Empoasca decipiens Paoli (Hompotera: Cicadellidae) is a serious leafhopper pest of vegetables in greenhouses in southern Germany, UK and the Netherlands. At present no biological control techniques have been developed against E. decipiens. In the laboratory and greenhouse we studied the efficacy of the mymarid egg parasitoid Anagrus atomus (L.) and several entomopathogenic fungi. The fungal strains screened included two Metarhizium anisopliae strains (Ma43 and Ma57), and one strain of Beauveria bassiana (Bba113), Paecilomyces fumosoroseus (Pfr12) and Verticilium lecanii (Vl23). In screening experiments, all strains proved to be highly virulent to late L5 of E. decipiens, with highest mortality between 88-97% within seven days exposure at 1 x 107 conidia/ml. In dose-response experiments, mortalities significantly increased with rising dose rates and older nymphs (L3 and L5) were more susceptible than younger ones (L1). Spores collected from E. decipiens cadavers were able to successfully re-infect leafhoppers. The parasitoid A. atomus can be an important mortality factor in E. decipiens. Parasitoids are capable of successfully locating leafhopper eggs, hidden in tissue of various plant parts. Rates of parasitism exceeded 61%. The life cycle of A. atomus is considerably shorter than that of its host. In preliminary experiments on potential side effects of entomopathogenic fungi on A. atomus, all tested isolates had no influence on adult emergence and longevity, but rates of parasitism were significantly lower in the fungal treatments compared to the control. The latter might be due to either density effects or could indicate repellent features of the fungi on A. atomus.
Species 1: Homoptera Cicadellidae Empoasca decipiens (greenhouse leafhopper)
Species 2: Hymenoptera Mymaridae Anagrus atomus
Keywords: biological control
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