. Black spot of rose is caused by fungus Diplocarpon rosae.  Panama Disease of Banana Fusarium wilt of bananas is caused by fungus: F. oxysporum f.sp. cubense, a common soil inhabitant. The causal pathogen attacks the banana's vascular system. At severe stage, the fungus grows out of the xylem into surrounding tissues. Fusarium oxysporum Internal browning of stem.  Summary Understanding the difference between a sign and a symptom is key in identifying a plant disease A plant disease cannot develop if a susceptible host, pathogen, and favorable environment do not occur simultaneously The major plant pathogens responsible for disease development in plants are fungi, bacteria, viruses, and nematodes The disease cycle describes the interaction of the pathogen with the host Group Presentations (Week 13 and 14): Insects in agriculture In your respective amali groups: Choose ONE (1) insect species based on their economic importance (pest or beneficial) describe on their: 1.Taxonomy 2.Morphology 3.Life cycle 4.Economic importance (Pest or Beneficial) 5.Damages? Host plants? Damaging life stages? How to control? and etc. (if pest) 6.Pollinators? Prey on what? attack mechanisms (predator or parasitoid?) (if beneficial) Each group will be given 15 minutes (all members MUST present).  Class activity (01/08/2024) In your respective amali groups: Prepare 2 diagrams of plant- disease triangle of 2 different plant diseases of your choice and provide additional related details Soybean rust: such as symptoms/signs, preventive methods, etc. Please submit next week 1. Pathogen = Phakopsora fungi during class. 2. Host plant = soybean 3. Environment = wet and humid  Pantun of the day: Kitaran penyakit berbagai fasa, Segala tanda harus dititikberat, Kalau hendak berbuat jasa, Tetapkan hati betulkan niat.