The parasit-host relationship between Encarsia formosa Gahan (Hymenoptera, Aphelinidae) and Trialeurodes vaporariorum (Westwood) (Homoptera, Aleyrodidae). 24. Effectiveness of Encarsia formosa in the greenhouse at low temperature
1987
Hulspas-Jordaan, P.M. (Leiden Univ. (Netherlands). Dept. of Population Biology. Zoological Lab.) | Christochowitz, E.E. | Woets, J. | Lenteren, J.C. van
It has been suggested that the intended lowering of glasshouse temperatures might make biological control of Trialeurodes vaporariorum with Encarsia formosa impossible. Based on new data we expected that there would be not such a problem. This paper describes a glasshouse experiment to test our expectation, with a tomato crop and a temperature regime of 18 degrees C by day and 7 degrees C at night. The experiment lasted 18 weeks. From the sixth weeks onwards the E. formosa population developed faster than the whitefly population1159 and the parasitization percentages were very high (between 60 and 86 per cent). The whitefly population decreased considerably in numbers in week 13, which is as soon as could be expected. E. formosa turned out to migrate well at the low temperature regime. A comparison with the results of a successful biological control experiment at 'normal' temperatures in a large commercial glasshouse confirmed our conclusion that successful biological control of T. vaporariorum with E. formosa is possible at low temperatures,
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