All about potatoes.pdf - Vegetableipmasia.org

6.
INSECT ECOLOGY
water or may already be dissolved in an organic solvent (alcohol for example)
making them water-soluble. The consistency and color of these pesticides are
similar to EC, but become clear after being diluted with water. The important
components in these formulations are active ingredients and organic solvents.
Solvents used are types of alcohol.
• Wettable powder (WP): WP contains active ingredients, a wetting agent and other
materials such as adhesives. The wetting agent allows an even mixture of powder
and water when it is diluted for spraying. Without the wetting agent, the active
ingredients would not mix with water, but float on the surface. Carriers are
generally in the form of mineral powder such as talc or clay. This talc or clay
settles at the bottom of the tank and needs continuous shaking to maintain
suspension.
• Flowable (F): In these formulations, active ingredients are mixed with a carrier (a
mineral powder) and a small amount of water producing a formulation fine but wet
granules. This "wet mixture" is easy to mix evenly with water and can be sprayed
using the same type of sprayers as used for WP formulations. This formulation
requires continuous stirring.
• Soluble Powder (SP): Active ingredients in SP formulations are either in a powder
form that dissolves in water or formed into pellets containing small amounts of
wetting agent to increase water solubility. Different from WP and F formulations,
SP formulations do not require continuous stirring when spraying as the mixture
remains in continual suspension.
• Granules (G): The components of this formulation are an active ingredient, carrier
and adhesive. This mix of materials is made into small granules. Active
ingredients make up around 2-25%. Carriers are clay and mineral substances.
Based on their mode of action:
• Contact pesticides: There are pesticides that kill their intended targets by coming
into contact with them. These pesticides remain on plants just after application,
but are generally only effective for short periods of time and are easily affected by
weather factors, particularly temperature and sunlight. They must be applied
directly to the plant parts where pests and diseases are often found.
• Systemic pesticides: These are pesticides that can enter and spread through all
parts of a plant and affect the pest or disease after it consumes plant parts.
Systemic insecticides generally poison stomachs or nerves, and are effective for
controlling pests that suck, eat plant tissue or bore. Spraying needs not
necessarily be on the affected parts of plants as these pesticides spread to all
parts including the roots. Toxicity of these pesticides is generally long-lasting.
These should not be used before harvesting as they can pollute crop produce and
pose toxicity hazards to consumers.
C. Pesticide toxicity classification
The WHO (World Health Organization) has classified pesticides based on their
toxicity. Pesticide classes depend on how hazardous they are to humans:
• EXTREMELY HAZARDOUS (Class Ia): Pesticide formulations with, for example,
the active ingredients parathion-methyl, mevinphos, alachlor.
• HIGHLY HAZARDOUS: (Class Ib) Pesticide formulations such as those containing
the active ingredients methamidophos, edifenphos, dichlorvos, monocrotophos, or
methomyl.
• MODERATELY HAZARDOUS (Class II): Pesticide formulations with the active
ingredients ofatox, dimethoate, cypermethrin, fenvalerate, deltamethrin,
fenobucarb, cartap, fipronil, endosulfan, fluvalinate and paraquat.
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ALL ABOUT POTATOES