A Lethal Cocktail for the Chickpea Podborer
Dead crushed larvae of the podborer pest,
well mixed with water and a stabilizer, yield a lethal cocktail
used by Indian farmers to spray their chickpea fields.
A forty percent increase in chickpea yield
was achieved by a group of farmers developing this new biological
pesticide in collaboration with the International Crops Research
Institute for the Semi-Arid Tropics (ICRISAT)
based near Hyderabad.
The podborer, the caterpillar of the insect
Helicoverpa Armigera, used to destroy over half the earlier harvests
of chickpea, the most important post-monsoon crop in the Medak
district of Andhra Pradesh.
The farmers contacted ICRISAT, a center
supported by the Consultative Group on International Agricultural
Research (CGIAR), through the Deccan Development Society, a local
non-governmental organization. Ten on-farm trials of alternative
podborer control methods were conducted by farmers in Kappadu
village, together with ICRISAT scientists.
The trials involved a conventional chemical
insecticide, a botanical insecticide derived from the domestic
neem tree, and the nuclear polyhedrosis virus (NPV), a natural
enemy of the podborer. The NPV particles are ingested by larvae
as they voraciously feed on the sprayed chickpea leaves.
The dying larvae are full of brown liquid
which contains the virus particles and are collected for the cocktail
which should be sprayed at sunset because the virus is inactivated
Vitthal R. Bhagwat is leading a team of
ICRISAT entomologists that developed an integrated pest management
package consisting of an improved chickpea variety, the botanical
insecticide, and the NPV cocktail.
"On-farm experiments have clearly shown
the efficacy of this approach," says Bhagwat of the new,
eco-friendly and low-cost technology readily adopted by the farmers
who had been trained to monitor pheromone traps, count the larval
population per plant, and determine the right stage to apply the
NPV. They learned how to mix the cocktail and decided to apply
three sprays at weekly intervals.
"We did not believe when we were told
about it but now we can count on this cheap and effective package,"
says one of the Kappadu farmers, Narasa Reddy. "We observed
that friendly birds only visit plots that were
not sprayed with chemical or botanical insecticide, but they are
intensely active on the plots sprayed with NPV where they feed
on dead larvae that they can easily pick off the
Bhagwat says ICRISAT will continue the on-farm
research in the next season. More farmers need to be trained to
prepare and use their own sprays as part of a user-friendly and
environmentally benign technology.
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)