Effects of spirotetramat with different additives on the common pistachio psyllid, Agonoscena Pistaciae (Order: Family) and parasitoid wasp, Psyllaephagus Pistaciae (Hym., Encyrtidae)

Abstract

Background and Objectives Detergents and soaps can be used as co-adjuvants (in the tank) for conventional or biological pesticides. Detergents and soaps can also be applied first to debilitate pest insects and mites, and later along with spraying insecticides and miticides. In both cases, a rate reduction occurs for conventional and more expensive and restricted products. The spirotetramat as an insecticide is used to control the sucking insect pests. Surfactants are used for increasing the insecticide's effect. Water pH is one of the most important factors influencing efficiency of insecticides against the common pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Aphalaridae), as the most important pest found in Iran's pistachio orchards. Therefore, this study was conducted to investigate the effect of Jonobegan spraying soap, pH-reducing Citral soap ,and Thymol soap on the spirotetramat's efficiency in pistachio orchards and its effects on the parasitoid wasp, Psyllaephagus pistaciae (Hymenoptera: Encyrtidae). Materials and Methods In this study, the effect of insecticides including spirotetramat (Monvento® SC 100), Jonobegan spraying soap, and spirotetramat mixture (Jonobegan, Thymol® soap, and pH-reducing Citral® soap) was investigated on reduction of population density of nymphs of the common pistachio psyllid under field conditions. Experiment was carried out as randomized complete block design with four replications and six treatments. Sampling was done one day before and 3, 7, 14, and 21 days after application of the treatments. Efficiency percentage of treatments on A. pistaciae was calculated by Henderson-Tilton formula. Means were compared by Tukey's test at P = 0.5%. Results The results showed a highly significant difference between the treatments including Jonobegan spraying soap, spirotetramat, spirotetramat + Thymolsoap, spirotetramat + Jonobegan spraying soap, and spirotetramat + pH-reducing Citral soap against A. pistaciae. According to the international organization for biological control (IOBC) indices, all the treatments were harmless for parasitoid wasp, p . pistaciae. Discussion Two days after application of the treatments, a significant difference was observed in the spirotetramat plus additives of Thymol soap, and pH-reducing Citral soap compared to spirotetramat alone. Because, the spirotetramat has a delaying effect, on 7, 14, and 21 days after application of the treatments, there was no significant difference between spirotetramat and spirotetramat plus additives in terms of reducing population density of the nymphs of A. pistaciae. The results showed that additives of Jonobegan spraying soap , Thymol soap ,and pH-reducing pH Citral soap could not increase the effect of spirotetramat significantly on 7, 14 ,and 21 days after application of the treatments. On 7 and 14 days after the intervention, the effect of spirotetramat in combination with pH-reducing Citral soap was significantly more than spirotetramat combined with Thymol soap and Jonobegan spraying soap. Also, it should be mentioned that all the treatments were harmless for parasitoid wasp, p . pistaciae.