Predation potential and prey-stage preference of two mirid bugs on different stages of Plutella xylostella.

The predation rate and prey-stage preference of two mirid predatory bugs Macrolophus pygmaeus Rambur and Nesidiocoris tenuis (Reuter) (Hemiptera Miridae), were investigated on the diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera Plutellidae), a noxious pest of cruciferous plants. In particular, predation capacity of each predatory stages of both predators was studied on the first, second and third larval instars of DBM. There were no significant differences in predation between the predators on eggs, second and third instar larvae of DBM. Among the different life stages of both predators, females had the highest predation on eggs and all larval instars of DBM. Preference indices for both mirid species indicated that there was a preference toward eggs, first instar and second instar larvae versus first instar, second instar and third instar larvae, respectively. The data of the current study suggest that M. pygmaeus and N. tenuis are effective predators of DBM particularly against eggs and first instar larva. It would therefore be worth to investigate how these mirids can be incorporated in biological control programs of DBM. [ABSTRACT FROM AUTHOR]