Few tips for farmers on using pesticides in crop fields

Dr Arup Kumar Sarma and Ranjita Parashar *

Chemical pesticides are an integral part of modern agriculture. Pesticides are mainly used to control the harmful insect - pests, mites, weeds, rodents and diseases of crops. However, often these are applied in overdose by farmers to get quick control. Overdose of pesticides leads to residual problem and also reduce the quality of harvests besides polluting the environment (soil, water and air).

Moreover, continuous use of overdose of pesticides for several years may lead to such a situation that even that very overdose fails to give adequate control on targeted pests. The pests, which had been recognized as minor one for decades, appear as major problem causing huge crop loss. The management of such pests becomes more and more difficult.

Under such situation the cost of production increases and consequently the profit decreases. Moreover, hazards may occur at any point of time of preparation of spray solution, application and there after too if proper care is not taken. Pesticide poisoning is the consequence of ignorance to such “Do’s and Don’ts”.

Every person associated with farming and handling of pesticides should look into the following simple steps to avoid such hazards of pesticides. It is also their responsibility to maintain the residue level below the acceptable daily intake (ADI) so that general public as consumer of agro-products remains safe.

* It is better NOT to use any chemical pesticide in the crop field to extent possible. The attitude should not be to eradicate or eliminate any pest (insect, mite, rodent, weed etc.) from crop-field as soon as they are noticed.

* The pests are also a part of our agro-ecosystem and should not be controlled unless they become harmful economically. The minimum number of a pest species which causes economic injury to crop is called Economic Injury Level (EIL). Applying any chemical pesticides beyond EIL is not profitable.

Pesticide application should be initiated at a point of time that can prevent the increasing pest population before reaching the EIL. This is called Economic Threshold Level (ETL). EILs and ETLs of different pests which have been determined by the agricultural scientists already for a crop ecosystem.

Farmers should get the information from extension officers, extension workers (Gramsewak), Agriculture Extension Assistants (AEAs) and agro-based NGOs in order to know the right time of pesticide application. Application done after or before the right time leads to wastage of pesticides and failure in pest control.

* Farmers may recognize the insect- pest/disease to be controlled. If not recognizable for him, he should collect the sample of such pests and consult agricultural scientists/officers and other agricultural extension workers. The control measure should be taken according to their advice only.

* A wide variety of chemical pesticides available in the market. It should be noted that all of these are not equally effective. A farmer should ensure that the pesticide he is buying will be able to control his target pest. He should buy only those chemical pesticides which are recommended by agricultural scientists and extension officers. They should be used it in recommended dosage only. Do not buy and apply any chemical pesticide as per the advice of pesticide retailer or shopkeepers.

* A farmer should buy pesticide from a government agency or government registered shop or authorized dealer. While buying it is mandatory to see the level of the pesticides content, date of manufacture and expiry date. Applying pesticide beyond expiry date may lead to poor control of pest which has direct influence on crop yield.

* Every pesticide is poisonous and hence, farmers should be well aware of its nature of poisoning and reaction time before its application. Ignorance on it may lead to faulty application of these poisonous chemicals which may result in ill-effects on the crop (Phytotoxicity), crop-pollinators (like bee, butterfly etc.), natural enemies of pests, animals grazing on field, fish and other aquatic lives nearby the site of application.

The preliminary information of poison level and reaction time of pesticides can be derived from the colour of the triangle drawn on the outer surface of the container. If it is of red colour, the pesticide is extremely poisonous and reacts very quickly and should be handled with the utmost care.

Pesticides with yellow triangle are highly toxic and those with blue triangle are moderately toxic, whereas, the pesticide with green triangle is relatively less poisonous. Whatever may be the poison level of pesticide, it should be handled with extra care. One should not take it casually; because, carelessness may lead to fatal accidents. These should be kept in a place out of reach for children.

* If someone gets poisoned by pesticides, it is essential to consult a doctor as soon as possible. However, the information on first-aid is sometimes written on the pesticide container or leaf-let inside. Follow the instructions.

* The empty containers of pesticides after use should not be thrown here and there, but should be burnt in an isolated place. Such empty container should never be used for keeping/preserving food items.

* The persons engaged in pesticide application should take utmost care and safety measures. During application he should used gloves, mask, goggles and a dress covering the entire body. He should not take any food and drinks during pesticide application. Nails should be cut and bathing with soap after application is must. While bathing keep the eyes closed initially for a few minutes to avoid splash on eyes. Clothes, gloves etc. should be washed and dried after use.

* Pesticide application should be done during calm evening hours in sunny days. Avoid application in morning hours to save the pollinators viz. bees and butterflies. In urgent cases, it can be applied in windy days too, but with more precautions. In such situation, keep the backside of your body toward wind’s direction; start spraying from end of the crop field and move backward step by step to other end. Keep the spray nozzle close to targeted plant parts to avoid undue drift.

* The container where the pesticide is diluted (bucket or spray tank) should be washed off thoroughly so that even a trace of chemical is not adhered to it. Such container should not be washed in a pond which is in use for fishery purpose.

* When the same sprayer is used for applying two pesticides, spray them one after another. Intermixing of two pesticides may result in serious consequences. Hence, the sprayer should be washed thoroughly after applying one pesticide to make it ready for the next one.

* A considerable time-gap should be maintained between the last application of pesticide and harvest of crop to avoid consumption of residues chemical.

* The hazards and the ill-effects associated with pesticide use are well-known today. Hence, instead of sole dependence on chemical pesticides emphasis has been given on Integrated Pest Management (IPM) where different control tactics are judiciously integrated to maintain ecological harmony.

In biological control, the natural enemies (predator, parasite and pathogen) are collected from natural habitat of the pest and then mass multiplied and released on crop to control the pests. Though it is a slow control tactic it is free of hazards and ill-effects associated with chemical pesticides. Therefore, care should be taken to preserve and not to harm such natural enemies while applying pesticides.