ORGANIC PEST MANAGEMENT

Submitted to

• Keshar Singh Solanki

Submitted by

• Dr. L.J. Desai

An

Assignment

on

General• Immense commercialisation of agriculture has had a

very negative effect on the environment. The use ofpesticides has led to enormous levels of chemicalbuild-up in our environment, in soil, water, air, inanimals and even in our own bodies. Fertilisers have ashort-term effect on productivity but a longer-termnegative effect on the environment where they remainfor years after leaching and running off, contaminatingground water and water bodies. The use of hybridseeds and the practice of monoculture has led to asevere threat to local and indigenous varieties, whosegermplasm can be lost for ever. All this for"productivity".

In the name of growing more to feed the earth, ithas taken the wrong road of unsustainability. Theeffects show - farmers committing suicide ingrowing numbers with every passing year; thehorrendous effects of pesticide sprays, pesticidecontaminated bottled water and aeratedbeverages are only some instances. The biggerpicture that rarely makes news however is thatmillions of people are still underfed, and wherethey do get enough to eat, the food they eat hasthe capability to eventually kill them.

Losses due to Pests

Insect pests, diseases and weeds are the major constraintslimiting agricultural productivity growth. It is estimated thatherbivorous insects eat about 26 percent of the potentialfood production. Emerging problems of insecticideresistance, secondary pest outbreak and resurgence furtheradd to the cost.India are estimated to be 18 percent of the agriculturaloutput. Losses caused by specific pests may be higher.Helicoverpa spp. in cotton causes losses up to 50 percent.According to Raheja and Tewari (1996), H. Armigera(American bollworm) alone causes an annual loss of aboutRs1000 crores.

• Another negative effect of this trend has been on the fortunes of the farming communities worldwide. Despite this so-called increased productivity, farmers in practically every country around the world have seen a downturn in their fortunes. This is where organic farming comes in. Organic farming has the capability to take care of each of these problems. Besides the obvious immediate and positive effects organic or natural farming has on the environment and quality of food, it also greatly helps a farmer to become selfsufficient in his requirements for agro-inputs and reduce his costs. Modern farming affects our world, by the way of land exhaustion, nitrate run off, soil erosion, soil compaction, loss of cultivated biodiversity, habitat destruction, contaminated food and destruction of traditional knowledge systems and traditions. Thus to overcome the ill effects of modern agriculture, can be delineated by adopting organic farming.

The production losses have shown an increasing trend overthe years. In 1983, the losses due to insect pests wereestimated worth ₨ 6,000 crores (Krishnamurthy Rao andMurthy, 1983), which increased to ₨ 20,000 crores in 1993(Jayaraj,1993) and to 29,000 crores in 1996 (Dhaliwal andArora, 1996). New pests have appeared due to the changesin the cropping patternsand the intensive agriculturalpractices.

Pest resistant varieties:

• Breeding for pest resistance is a continuous process. At the sametime the pests also, particularly the plant pathogens, co-evolve withtheir hosts. Thus, gene transfer technology is useful in developingcultivars resistant to insects, plant pathogens and herbicides. Anexample of this is the incorporation of genetic material fromBacillus thuringiensis (Bt), a naturally occurring bacterium, incotton, corn, and potatoes, which makes the plant tissues toxic tothe insect pests. Scientific community is impressed by its hugepotential in managing the pests, but is also concerned about thepossibility of increased selection pressure for resistance against itand its effects on non-target natural fauna. However, due to ethical,scientific and social considerations, this potential technology hasbeen surrounded by controversies.

Physical or mechanical controls

These are based on the knowledge of pest behaviour.• Placing plastic-lined trenches in potato fields to trap

migrating Colorado potato beetles is one example of thephysical control.

• Shaking of the pigeonpea plant to remove Helicoverpalarvae is a common practice in pigeonpea growing areas.

• Hand picking of insect pests is perhaps the simplest pestcontrol method.

• Installation of dead as well as live bird perches in cottonand chickpea fields has proved effective in checking thebollworm infestation.

• Using mulches to smother weeds and providing row coversto protect plants from insects are other examples.

Cultural pest controlIt includes crop production practices that make crop environment

less susceptible to pests. Crop rotation, fallowing, manipulation ofplanting and harvesting dates, manipulation of plant and rowspacing, and destruction of old crop debris are a few examples ofcultural methods that are used to manage the pests. Planting ofcover crops, nectar producing plants and inter-planting of differentcrops to provide habitat diversity to beneficial insects are importantmanagement techniques. Cover crops, often legume or grassspecies, prevent soil erosion and suppress weeds. A cover crop canalso be used as a green manure, which is incorporated in the soil toprovide nitrogen and organic matter to the subsequent crop. Whenincorporated in the soil, some cover crops of the Brassica familyhave the ability to suppress nematode pests and wilt diseases. Leftin the field as residues, rye and wheat provide more than 90percent weed suppression. Cultural controls are selected based onknowledge of pest biology and development.

Biological controls

These include augmentation and conservation of natural enemies ofpests such as insect predators, parasitoids, parasitic nematodes,fungi and bacteria. In IPM programmes, native natural enemypopulations are conserved, and non-native agents may be releasedwith utmost caution. Trichogramma spp. are the most popularparasitoids being applied on a number of host crops. A number ofmicroorganisms such as Trichoderma spp., Verticillium spp.,Aspergillus spp., Bacillus spp. And Pseudomonas spp. that attackand suppress the plant pathogens have been exploited as biologicalcontrol agents.

Estimated demand of different biopesticides to cover major crops

Bio-agents/Pheromones Demand to cover 50% of area

Trichoderma preparation 5000 tonnes

Trichogramma 4000 lakh cc

Helicoverpa NPV 4200 lakhs LE

Spodoptera NPV 19000 lakh LE

Helicoverpa pheromone trap 350 lakhs

Spodoptera pheromone trap 350 lakhs

REFERENCES

• http://anrcatalog.ucdavis.edu/pdf/7251.pdf