Pesticide Use in India
Vegetables are important component of Indian agriculture. Diverse agroclimatic conditions of the country permit growing of several vegetables round the year. Among these potato, tomato, onion, brinjal, cabbage, cauliflower and okra are most important and they have major share in vegetable production . Presently, India produces about 156.33 million tonnes of vegetables from an area of 8.99 million hectares with an average productivity of 17.4 t/ha. Though there has been a phenomenal increase in area (2.99 folds), production (8.88 folds) and productivity (2.96 folds) of vegetables in our country during the last 6 decades, still there is a huge gap between present production and future requirements.This necessitates enhancing vegetable production for meeting current and future needs.
One of the major constraints in vegetable production is pest problem and crop losses in the country due to various pests range from 10 to 30 percent each year depending upon the severity of pest attack. The estimated loss due to pests in horticultural crops is approximately Rs. 40,000-50,000 crores. Pest control by use of chemicals has been playing a vital role in sustainable increase in the vegetable production. Farmers use pesticides as first line of defense for the management of pests and frequently resort to indiscriminate and non-judicious use of pesticides, which leads to several problems such as resistant development in insects / pathogens, resurgence of pests due to destruction of natural enemies, toxic hazards due to pesticide residues on the edible products and deficient pollination due to destruction of pollinators resulting in non setting of fruits and low yields.
Pesticide consumption in India and other countries
In developed countries like USA, Europe, Japan, China, etc., pesticide use is 20 times more than in India. Per hectare consumption of pesticide in India is 381 g a.i./ha which is lower than the world average of 500 g a.i/ha. Lower consumption of pesticides in India can be attributed to the fragmented land holdings, dependence on monsoons, inadequate awareness among farmers and low investment capabilities of small and marginal farmers. Only 25-30 percent of the total cultivated area in the country is under pesticide cover.
In India, annual consumption of pesticides showed a rising trend from 1955-56 to 1990-91 and thereafter it started declining . The present consumption of technical grade pesticides in the country during year 2010-11 is around 55,542 tonnes. India’s consumption of pesticides is only 2 percent of the total world consumption. Several reasons could be ascribed to this trend including the new eco-friendly novel molecules, where the quantities of newer pesticide molecules required per unit area are almost 8-100 times less than the conventional molecules.
Among different classes of pesticides used in India the percent share of insecticides (60%) is high followed by fungicides (19%), herbicides (16%), biopesticides (3%) and others (3%). It is estimated that around 13-14 % of total pesticides used in the country are applied on vegetables, of which insecticides account.For two-thirds of total pesticides used in vegetables (Figure 5). Among different vegetable crops the maximum pesticide usage is in chilli (5.13 a.i kg /ha) followed by brinjal (4.60 a.i kg /ha), Cole crops (3.73 a.i kg /ha) and okra (2-3 a.i kg /ha) . The
global agrochemical consumption, on the other hand, is dominated by fruits and vegetables, which account for 25% of the total market.
Role of novel molecules in pest management
During last two decades the focus on insecticide research shifted to search and develop new green chemistries or newer bio-rational or “low risk” pesticides having novel modes of action, which have replaced many old and conventional pesticides. Biorational or “reduced risk” insecticides are synthetic or natural compounds that effectively control insect pests, but have low toxicity to nontarget organisms and the environment (Hara, 2000).
In India, around 27 new insecticides and their different formulations belonging to new chemistry with a unique mode of action have been registered since the late 1990s to early 2010, for insect control in vegetables. These new classes of insecticides belong to neonicotinoids, oxadiazines, diamides, tetramic/tetronic acid derivatives, phenylpyrazoles, pyridine, avermectins, spinosyns, pyrroles and insect growth regulators (IGRs). Most of the newer insecticides have several advantages over conventional insecticides like:
• greater specificity to target pests
• excellent efficacy at low rates or dosage
• high level of selectivity
• Non-persistence in the environment
• low mammalian toxicity
• less harmfull to natural enemies than another broad spectrum
• less likely to cause outbreaks of secondary pests that are well controlled by natural enemies
• extremely helpful for delaying development of resistance in key pests and have no cross-resistance with the old and already established insecticides.
All these advantages make many of the new insecticides safer, highly suitable and fit well into integrated pest management (IPM) or insect resistance management (IRM) programs. As growers and pest control advisors become familiar and aware of unique characteristics, novel mode of action, usage rates, their target pest spectrum and selectivity of these new insecticides, their adoption and judicious use is likely to increase.
- Indian Institute of Vegetable Research, Varanasi