According to a study published in the Indian Journal of Entomology, insect pests on an average cause up to 20% yield loss in the main crops. There are many approaches to pest management and ecological engineering is one of them. 

What is ecological engineering?

It is a unique approach that relies on cultural techniques which draw from local ecological knowledge rather than ‘external’ and synthetic approaches. Think of it this way: use a natural enemy of the local pest rather than spraying chemical pesticides on crops.

Take for instance, the case of paddy farmers in Erode, Tamil Nadu, India. Pests such as gall midge, rice thrips and leaf folder cause around 30% yield loss every year. The farmers relied on pesticides but this caused soil deterioration. The National Institute of Plant Health Management (NIPHM), Hyderabad introduced ecological engineering which eliminated chemical sprays. 

The result was a 50% reduction in pest population along with cost savings because of doing away with chemicals. The concept is now being tried out on different crops and in different locations as well. 

How does ecological engineering work?

Every field ‘lives’ in a particular ecosystem which has abiotic (non-living chemical or physical) and biotic (living organisms) components. NIPHM talks of starting the ecological engineering process by doing an analysis of these two components and then:

• Planning a crop-specific approach to pest management
• Trains framers on managing the habitat so there is better biological control 
• Integrating nutrient management with soil fertility and
• Fostering natural enemies - biocontrol agents - to control and eliminate pests

Agro ecosystem analysis or AESA is a keystone in ecological engineering. AESA helps identify pests, when and where they occur, monitor plant health and incorporates the farmer’s historic knowledge as well. 

Tools of ecological engineering

Broadly speaking, ecological engineering relies on biological control for pest management. This simply means using the right biofertilizer and the right natural predator of the pest. For instance, crops that are over-fertilized with nitrogen can be vulnerable to white flies and aphids. 

Ecological engineering also deploys the following to take care of pests naturally:

• Rhizosphere Engineering
• Parasitoids predators
• Using mycorrhiza 
• Microbial biopesticides to name a few.

These tools rely on the P:D ratio or the Pest: Defender ratio and help the farmers decide on the technique to be deployed on their field. 

For instance, microbial biopesticides are microorganisms like different bacteria which act against invertebrate pests. Mycorrhiza refers to a symbiotic relationship between a plant and a fungus which allows for healthier root systems. Parasitoids predators are insects and worms such as wasps and spiders. Natural enemies of a pest help in population control. For instance, ladybird beetles attack aphids. Rhizosphere engineering is the manipulation of the population of microorganisms in the very narrow zone of soil (rhizosphere) lying next to the roots of a plant.

Perhaps one of the biggest challenges faced by ecological engineering is the time frame. Quick fixes like chemical pesticides may bring the desired effect immediately but may cause long-term damage. And this would be the biggest reason why smart farmers will choose smart solutions like ecological engineering.