Amitus fuscipennis, an alternative to the biological control of Trialeurodes vaporariorum by Encarsia formosa?

Abstract

Biological control of Trialeurodes vaporariorum (Homoptera Aleyrodidae) by Amitus fuscipennis (Hymenoptera Platygastridae) with or without Encarsia formosa (Hymenoptera Aphelinidae) was tested in both a glasshouse and a plastic greenhouse during two consecutive production cycles of a beef tomato crop on the Bogotá Plateau in Colombia. The mean temperature was around 16 °C in the plastic greenhouse and around 17 °C in the glasshouse. A. fuscipennis was introduced at a rate of 5 pupae per m2 per week during the first 13 weeks of the first cycle. During the second cycle, 2.5 pupae of both E. formosa and A. fuscipennis per m2 per week were introduced during the first 13 weeks. During the first cycle, control was obtained for 5 months in the plastic greenhouse and 3 months in the glasshouse, after which the population of T. vaporariorum adults increased to a maximum of 50 adults per plant. Parasitism was initially higher than 80% but then decreased to 56% in the plastic greenhouse and to 20% in the glasshouse. During the second cycle, biological control was successful in both greenhouses. Populations of T. vaporariorum were lower than 1.2 adults per plant and parasitism, caused mainly by E. formosa, was near 90% most of the time. Therefore, E. formosa is recommended to keep populations of T. vaporariorum at low levels in unheated greenhouses on the Bogotá Plateau. When high populations of T. vaporariorum are to be expected or control of high-density spots is required, A. fuscipennis could be a beneficial addition to E. formosa