Transition to organic farming : Pest and disease management

Rebecca Lalbiakngheti Ralte
Conventional agricultural systems increase food production per acre 0.4ha but can deplete natural resources and degrade crop and environmental health. By implementing organic farming as an alternative production system, growers may substitute cultural and biological inputs for synthetically-made chemicals and fertilizers that still provide effective pest and disease management.
In fact, most insects–on agricultural land are actually beneficial. Beneficial insects prey on the pests whose favourite foods happen to be the cash crops. Different plants attract different insects, so encouraging a diversity of plant species beyond cash crops can shift the balance away from pest insects. Diversity encourages a healthy and resilient system.
In general, improving soil quality and encouraging beneficial organisms will help reduce pest populations and prevent disease. Gypsum, dolomite, and potassium magnesium sulphate can correct plant nutrient deficiencies or imbalances, raise soil pH, leach out excess exchangeable sodium by calcium replacement, and improve soil water infiltration. Beneficial insects such as green lacewing, lady beetle, and syrphid feed on many soft-bodied insect pests such as aphids, mites, whiteflies, thrips and some larvae.
. Select land with high nutrient status, good soil structure and low pest and disease pressure if possible.
· In the first year, plant a crop less reliant on nitrogen to offset some problems associated with low soil N.
· Design a crop rotation with pest-resistant leguminous cash or cover crops to supply N (such as faba bean, hairy vetch and crimson clover), reduce pest populations and enhance soil organic matter.
· Select crops (such as buckwheat, dill, oregano, thyme, red cosmos, yarrow, marigold) that attract beneficial organisms (such as lady beetles, spiders, lacewings, arthropods, millipedes, and honey bees) both above the soil surface and underground.
· Routinely incorporate green manure and compost in your cropping system to increase soil organic matter, improve water infiltration and reduce soil erosion.
· Alternate cold-season crops with warm-season crops to interrupt pest and disease cycles.
· Choose reduced or no-cultivation techniques that are practical and economical, such as using a high-residue cultivator and roller-crimper.
· Manipulate planting dates. For example, plant immediately after bed cultivation and/or bed preparation to allow establishment of crop plants before re-growth of weeds and to potentially break insect life cycles.
· Use pest-free stocks and pest and disease resistant crop varieties.
· Scout and trap using insect pheromones.
· Use soil solarization in regions with warm and sunny climate to reduce soil borne pathogens and other pests.
The writer is with KVK, Aizawl, CAU, Mizoram For further details contact PR & Media Management Cell, CAU, Imphal.