Predation Rates of Macrolophus pygmaeus (Hemiptera: Miridae) on Different Densities of Eggs and Nymphal Instars of the Greenhouse Whitefly Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

Among the major predators of whiteflies in greenhouse vegetable crops, the predator Macrolophus pygmaeus (Rambur 1839) is included. The aim of the current study was to quantify the predation rates of M. pygmaeus on the eggs and on 2 nd , 3 rd and 4 th nymphal instars of the greenhouse whitefly Trialeurodes vaporariorum (Westwood). To accomplish this, the predation rate of unstarved 5 th instar nymphs of M pygmaeus was recorded in Petri dishes at 25 ± 1 °C, 65 ± 5% rh and 16L: 8D photoperiod. In each Petri dish a leaflet of tomato with the respective prey was placed. The prey densities used were: i) 30, 60, 90, 120 and 150 eggs; ii) 20, 40, 60 and 80 nymphs of the 2 nd instar; iii) 10, 20, 30 and 40 nymphs of the 3 rd instar and iv) 5, 10, 15 and 20 nymphs of the 4 th instar of the whitefly. The results showed that the predation rates increased with prey density. However, significant differences were not recorded between the predation rates found at the two highest densities for the eggs, the 3 rd and the 4 th instar nymphs. The highest mean daily consumption was 94 eggs, and 56.5, 24.4 and 11.8 nymphs of the 2 nd , 3 rd and 4 th nymphal instar, respectively. These results indicate a high potential of M. pygmaeus as a biological control agent of the greenhouse whitefly. Furthermore, this knowledge can be useful for the most appropriate implementation of whitefly biological control strategies with the aid of this predator.