Identification and Screening of New Generation Insecticides against Cardamom Thrips ( Sciothrips cardamomi) in Cardamom Cultivations in Sri Lanka

Abstract

Two thrips species were identified from cardamom (Elettaria cardamomum) cultivations in Sri Lanka. They are the cardamom leaf thrips, Panchaetothrips indicus Bagnall (1912) and the cardamom thrips, Sciothrips cardamomi (Ramakrishna, 1935). Sciothrips cardamomi collected from Nuwara Eliya district is emerging as a devastating pest of cardamom (Elettaria cardamomum) in the district. Both adults and larvae damage panicles, flowers and capsules of cardamom. Injury to panicles leads to stunted growth, and damaged flowers fall prematurely. Affected tender capsules show scabby growth on the surface as they mature and hence have no market value. To manage this problem and as an immediate control measure, damage causing thrips were identified, damage estimated and seven new generation insecticides were screened at Kabragala Estate in Elamulla, Nuwara Eliya. The estimated direct pod damage was 91.7 ± 3.2%. Severely damaged pods showed significantly lower pod weight than undamaged pods. No significant difference in the pod weight was observed between undamaged pods and pods with less than 2/3 of scabby area. The insecticides Actara (thiamethoxam), Match (lufenuron), Regent (fipronil) and Calypso (thiacloprid) successfully reduced the pod damage while Matric (chromafenozide), Mimic (tebufenozide) and Mospilan (acetamiprid) did not reduce the damage percentage. But higher yields of 335.54 and 304.98 g/bush/harvest were obtained from the plots treated with Actara or Match respectively, in comparison to all other treatments. Therefore, either Actara or Match could be recommended for the management of S. cardamomi in cardamom plantations. Key words: Sciothrips cardamomi, Panchaetothrips indicus, Elettaria cardamomum doi: 10.4038/cjsbs.v37i2.501 Cey. J. Sci. (Bio. Sci.) 37 (2): 137-142, 2008