Effect of Some Natural Compounds on Aonidiella Aurantii (Maskell) (Hemiptera; Coccoidea: Diaspididae) and Its Parasitoid Comperiella Lemniscata Compere and Annecke (Hymenoptera: Encyrtidae) on Citrus in Egypt

Abstract

Aonidiella aurantii (Maskell) (Hemiptera; Coccoidea: Diaspididae) is a serious pest on various economic crops in Egypt. The main injury caused by this insect is the ingestion of plant sap. Severely infested plants grow poorly, may drop their leaves prematurely and can suffer dieback of twigs and branches. The encyrtid parasitoid, Comperiella lemniscata Compere and Annecke (Hymenoptera: Encyrtidae) has been recorded as an effective parasitoid of armored scale insects in various parts of the world, including Egypt. The present paper describes some laboratory and field tests on the effect of KZ oil, Neemex, Sulphur and Actalic compounds on A. aurantii and its parasitoid. In the laboratory tests, five concentrations of KZ oil, Neemex, Sulphur and Actalic were used; twenty infested leaves of citrus were dipped in each concentration for five seconds. Leaves were divided into five replicates. Five leaves were dipped in clean water as untreated controls. The cultures was maintained at room temperature about 25±1°C and 65±1% relative humidity. After 24 hours, the live A. aurantii and parasitoids were counted.. The results suggested that the potency of KZ oil, Neemex, Sulphur and Actalic varied greatly between compounds and concentrations. Also the results suggest that when adult female and nymphal A. aurantii and the adult parasitoid were treated with the these chemicals , the percentage mortality ranged from 74.0-95% with KZ oil, 45.0-89.4% with Neemex, 57.2-93.8% with Sulphur and 82.5-100% with Actalic respectively. In field tests, two fields were selected. The first had a heavy infestation of A. aurantii and the second had abundant parasitoids. The fields were treated twice, in 2008 and 2009, and samples were collected after 3, 7 and 15 days post-treatment. Neemex and Sulphur gave moderate effects against the nymphs and adult female of A. aurantii, with average mortalities of 60 & 57% due to Neemex and 64 & 61 % due to Sulphur after 15 days in the two years. The parasitised scales had percent mortalities of 55 & 59 % respectively after 15 days. On the other hand, Actalic gave high efficacy against all targets, with 95 & 96% and 95 & 98% mortalities after 15 days against A. aurantii in the 2 years, while the mortality of the parasitised scales was 84 & 81% after 15 days in the 2 years, respectively.EFFECT OF SOME NATURAL COMPOUNDS ON AONIDIELLA AURANTII (MASKELL)