Synergistic activity of sesame oil formulation with Quinalphos and three acaricides against tea looper, Hyposidra talaca Walker (Lepidoptera:Geometridae) and tea red spider mite

Abstract

The tea looper (Hyposidra talaca) and the red spider mite (Oligonychus coffeae) are two major pests of tea in northeastern India, leading to 15-20% crop loss annually. The present study was carried out to find out the synergistic activity of sesame oil formulation (SOF) with Quinalphos and three acaricides viz. Propargite 57EC, Fenpyroximate 5EC and Fenazaquin 10EC against these two major tea pests. The addition of sesame oil formulation reduced the LC50 value of Quinalphos to 855.38 ppm from 1114.36 ppm in Quinalphos alone, giving a synergistic ratio of 1.30 fold against the second instar H. talaca. The combination of sesame oil formulation and Quinalphos exhibited significant enhancement of antifeedant activity, compared to individual treatment against the third instar H. talaca. Against the red spider mite, the addition of SOF reduced the LC50 values of propargite 57EC, Fenpyroximate 5EC and Fenazaquin 10EC to 17.05, 17.22 and 12.38 ppm from 43.56, 44.92 and 27.01ppm respectively, giving synergistic ratio of 2.55, 2.60 and 2.18 fold. The results clearly indicated that the sesame oil formulation can enhance the bioactivity of Quinalphos and three acaricides viz. Propargite 57EC, Fepyroximate 5EC and Fenazaquin 10EC. Therefore the SOF could effectively be utilized as a natural synergist for the management of the tea looper and the red spider mite.