Influence of host plant on the biocontrol of glasshouse mealybug.
The role of food plants in the biological control of Planococcus citri and Pseudococcus affinis was studied. The development of Planococcus citri and the parasitoid Anagyrus pseudococci was better on soyabeans than on Streptocarpus hybridus or Aeschynanthus ellipticus. Pseudococcids on plants of S. hybridus subjected to high water stress were smaller, less fecund and took longer to develop than those on unstressed plants. Few individuals of Leptomastix dactylopii were able to parasitize these mealybugs and the resulting parasitoids were small with longer development and shorter longevity. The searching behaviour of adults of the coccinellid Nephus reunioni was studied on 6 plants. The predator was most active on Citrus and least active on Passiflora. Cryptolaemus montrouzieri gave good control of Pseudococcus affinis on S. hybridus, Citrus, Passiflora, potato and coffee, while N. reunioni gave good control on Citrus but was less effective on S. hybridus. This paper was presented at an IOBC/WPRS Workshop on IPM in greenhouse ornamentals held in Cambridge, UK, on 8-11 September 1992.