Lethal effects of spirotetramate on Oenopia conglobata contaminata Menetries (Col.: Coccinellidae) under laboratory conditions

عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
The common pistachio psylid, Agonoscena pistaciae Burckardt and Lauterer (Hem.: Aphalaridae), is a key pest in pistachio orchards. Recently, spirotetramate pesticide is used to control A. pistaciae. The low side-effect of pesticide on biocontrol agents is important in success of IPM programs. Therefore, in this study, lethal effects of spirotetramate (field recommended dose) were investigated on egg, first and third instar larvae and adults of Oenopia conglobata contaminata Menetries (Col.: Coccinellidae), as the most important predator of A. pistaciae in pistachio orchards. The trials were conducted under laboratory conditions (27. 5 ºC, 65 ± 5% R. H. and 16:8 (L: D) photoperiod). The bioassay were carried out using two kinds of meals, 1) the feeding on common pistachio psyllid nymphs and 2) the feeding on eggs of Ephestia kuehniella (Zell.). The ladybird eggs were treated by dipping method. Three bioassay methods were used on larvae and adults stages, including residual contact, topical application and sprayed preys methods. The effect of spirotetramate on this ladybird was estimated based on IOBC method. The results showed that the susceptibility of larvae and adults were the most in residual contact method and after that, feeding on sprayed preys and topical application methods. The highest susceptibility was recorded in adults (effect percentage < 40%) of O. conglobata contaminata in residual contact method. Also, the highest effect percentage of spirotetramate on egg, first and third instar larvae were recorded, 24.88, 17.05 and 15.33% respectively. The ladybirds reared on eggs of E. kuehniella were showed more susceptibility to spirotetramate. The spirotetramate was harmless on egg, first and third instar larvae of this ladybird (in all methods and two kinds of meals). While, its effect on adults only in residual contact method was slightly harmful. Therefore, the result proved compatibility of spirotetramate with biological control.
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