The effects of kaolin particle film on Plutella xylostella behaviour and development

Studies were conducted to evaluate the effect of a kaolin-based particle film against the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). The effect of the particle film on development, survival and host plant selection was tested on calabrese seedlings, Brassica oleracea italica Plenck cv. Fiesta F(1), under controlled environmental conditions in the laboratory. Survival to adulthood was significantly reduced and development time increased on kaolin-treated compared with water-treated host plants. The hatch rate of neonate P. xylostella larvae from eggs laid on an artificial substrate was unaffected by the particle film applied after oviposition. Experiments showed that, when given the choice, significantly fewer larvae first made contact with the kaolin-treated compared with the water-treated plant material and that after 24 h there were still significantly fewer larvae present on kaolin-treated leaves. Adult females, however, deposited more eggs on host plants coated with the kaolin particle film. As part of this series of experiments the water control treatment was compared with plant material which had been sprayed with kaolin on the upper surface only and on both leaf surfaces. In general, any observed treatment effect was enhanced with an increase in the particle film coverage. The results warrant the extension of investigations of kaolin-based particle films to field-based P. xylostella management strategies.