FUNGAL BIOCONTROL OF THE DIAMONDBACK MOTH

Authors: Vandenberg, John; PELL, J - IACR-ROTHAMSTED

Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2001
Publication Date: 9/1/2001
Citation: VANDENBERG, J.D., PELL, J.K. FUNGAL BIOCONTROL OF THE DIAMONDBACK MOTH. SOCIETY FOR INVERTEBRATE PATHOLOGY ANNUAL MEETING. 2001.

Interpretive Summary:

Technical Abstract: The diamondback moth, Plutella xylostella, is a worldwide pest of crucifers and can be devastating in tropical countries. Resistance to insecticides, including those based on Bt, has lent urgency to finding alternatives. We have employed inoculative and inundative strategies, both of which may be appropriate for use in tropical environments. We have focused on Zoophthora radicans and Beauveria bassiana. Employing an autodisseminatio strategy, Pell and others attracted male P. xylostella with a sex pheromone to an autoinoculation station. In this way, less fungus and pheromone are required than if either was used alone. The strategy relies on fungal establishment and development of a population-regulating epizootic. Using a mycoinsecticidal approach, Vandenberg and others showed that P. xylostella larvae were effectively controlled by B. bassiana applications to cabbage seedlings grown in a nursery. Because of the partial overhead protection in nurseries, fungal spores remained viable for an extended period. In open-field trials, combinations of B. bassiana and Bt were used to manage three lepidopteran pests. P. xylostella was effectively managed using B. bassiana in this way, but the fungus alone did not provide adequate control of the other pests. Early-season applications of B. bassiana with later applications of Bt kept larval populations low while preserving the marketability of cabbage heads. This approach reduces the number of applications of Bt and therefore reduces the likelihood of resistance developing to it.