The cabbage whitefly Aleyrodes proletella and its natural enemies on wild cabbage Brassica oleracea on the Kent coast

Abstract

Field surveys of Aleyrodes proletella populations on wild cabbage Brassica oleracea on the Kent coast were carried out in 2009 and 2010 in order to investigate the ecology of the whitefly in this habitat, to identify native natural enemies and to quantify their impact. Whiteflies were found to overwinter largely as adults on the most sheltered plants in a location and, while dispersal to other plants was evident, reached the greatest numbers on these plants. Three putative generations of juvenile whiteflies were monitored throughout 2010. It was found that more frequent monitoring would be necessary to estimate survival to eclosion; this, along with the loss of puparial exuviae from wild cabbage leaves under field conditions prevented conclusive estimates of survival to be calculated. Observations of potential predators and estimates of parasitism were possible; observed parasitism peaked in the second generation at 2.75% of all juveniles monitored. Limited sampling identified several chalcid parasitoid wasp species (Encarsia tricolor, Encarsia inaron and Euderomphale chelidonii) and a coccinellid beetle, Clitostethus arcuatus, as antagonists