Influence of Temperature and Light on the Feeding-Rate of Macrolophus pygmaeus (Rambur, 1839) (Heteroptera: Miridae) to Different Whitefly Species

Whiteflies are one of the major pests in greenhouse cultivation. Traditional methods of pest control involve the use of pesticides, which may lead to the emergence of resistive vermin. Therefore and in the context of growing health- and environmental awareness alternative ways of pest control should be considered. One alternative approach is the deployment of natural antagonists to the vermin. An effective use of those organisms within pest control requires studies on their biology, their behaviour and their climatic tolerance. Biology and behaviour of the studied insects are presented in a synopsis of the scientific literature. For this paper laboratory experiments on the predation rate of the beneficial organism M. pygmaeus were conducted on different whitefly species under various conditions of both, temperature and light. The treatment was carried out on eggs and larval stages of the whitefly species T. vaporariorum and B. tabaci with a photoperiod of 9 and 16 h light and under temperatures of 11-22A degrees C. On infestation by T. vaporariorum a high effectiveness (68,4-79,7%) of M. pygmaeus is shown under all tested light- and temperature conditions. On infestation of B. tabaci the effectiveness of M. pygmaeus was lower (8,5-46,1%). For unknown reasons those two species did not reproduce in the rearing. The high predation rate of M. pygmaeus on eggs and larval stages of T. vaporariorum proved that M. pygmaeus can be effectively deployed at low (11-13A degrees C) and intermediate (18-22A degrees C) temperatures under both, short day- and long day conditions. Especially at low temperatures and short day conditions M. pygmaeus so far turns out to be a useful supplement or alternative.