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Plant Chemical Protection

Plant Chemical Protection. Department of Plant Protection School of Agriculture,Yangtze University. Preface.

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Plant Chemical Protection

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  1. Plant Chemical Protection Department of Plant Protection School of Agriculture,Yangtze University

  2. Preface Plant provide either directly or indirectly the main source of nutrition for mankind, animals and uncountable masses of lower organisms. An ample supply of food, fibers and other vegetable matter is a prerequisite to health as well as to social and economic development of any human society. Thus, the increase competition from all kinds of organisms, which cause injury, disease , is unwanted. Man is waging a continuous struggle against these injurious and troublesome organisms, called pest, pathogen and weed etal. in order to protect his food, shelter and living.

  3. Owing to the spectacular development of agriculture in general during the 20th century, word food production has grown considerable to the extent that per capital food production has increased in spit of the explosive growth of the world population. However, growth figures differ greatly for continents and individual countries. Developing country provide only about 30% of the world requirement of food although they are home to more than half of the global population, and agriculture accounts for more than 70% of their national income; in 1985, the ratios for malnourished and healthy people were 1:3 in Africa, 1:5 in east Asia and 1:7 in Latin American.

  4. In this book, the role of pesticide in agricultural productivity has been strongly emphasized to sustain the crop yield and quality over the world. However, the crop protection is very complicated because of the numerous interactions between the cultivated crops, the many damaging or beneficial organisms and the variable factors of the environment. The use of chemicals, having an enormously disruptive power on the fragile balance of nature, requires general insight into their properties and effects.

  5. Chapter 1 Basic Concept of Plant Chemical Protection 1 Definition and Class of Pesticide 2 Toxic Power of Pesticide 3 Effects of Pesticide on Crop 4 Toxicity of Pesticide 5 Principles for Safety Application of Pesticide

  6. Section 1 Definition and Classification of Pesticide Ddefinition of pesticides Classification of Pesticide • Classified According to source of Material and Component • Classified According to Use • Classified According to Functional Manner • Insecticides • Fungicides • Herbicides

  7. ▲ Classification ◆ According to Source of Material and Component: Inorganic Pesticide:Sulphur,Aluminium phosphide, Bordeaux mixture. Organic Pesticide : • Botanical Pesticide ; • Oil Insecticide; • Microbial Pesticide; • Synthetic-organic Pesticide .

  8. ◆ Classified According to Use: • Insecticide; • Fungicide; • Herbicide; • Acaricide; • Raticide; • Nematocide; • Plant Growth Regulator (Hormone mimics).

  9. ● Classification of Insecticides 1. Stomach poisons; 2. Direct contact poison ; 3. Fumigant; 4. Inner absorbent; 5. Antifeedant; 6. Repellentant; 7. Attractant.

  10. ● Classification of Fungicides 1. Protective fungicides; 2. Therapeutic fungicides; 3. Eradicant fungicides.

  11. ● Classification of Herbicides 1. Conducting herbicides; 2. Contacting herbicides; 3. Selecting herbicides; 4. Extinguishing herbicides.

  12. Section 2 Toxic Power of Pesticide Concept of toxic power of pesticide Measurement of toxic power Calculation of pesticide effects Insecticide Fungicide Herbicide

  13. Concept of Toxicity and Control Effects of Pesticide Toxic power:A measurement used as evaluated and compared index, which was generally determined under strict condition with insect, bacteria or weed by precision method. Control effects:Resulted from pesticides and multi factors ,which was determined under field condition. Toxicity:Generally refer to mammal and human being.

  14. Measurement of toxic power of pesticides 1.Unit shows toxic power: (1)Lethal Dose :LD50 (2)Lethal Concentration: LC50 (3)Effective Dose:ED50 (4)Effective Concentration EC50 (5)Knock-down Time: KT50 (6)Inhibition Concentration, IC50 2.Relative Toxicity Index

  15. Calculation of Effects of Insecticides • Calculation of adjusted mortality: • Where:X express percent survival in the untreated controls;Y express percent survival in the treated insect. • The approximation is permissible when the control mortality is less than 20% or is based on a large number or observation.

