Friday, June 11, 2010


Suman Sahai

  • In China the mirid bug has begun to ravage plantations of apples, strawberries, pears, peaches and vegetables in the vicinity of Bt cotton fields. A once minor pest, the mirid bug has erupted as a major pest in the absence of pest control and now attacks fruit orchards and cotton fields after farmers reduced spraying insecticides on Bt cotton.

  • The State Bio-Control Laboratory of Assam has isolated two species of insect bio-agents and made it available to farmers for biological pest control. The two species of insects, Trichogramma japonicum and Trichogramma chillonis are found to be effective against borer pests like stem borer in brinjal, tomato, potato, as well as paddy, chilli and sugarcane, and farmers have already started accruing benefit from these bio-agents.

  • The major pest of brinjal, as also of tomato and chilli, all belonging to the Solanacaea family, is bacterial wilt, (caused by Ralstonia solanacearum), not shoot and fruit borer, which the Bt brinjal aims to target.

  • These findings along with data on the explosion of secondary pests of cotton in Bt cotton fields in China and elsewhere, shows how controlling one pest can trigger the spread of others.

  • The Bt approach to pest control is emerging as expensive, perhaps irrelevant, short lived and ineffective as a strategy for pest control.

  • Given the dynamic nature of host –pathogen relationships and the large pest density and pest profile in the tropics, the only possible solution is Integrated Pest Management.

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