Effects of Adjuvants on the Efficacy of the Insecticide (Spinetoram 120 SC) Against Strepsicrates semicanellain EucalyptusPlantation

Spinetoram 120 SC is an insecticide used against the leafroller, Strepsicrates semicanella(Lepidoptera: Torticidae), in Eucalyptusplantations. Control efficacy in plantations is a difficult issue due in large part to weather. Adjuvants are added to reduce insecticide runoff from the leaf surface. Three adjuvants such as alkyl aryl polyglycol ether 400 g/L (Agristick), mixture of fatty alkyl sulphate and fatty alkyl betaine (CBA Stick 100), and condensate nonylphenolethylene oxide 95 g/L and polyvinyl alcohol 19 g/L (Indostick 100/20 SL) were tested with the insecticide spinetoram 120 SC against S. semicanella. Adjuvant treatments significantly increased the efficacy of spinetoram 120 SC in controlling S. semicanella. The CBA Stick with 3 and 2 ml L−1reduced S. semicanellaincidence best compared to the other treatments at 7 DAT (days after treatment) and 14 DAT. A rain simulation (10 mm) conducted at 30-min intervals after spraying was sufficient to show deterioration in insecticide efficacy. Spinetoram at a dosage of 0.5 ml L−1with the adjuvant CBA Stick at a dosage of 3 ml L−1was recorded as the best treatment for S. semicanellaat 14 DAT in a simulated rain of 10 mm.