Common birds are effective bio-pest controllers

The unprecedented invasion of rice swarming caterpillar (armyworm) on the State’s paddy fields has brought to the focus the role of common birds as effective bio-pest controllers, with experts calling for innovative measures to attract more omnivorous birds to cropland.

This is necessary as there has been a diminishing presence of birds across cropland due to the practice of cutting down of roosting trees in and around agricultural lands whereas providing adequate space for the birds that can be an effective weapon to fight the pest menace.

“A large variety of birds dominating our agricultural landscape are voracious worm eaters and help maintain the worm population at the economic threshold level. These common birds are effective bio-pest controllers – including against pests that have developed immunity to chemical pesticides. Unfortunately, depletion of roosting space has resulted in their waning presence in our paddy fields,” Dr Prabal Saikia, Principal Scientist, Agricultural Ornithology and Entomology, Assam Agricultural University (AAU), told The Assam Tribune.

Dr Saikia said that even today, birds, particularly the familiar species such as common mynah and egrets, were providing a lot of succour to the harrowed farmers by devouring the armyworms in large quantities.

“Many of our farmers are ignorant about the important role played by birds in controlling insects and rodents. For attracting birds, trees and shrubs that give them roosting space should be grown in and around cropland. Earlier, our paddy fields used to have simul and other trees in sufficient numbers, but these have been insensitively cut down,” he added.

According to Dr Saikia, small trees like jamlaphuti, phutkola, helos, etc., that grow easily near cropland should be planted to attract birds. Moreover, innovative and low-cost methods such as erecting T-shaped perches can attract birds to feed on worms and rodents. “Our experience has shown that perches can attract wide ranging insect-eaters in good numbers. This can be an effective and sustainable pest-control solution,” he said.

According to a report of the All India Network Project on Agricultural Ornithology covering North Bank landscape, i.e. Sonitpur, Darrang, Lakhimpur and Dhemaji districts (plain zone) conducted by AAU, as many as 96 species of birds occurred in the area’s agricultural landscape of which a majority were found to be effective against pests. Again, 58.3 per cent of the birds occurring in agricultural landscape were found in paddy fields, with 49 of those being common/resident species.

“With some simple techniques, the scope for utilising beneficial birds for suppression of insects, worms and rodents can be increased manifold. Our study found a total of 11 bird species utilising the T-perches in the fields. The highest number of nine species were recorded in September – coinciding with higher pest prevalence,” he said.

“The frequent visitors were black drongo and pied mynah. Black drongos used the perches as perching site and devoured the larvae by taking short flights and picked them from the paddy field,” Dr Saikia said. He added that the dwindling practice of summer ploughing should also be encouraged, as it destroys the larvae hibernating on earth.

Dr Saikia also suggested that farmers should use the insecticides at recommended doses and not in excess. “Quinalphos is less toxic and it is advisable to recommend it more,” he added.

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