Lecture 25 : PESTICIDE COMPATIBILITY
- In pest control treatment, two or more pesticides, fungicides or even fertilizers are
sprayed or applied in the same operation to minimize cost of labour.
- Before mixing two different chemicals, their physical and chemical properties
should be well understood.
- Incompatible pesticides should not be mixed. Only compatible pesticides can be
mixed.
Incompatability of pesticides may be of following types
a. Chemical incompatibility
Chemical compounds in the two pesticides react with the another producing a
different compound, reducing the pesticidal activity of the pesticides (Degradation of
active ingredient).
b. Biological incompatibility (Phytotoxic incompatibility)
The mixed product exhibit phytotoxic action, which independantly is not
phytotoxic.
c. Physical incompatibility
The physical form of the pesticides change, and one of them become unstable
or hazardous for application (agglomeration, phase separation, explosive reaction,
etc.).
HAZARDS CAUSED BY PESTICIDES
The adverse effect caused by pesticides to human beings during manufacture,
formulation, application and also consumption of treated products is termed as the
hazard.
Pesticide hazard occurs at the time of
a. Manufacturing and formulation
b. Application of pesticides
c. Consumption of treated products
Examples of hazards caused by pesticides
1. In Kerala, in 1953, 108 people died due to parathion poisoning
2. ‘Bhopal Gas Tradedy’ in 1984 at Bhopal where the gas called Methyl isocyanate
(MIC) (an intermediate involved in manufacture of carbaryl) leaked killing 5000
people and disabling 50,000 people. Totally 2,00,000 persons were affected.
Long term effects like mutagenic and carinogenic effects are felt by survivors.
3. Cases of Blindness, Cancer, Liver and Nervous system diseases in cotton growing
areas of Maharashtra where pesticides are used in high quantity.
4. Psychological symptoms like anxiety, sleep disturbance, depression, severe head
ache in workers involved in spraying DDT, malathion regularly.
, 5. Endosulfan - causing problem due to aerial spraying in cashew in Kerala - recent
controversy - yet to be studied in detail.
Safe handling of pesticides
1. Storage of pesticides :
a) Store house should be away from population areas, wells, domestic water
storage, tanks.
b) All pesticides should be stored in their original labeled containers in tightly
sealed condition.
c) Store away from the reach of children, away from flames and keep them under
lock and key.
2. Personal protective equipment
a) Protective clothing that covers arms, legs, nose and head to protect the skin.
b) Gloves and boots to protect hands and feet.
c) Helmets, goggles and facemask to protect hair, eyes and nose.
d) Respirator to avoid breathing dusts, mists and vapour.
3. Safety in application of pesticides
Safe handling of pesticides (Fig.68) involves proper selection and careful
handling during mixing and application.
a) Pesticide selection : Selection of a pesticide depend on the type of pest,
damage, losses caused, cost etc.
b) Safety before application :
i. Read the label and leaflet carefully.
ii. Calculate the required quantity of pesticides.
iii. Wear protective clothing and equipment before handling.
iv. Avoid spillage and prepare spray fluid in well ventilated area.
v. Stand in the direction of the wind on back when mixing pesticides.
vi. Do not eat, drink or smoke during mixing.
vii. Dispose off the containers immediately after use.
c) Safety during application
i. Wear protective clothing and equipment.
ii. Spray should be done in windward direction.
iii. Apply correct coverage.
iv. Do not blow, suck or apply mouth to any spray nozzle.
v. Check the spray equipment before use for any leakage.
d) Safety after application
i. Empty the spray tank completely after spraying.
- In pest control treatment, two or more pesticides, fungicides or even fertilizers are
sprayed or applied in the same operation to minimize cost of labour.
- Before mixing two different chemicals, their physical and chemical properties
should be well understood.
- Incompatible pesticides should not be mixed. Only compatible pesticides can be
mixed.
Incompatability of pesticides may be of following types
a. Chemical incompatibility
Chemical compounds in the two pesticides react with the another producing a
different compound, reducing the pesticidal activity of the pesticides (Degradation of
active ingredient).
b. Biological incompatibility (Phytotoxic incompatibility)
The mixed product exhibit phytotoxic action, which independantly is not
phytotoxic.
c. Physical incompatibility
The physical form of the pesticides change, and one of them become unstable
or hazardous for application (agglomeration, phase separation, explosive reaction,
etc.).
HAZARDS CAUSED BY PESTICIDES
The adverse effect caused by pesticides to human beings during manufacture,
formulation, application and also consumption of treated products is termed as the
hazard.
Pesticide hazard occurs at the time of
a. Manufacturing and formulation
b. Application of pesticides
c. Consumption of treated products
Examples of hazards caused by pesticides
1. In Kerala, in 1953, 108 people died due to parathion poisoning
2. ‘Bhopal Gas Tradedy’ in 1984 at Bhopal where the gas called Methyl isocyanate
(MIC) (an intermediate involved in manufacture of carbaryl) leaked killing 5000
people and disabling 50,000 people. Totally 2,00,000 persons were affected.
Long term effects like mutagenic and carinogenic effects are felt by survivors.
3. Cases of Blindness, Cancer, Liver and Nervous system diseases in cotton growing
areas of Maharashtra where pesticides are used in high quantity.
4. Psychological symptoms like anxiety, sleep disturbance, depression, severe head
ache in workers involved in spraying DDT, malathion regularly.
, 5. Endosulfan - causing problem due to aerial spraying in cashew in Kerala - recent
controversy - yet to be studied in detail.
Safe handling of pesticides
1. Storage of pesticides :
a) Store house should be away from population areas, wells, domestic water
storage, tanks.
b) All pesticides should be stored in their original labeled containers in tightly
sealed condition.
c) Store away from the reach of children, away from flames and keep them under
lock and key.
2. Personal protective equipment
a) Protective clothing that covers arms, legs, nose and head to protect the skin.
b) Gloves and boots to protect hands and feet.
c) Helmets, goggles and facemask to protect hair, eyes and nose.
d) Respirator to avoid breathing dusts, mists and vapour.
3. Safety in application of pesticides
Safe handling of pesticides (Fig.68) involves proper selection and careful
handling during mixing and application.
a) Pesticide selection : Selection of a pesticide depend on the type of pest,
damage, losses caused, cost etc.
b) Safety before application :
i. Read the label and leaflet carefully.
ii. Calculate the required quantity of pesticides.
iii. Wear protective clothing and equipment before handling.
iv. Avoid spillage and prepare spray fluid in well ventilated area.
v. Stand in the direction of the wind on back when mixing pesticides.
vi. Do not eat, drink or smoke during mixing.
vii. Dispose off the containers immediately after use.
c) Safety during application
i. Wear protective clothing and equipment.
ii. Spray should be done in windward direction.
iii. Apply correct coverage.
iv. Do not blow, suck or apply mouth to any spray nozzle.
v. Check the spray equipment before use for any leakage.
d) Safety after application
i. Empty the spray tank completely after spraying.
