Agri dept to help farmers save maize from fall armyworm

Coimbatore: Farmers cultivating maize in Coimbatore and surrounding districts had to face a new problem last June - fall armyworm (spodoptera frugiperda). The insect, an invasive species native to the tropical and sub-tropical Americas that feeds voraciously on growing maize crops at its larva stage, had wreaked havoc in maize plantations.
According to the farmers, the pest causes the yield to drop by more than half per acre. “One acre of maize plantation would normally yield 3,500kg produce. After the fall armyworm attack, the harvest has reduced to around 1,500kg per acre,” said R M Palanisamy, a farmer. “Given that a quintal (00kg) maize is priced at Rs 1,900 in the market, the loses could be pegged at Rs 38,000 per acre.”

The farmers said the worm was found attacking the crop at its different growth stages. “On the 20th day of the crop, we found the worms feeding on the stalks. On the 45th day, we found the worms again. On a third instance, we found them feeding on the cobs,” Palanisamy said.

Though the farmers used insecticides, they were of no use. So, the agriculture department has pitched in to offer them a solution. The district agriculture department would soon give out an integrated pest control mechanism to control the fall armyworm. It would consist of a pheromone trap and a bio-control method. The pheromone trap would attract and trap the male adult insects, while the bio-control mechanism consists of the fungus Metarhizium anisopliae, which when sprayed would infect the larvae and kill them.

Researchers at the Tamil Nadu Agricultural University (TNAU) in the city said the studies have proved the efficacy of the two methods to fight the pest. N Muthukrishnan, head of department, agricultural entomology, TNAU, said the trap would consist of a chemical substance of composition of pheromone, a substance released by the female adult insect to attract male for reproduction. The adult males would be attracted by the scent of the chemical and be trapped. “When the insects hit the trap, they would fall into a funnel and would be collected in a bag,” Muthukrishnan said.

As for the fungus Metarhizium anisopliae, it would be given in powder form, which has to be mixed with water and sprayed on the crops. “The fungus will attack larvae and kill them. Also, as the fungus can multiply through spores, it would be effective even if sprayed once. The climate is also now conducive for the propagation of the fungus,” Muthukrishnan said.

S Banumathi, joint director of agriculture, Coimbatore, said they have sent a quotation for Rs 3.8lakh for providing the traps and Metarhizium to the farmers. “We will get them this week. We have advised the farmers to place five traps per acre,” she said.

While the pest attack was reported in nearly 2,000 acres (800 hectares) in around eight blocks in the district, almost half of the cultivated area has been harvested, Banumathi said. “We will provide pest control measures for around 1,100 acres.”