Pink bollworm is considered a dreaded pest of transgenic cotton, the infestation of which ranges from 30-90% of the cropping area, at times impacting yield to the extent of 90%.
The new-generation insecticides have become redundant due to the cryptic nature of the insect, which spends the majority of its lifecycle in the closed boll. The damage to the crop can only be recognised at the time of the boll opening when it is too late.
Japanese technology
Given this background, the new technology of using PB Knot rope to cause mating disruption’ is adopted in demonstration fields in Gujarat and Maharashtra, which comes as a new ray of hope for cotton farmers. The technology, originally developed in Japan by Shin Etsu, a chemical company, is imported by Pesticide India Limited.
In Andhra Pradesh, this project has been implemented this year in an extent of 50 acres of cotton field in Julakallu village of Kurnool district, involving thirty small and marginal farmers.
PB Knot rope
A PB Knot rope is essentially a 30 cm plastic vinyl rope which releases female sex pheromones of the insect in large doses. The rope is tagged at the rate of 160 knots per acre over the 50 acres.
“The key to the success of this technology lies in the timing of the tagging, which should be done 35-40 days after sowing and implemented on a community basis in an extent of at least 50 acres”N.C. VenkateswarluAssociate Director of Research, RARS
“Generally, the female pink bollworm releases 3 mg of sex pheromone whereas each PB Knot releases around 158-160 mg. The high dosage confuses the male moth in locating the actual female, and its futile search for the female partner eventually results in the death of the male adult, thus hampering the mating process,” explains M. Sivaramakrishna, scientist at RARS (Regional Agricultural Research Station), who is in charge of the project.
“The key to the success of this technology lies in the timing of the tagging, which should be done 35-40 days after sowing and implemented on a community basis in an extent of at least 50 acres,” says N.C. Venkateswarlu, Associate Director of Research, RARS. The scientific fraternity believes this technology would become a game-changer in protecting the interests of cotton farmers.
