|Rang, Cecile - CIRAD|
|Frutos, Roger - CIRAD|
Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 20, 2000
Publication Date: June 20, 2001
Citation: Rang, C., Lacey, L.A., Frutos, R. 2001. The crystal proteins from Bacillus thuringiensis subsp. thompsoni display asynergistic activity against the codling moth, Cydia pomonella. Current Microbiology. 40:200-204. Interpretive Summary: Control of codling moth is traditionally accomplished using conventional chemical insecticides. Development of resistance to insecticides and concerns about their effects on humans and the environment will limit the availability of chemical insecticides in the near future. Alternatives to chemical insecticides include mating disruption and microbial insecticides. Non- chemical means of control will minimize insecticide contact with fruit and spare nontarget organisms including other insect natural enemies of codling moth. Our studies demonstrate the usefulness of a new class of toxin produced by Bacillus thuringiensis. Treatment of orchards with potent and selective microbial control agents such as the HNC toxin for control of neonate codling moth larvae has the potential to complement mating disruption control programs.
Technical Abstract: Crystal proteins from Bacillus thuringiensis subsp. thompsoni strain HnC are active against the codling moth, Cydia pomonella, a major pest of orchards. Inclusion bodies purified from strain HnC displayed an LC50 of 3.34 x 10-3 ug/ul. HnC purified crystals were 10-fold more active than Cry2Aa and Cry1Aa toxins and 100-fold more toxic than Cry1Ab. The 34-kDa and 40-kDa proteins contained in HnC inclusion bodies were shown to act synergistally. The toxicity of crystal proteins produced by the recombinant B. thuringiensis strain BT-OP expressing the full length native operon was about ten-fold higher than that of the 34-kDa protein. When the gene encoding the non-insecticidal 40- kDa protein, which is not active, was introduced into the recombinant strain producing only the 34-kDa protein, the toxicity was rained 10-fold and was similar to that of the strain BT-OP.