Side Effects of Spirotetramat and Imidacloprid on Hippodamia variegata Goezee Feeding on Agonoscena pistaciae Burckhardt & Lauterer

Abstract

The Adonis ladybird, <em>Hippodamia variegata</em>Goeze (Coleoptera: Coccinellidae) is known as an important predator of the Common pistachio psylla,<em> Agonoscena pistaciae</em> Burckhardt & Lauterer (Hemiptera: Psyllidae). Despite using the selective pesticides to manage the pests in the pistachio orchards, these chemicals have influenced non-target organisms like predators and parasitoids. In the present study, the effects of spirotetramat and imidacloprid (500 and 400 ml/1000 L, respectively) on some biological parameters of <em>H. variegata</em> fed on the common pistachio psyllawere investigated under laboratory conditions (27.5 ± 1°C, 65 ± 5% RH and 16:8 h L: D photoperiod). To this end, the eggs of ladybird beetles were exposed to pesticides via a Dipping method. In addition, the impact of pesticides on immature and adult stages was studied. The daily number of eggs laid by a female ladybird was also recorded in laboratory conditions. The results showed that spirotetramat and imidacloprid had increased the duration of immature developmental stages (egg, larva, and pupae) and the number of daily laid eggs of female ladybirds compared to those by control (Kolmogorov-Smirnov test, <em>p</em> <0.05). The highest and the lowest of net reproductive rates were also observed in control and imidacloprid treatments, respectively. Considering the results, the spirotetramat and imidacloprid had caused adverse effects on the demographic parameters of <em>H. variegata</em> and had also influenced the efficiency of this predator. Therefore, spirotetramat and imidacloprid were suggested to be used in IPM of <em>Agonoscena pistaciae</em> with caution.