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Wednesday, December 11, 2019

Fall armyworm: An insect that can travel 100 km per night & the threat it poses for farmers

Given its ability to feed on multiple crops — nearly 80 different crops ranging from maize to sugarcane — FAW can attack multiple crops. Similarly, it can spread across large tracts of land as it can fly over large distances. This explains the quick spread of the pest across India.

Written by Parthasarathi Biswas | Pune | Published: May 5, 2019 7:27:16 am
Fall armyworm: An insect that can travel 100 km per night & the threat it poses for farmers A maize farmer with his harvested crop near Purnea, Bihar. Prashant Ravi Entomologist Sharanabasappa Deshmukh with a pheromone trap to track fall armyworm buildup at a maize research field in Shivamogga, Karnataka. (Express Photo)

First reported in India last year, the Fall Armyworm (FAW) or Spodoptera frugiperda has become a major problem for farmers this year, with the pest hitting the production of the crop.

More than 50 per cent of the country, including Mizoram, has reported cases of FAW infestation this year. Ahead of the new kharif season, FAW poses a serious challenge before farmers due to lack of knowledge about the pest and lack of clarity on how to tackle it. If these problems are not addressed urgently, vast tracts of crops can be laid to waste by this pest.

What is FAW?

A native of the tropical and sub-tropical regions of the Americas, FAW was first detected in the African continent in 2016. Since then, it has spread to other countries such as China, Thailand, Malaysia and Sri Lanka. It was reported in India for the first time last year, when it affected crops in Karnataka. Within a span of only six months, almost 50 per cent of the country, including Mizoram, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh, Chhattisgarh, Madhya Pradesh, Gujarat and West Bengal, has reported FAW infestations.

In its 45-day-long lifecycle, the female moth of this pest lays around 1,500-2,000 eggs on the top of leaves. In the roughly 30-day larval stage, the caterpillar goes through six stages of development or instars.This is the most dangerous part of the lifecycle as the caterpillar feeds on leaves, whorls, stalks and flowers of crop plants. Once this stage is completed, the growing moth pupates in the soil — for 8-9 days in summer and 20-30 days in cold weather. The nocturnal egg-laying adults live for about 10 days, during which they migrate long distances.

Also Read | Pest challenge: A new, unwelcome visitor

What makes FAW dangerous is the polyphagous (ability to feed on different kinds of food) nature of the caterpillar and the ability of the adult moth to fly more than 100 km per night.

Given its ability to feed on multiple crops — nearly 80 different crops ranging from maize to sugarcane — FAW can attack multiple crops. Similarly, it can spread across large tracts of land as it can fly over large distances. This explains the quick spread of the pest across India.

How FAW affects output

Till date, India has reported FAW infestation on maize, sorghum (jowar) and sugarcane crops. Maize has been the worst affected as most maize-growing states in southern India have been affected by the pest. FAW infestation and drought has led to a shortfall of nearly 5 lakh tonnes in output, prompting the central government to allow import of maize under concessional duty. Maize is the third most important cereal crop grown in the country and the infestation, if not checked in time, can wreck havoc.

Difficulties in controlling infestation

The Central Insecticide Board and Registration Committee (CIBRC) — which recommends usage of pesticides during infestations — is yet to come up with recommendations to control the spread of FAW as the pest is still relatively unknown in these parts.

Last year, as reports of FAW infestations started pouring in from across the country, the CIBRC had allowed spraying of select insecticides/formulations — Carbofuran, Phorate, Thiamethoxam (12.6%) plus Lambda-cyhalothrin (9.5%), and Chlorantraniliprole 18.5% suspension concentrate — on a trial basis. The sanction has since lapsed although the CIBRC has formed a committee to come up with such ad-hoc recommendations.

Most entomologists have suggested the Integrated Pest Management system to control the pest. This would involve constant surveillance of the pest during its vegetative growth phase and taking measures like mechanically destroying the egg masses and using pheromone traps to catch the insects. Pheromone traps are devices which are used to attract male insects by luring them with female pheromones. Farmers should also be discouraged from taking up staggered sowing, as this would allow the pest to have multiple reservations for growth.

What the govt is doing

Dissemination of information is one of the most potent tools to control the spread of the pest. The Maharashtra government’s department of agriculture is also keeping a close watch on the situation and has sounded the high alert about FAW.

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