  16. Calculation of Control Effects of Insecticides Where Ta express the survival individual before treated in the treated controls; Tb express the survival individual after treated in the treated controls; Ca express the survival individual after treated in the untreated controls; Cb express the survival individual before treated in the untreated controls.

  17. Calculation of Control Effects of Herbicides Where Qa express the weed quantity in the treated controls; Qbexpress the weed quantity in the untreated controls.

  18. Section 3 Effects of Pesticide on Crop ▲ Damage of pesticide on the crops 1 Property of pesticides 2 Crop species,growth stage and physiological status 3 Environmental conditions 4 Symptom of damaged crop A. Acute symptom B. Chronic symptom ▲ Stimulate effects of pesticide on the growth of plant

  19. Effects of Properties of Pesticides on Damage on the Crops Pesticide properties: The difference of properties of pesticides play important affect on the damage effects of pesticide on crop. In general, inorganic pesticides have more hazard than organic pesticides to bring pesticide damage. Where K means safety index; Ca express the minimum concentration needed to prevent pest damage; Cb express the maximum concentration that plant can endure.

  20. Crop species, growth stage and physiological status The differences of tissue morphology and physiology of crop,such as the thickness of wax surface, quantity of covering hair , density and situation of closure of stomate,etc.,make varied crops have different sensibility to the pesticide damages.

  21. Environmental conditions The occurrence of pesticide damages not only has something to do with pesticide class and crop,but also has close connection with environmental conditions when pesticides were applied,mainly connected with the factor of temperature, humidity, dew,etc..

  22. Acute Pesticide Damage Acute symptom of pesticide damage emerged in a short period,even in hours after application of pesticides.

  23. Chronic Pesticide Damage Symptom of Chronic pesticide damages emerged slowly,it need a long time period or multiple application of pesticides.

  24. Stimulating Effects of Pesticide on Growth of Crops Tobacco formulation can improve the growth of paddy;derris formulation can promote the development of vegetable roots; In general, pesticides when sprayed in low dose would stimulate the growth of plant.But this positive effects should be affirmed with rigorous comparatively research.

  25. Section 4 Toxicity of Pesticides Definition of toxicity of pesticides Classification of toxicity of pesticides Acute toxicity Subacute toxicity Chronic toxicity

  26. Definition of Pesticide Toxicity Toxicity:The injurious effects of pesticide to man and all useful forms of life,which were measured by test on rat.Higher animals can take in pesticides via respiration,oral intake or through dermal contact to induce the occurrence of toxicity.

  27. Acute Toxicity If man or animal wrongly intake some pesticides with high grade toxicity,varied toxic symptoms would emerge in a short period,such as head faint, nausea, vomit, convulsion or decompensation,etc..That would take life risk if not cured in time.

  28. Subacute Toxicity Subacute toxicity need long time and continuate contact with pesticides,the toxic symptom emerged over a definite time,but finally would have alike symptom of acute toxicosis,sometimes would cause local pathology symptom.

  29. Chronic Toxicity In despite of low toxicity,some pesticides with steady property will maintain for a long time to pollute environment and food.They will accumulate in the body of men and animals after long period contact, damaging the function of the body and blocking normal physiologic metabolism.

  30. Section 5 Primary Principle of Scientific Pesticide Application Selecting pesticide according to pest characteristic; Make full use of pesticide properties; Take advantage of selectivity of pesticide; Environmental factors that influence control effects; Safe application of pesticide.

  31. Effects of Properties of Pesticides on Damage on the Crops Pesticide properties: The difference of properties of pesticides play important affect on the damage effects of pesticide on crop. In general, inorganic pesticides have more hazard than organic pesticides to bring pesticide damage. Where K means safety index; Ca express the minimum concentration needed to prevent pest damage; Cb express the maximum concentration that plant can endure.

