LABORATORY EVALUATION OF PEST-MANAGEMENT STRATEGIES COMBINING ANTIFEEDANTS WITH INSECT GROWTH-REGULATOR INSECTICIDES

Two strategies have been evaluated for the integration of behaviour-controlling chemicals (semiochemicals) with highly selective but slow-acting pesticides in pest management regimens, using larvae of the mustard beetle, Phaedon cochleariae, and the diamondback moth, Plutella xylostella, as model insects. In the first method, plant extracts with antifeedant properties were applied to plant foliage together with the insect growth regulator pesticide, teflubenzuron; the extracts greatly restricted the amount of plant material that the insects consumed during the interval which occurred after they acquired a toxic dose but before the growth regulator took effect. In the second method, antifeedant and pesticide were applied to separate areas, i.e. antifeedant was sprayed on to the growing tips of young plants to drive insects down to the lower leaves, which are more tolerant of attack. The results showed that an antifeedant application to the upper leaves of the plant combined with a limited application of teflubenzuron to the lower leaves gave maximum protection of the plant foliage and maximum kill of insects coupled with minimum use of insecticide.