| heal.abstract |
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 2nd, 3rd and 4th nymphal instars of the greenhouse whitefly Trialeurodes vaporariorum (Westwood). To accomplish this, the predation rate of unstarved 5th 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 2nd instar; iii) 10, 20, 30 and 40 nymphs of the 3rd instar and iv) 5, 10, 15 and 20 nymphs of the 4th 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 3rd and the 4th instar nymphs. The highest mean daily consumption was 94 eggs, and 56.5, 24.4 and 11.8 nymphs of the 2 nd, 3rd and 4th 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. © 2009 E. Schweizerbart'sche Verlagsbuchhandlung,. |
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