  32. Chapter 2 Pesticide Formulation and Application Method 1 Relationship Between Pesticide 2 Dispersing and Its Application Efficiency Adjuvants 3 Main Pesticide Formulation 4 Application Methods of Pesticide

  33. Section 1 Relationship Between Pesticide Dispersing and Its Application Efficiency Difference between technical product ,formulation and preparation of pesticide material (chemical synthesis) technical product of pesticide (pesticide processing) pesticide preparation

  34. Concept of dispersing system and dispersing of pesticide. ★ Dispersing system of pesticide:solid/solid , liquid/liquid,solid/gas, liquid/gas and gas/gas dispersing system. ★ Concept of dispersing of pesticide: the dispersed grade of pesticide .

  35. Effect of enhancing pesticide dispersing on efficiency. Increase covering area. Enhance the quality of adherence of pesticide granule on processed surface. Change move quality of granule. Enhance surface tension. Enhance suspension and stabilization capability.

  36. Section 2 Adjuvants Class of adjuvants Fillers,carriers:kaolin, bentonite; Wetting agents:BX, detergent powder; Emulsifiers; Solvents:benzene, toluene; Dispersing agents: surface-active agents; Stickers: glutin; Stabilizers; Synergists: SV1.

  37. Structure and Effect of Surface-active agents Structure of surface-active agents (amphiphilic compound) Anionic surface-active agents Hydrophobic part Hydrophilic part Cationic surface-active agents Hydrophobic part Hydrophilic part

  38. Hydrophile-Lipophile Balance(HLB):A index to express the Hydrophile-Lipophile quality of surface-active agents,the higher of the HLB values,the more hydrophile of the SAA; on the contrary, the lower of the HLB values ,the more lipophile of the SAA.

  39. Surface-active phenomena

  40. Effect: Reduce surface tension Interface Air Liquid

  41. Make spray drop more fine

  42. Application in the processing of pesticide As emulsifiers used in emulsifiable concentrates. Oil water water Oil Oil

  43. As wetting agents used in wet table powders . Enhance the adherence ability of pesticide on sprayed surface.

  44. Class of surface-active agents Anionic SAA Cationic SAA:Organic amine Amphiphilic SAA:ester and aether Nonionic SAA Natural SAA

  45. Anionic SAA:Widely used, such as sodium dodecyl-benzene sulphonate, such as calcium dodecyl-benzene sulphonate. Sodium dodecyl-benzene sulphonate

  46. Section 3 Main Pesticide Formulation Dusts Granules Wet table powders Soluble powders Suspension concentrates and colloidal formulations Emulsifiable concentrates Seed coatings Oil solutions Controlled release formulations Smokes

  47. ◆ Dusts Constitute:Technical products and carriers. Standard:95% of pesticide can sieve through 0.074 µm mesh screen. Characteristic:easy to use;need no water;high efficiency. Shortcoming: pollute environment;bad control effects.

  48. ◆ Granules Constitute:Technical products,adjuvants and carriers. Classification:macrogranules;granules;microgranules. Standard:90% can match the standard of particle size; moisture content<3%. Characteristic:lower toxicity of high grade toxic pesticides in use;controlled release;easy to use; reduce pollution.

  49. ◆ Wettable powders Constitute:Technical products,wetting agents,dispersing agents and carriers. Classification:macrogranules;granules;micro granules. Standard: moisture content<3% ; pH=5~9; wetting time:1-2min;particle diameter:3~7 µm ;suspension rate:>70%. Characteristic:high develop quality.

  50. ◆ Soluble powders Constitute:Technical products,wetting agentsand carriers. Standard: moisture content<3% ; wetting time:2-3min. Should pay attention to distinguish the difference with wetting powders.

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