Rainfed rice - IRRI books - International Rice Research Institute

Insecticide Use, Precautions
and Insect Resistance
What are pesticides and insecticides?
P
esticides are the chemical compounds used to:
control pests (insects and diseases of plants);
minimise weeds;
kill pests and microorganisms that spoil agricultural products; and
control parasites and vectors of dangerous diseases of humans and
animals.
Insecticides, on the other hand, are the chemicals used particularly for
protecting plants and animals from harmful insects.
Initially, indigenous plant products such as Acorus calmus L. and neem;
wood preservatives such as coaltar and creosote; chrysallic acid, carbonic
acid; sanitary fluids – phenyl and crude oil emulsions; fish oil resin soaps,
Bordeaux mixture, lime, arsenic, copper salts and many others were used.
When and how to use pesticide control measures
Users should possess knowledge of the pests that have to be controlled, the
physical properties of insecticides and the influence of weather and plant
growth on their effectiveness. Pesticides should be used only when the pests
occur above economic threshold or economic injury levels. This will not only
reduce the cost of control measures but also reduce pesticide-related
pollution.
When to avoid pesticide control
Avoid prophylactic measures and
repetitions of the same’ insecticides
against the same pest.
If natural enemies are high,
insecticidal control is not necessary.
Avoid application when wind
velocity is high to avoid excessive
drifting and also when the
population and activities of non-
target organisms, such as honeybees,
etc., are high.
Chemical formulations
The successful use of pesticides depends
not on their toxicity alone but also, to a
considerable extent, on the form of
pesticides. The formulation determines how
a pesticide is used. The pesticides normally
used to control insect pests are available as
powders (dust), granules, solutions,
emulsifiable concentrates, ultra-lowvolume
concentrates and as aerosols and
fumigants. Some of these pesticides are also
available as poison baits, insecticide soaps,
paints and insecticide papers.
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