Management of insect-pest in organic agriculture
Authors: Roop Singh, Irfan Khan, Ashok Kumar Malav, Kuldeep Singh Chandrawat and M. K. Yadav
Ph.D. Scholars, Maharana Pratap University of Agriculture and Technology, Udaipur (Rajasthan) 313001
Organic agriculture is “Ecological production management system that promotes and enhances bio-diversity, biological cycles, and soil biological activity approaches based on minimal use of off-farm inputs ecological harmony”.
Strategies for managing pests in organic agriculture
(I) Insect avoidance techniques
To manage the insect-pest populations effectively, producers need to understand the biology and growth habits of both pest and crop.
(a) Crop rotation
It is an extremely effective way to minimize most pest problems while maintaining and enhancing soil structure and fertility. Crop isolation/rotation strategies are most effective against pests that do not disperse over great distances and/or that overwinter in or near host crop fields. Examples; Rotation with glucosinolate-containing brassicaceae can be beneficial through biofumigation effects against soil-borne pests and diseases.
(b) Field sanitation
Insects most affected by field sanitation will be those that overwinter in crop residue. Examples; the alfalfa plant bug is controlled by burning crop residues in early spring and also effective against fruit fly management.
(c) Seed quality
Planting physically sound seed is important. In crops such as flax, rye and pulses, a crack in the seed coat may serve as an entry point for soil-borne micro-organisms that rot the seed once it is planted.
(II) Managing the Plant Growth Environment
(a) Soil quality management
Enhancement of soil fertility accomplished through rotations, cover cropping, and the application of plant and animal materials.
Intercropping can reduce pest problems by making it more difficult for the pests to find a host crop. Intercropping of spinach beans and tomato reduced the incidence of cabbage aphid and DBM in cabbage crop. Incidence of pod borer (H. armigera) reduced in chickpea when grown in association with barley, mustard, linseed and coriander.
(c) Mixed cropping
Mixed cropping reduces the concentration of suitable food plants for insects that specialise on a subset of the plants or varieties grown in the mixture.
(d) Time of sowing
The susceptible time of plant growth does not correspond to the peak in pest cycles. Early sowing of cereal crops reduced grasshopper and aphid populations while late sowing of cereal crops reduced the wireworms and cutworms.
(e) Depth of sowing
For most crops, seeding should ideally be done when the soil is warm enough for rapid germination. Seeds that remain ungerminated in cool soil are more susceptible to damage by insects such as wireworms.
Tillage should be properly timed before seeding, after harvesting and during summer fallow to reduce populations of insect pests such as cutworms and grasshoppers. Tillage after rice harvest kills stem borers, armyworm pupae, grasshopper eggs, black bugs and root weevils.
Different types of mulches such as, organic mulch, straw mulch suppress insects in comparison to bare soil.
(h) Trap crop
Trap crops attract pest species away from the cash crop to be protected and into a specific area where they can be destroyed. The trap crops can be planted with or around the perimeter of the cash crop field. Marigold and okra is a trap crop in cotton fields for H. armigera and pod borers respectively.
(III) Direct treatment
Insect monitoring traps are useful in determining which insect pests are present in a field and whether they are at economically important levels. Pheromones and other chemical attractants can be used as monitoring, disrupt matting and mass trapping. Some important pheromones and their target pest.
Pheromones - Target Pest
Helicure - Tomato fruit borer
DBM lure - Diamond back moth
Fly T - Fruit fly
(b) Biological control
Organic crop production relies on the suppression of pests through the introduction, conservation or enhancement, or augmentation of predators (or parasitoids).
(c) Natural insecticides
Some botanicals have broad spectrum properties such as, repellant, knock down, anti-feedant which is effective in controlling the insect- pest. Extracts of chilli pepper in mixture with garlic (Allium sativum L.), onion (Allium cepa L.) bulbs extracts and lemon grass (Cymbopogon citrates Staph.) leaf extract: very effective against some leaf eating insect pests of crops.
(4) Other formulations
Other bioformulations viz; cow urine, fermented butter milk, tamara lassi are also effective against controlling pest populations.
About Author / Additional Info:
I am currently pursuing Ph.D. in Plant Pathology from MPUA&T, Udaipur.