DAMPAK APLIKASI INSEKTISIDA PERMETRIN TERHADAP SERANGGA HAMA (THOSEA SP.) DAN SERANGGA PENYERBUK (ELAEIDOBIUS KAMERUNICUS) DALAM AGROEKOSISTEM KELAPA SAWIT

Abstract

Impact of Permethrin-Insecticide Application on Insect Pest (Thosea sp.) and Insect Pollinators (Elaeidobius kamerunicus) in Oil Palm Agroecosystem.  Insecticide efficacy studies are usually determined from the target insect (pest) data without regard to the effect of that treatment on the non-target insects (such as pollinators). This study examined  the effect of  permethrin  (one of widely used insecticides for agriculture)  on   defoliating insect pest (nettle caterpillar, Thosea sp.) and  insect pollinator (weevil, Elaeidobius kamerunicus) which lives on pollen of  male oil palm flowers.  A complete block design was used in which each of  four blocks consisted of 5 treatments (4 concentrations of permethrin; 50;  100; 200; and 250 ppm and control) .  The results clearly demonstrated  that the application of  permethrin reduced significantly the number of  nettle caterpillar  throughout all sprayed plants (up to 100% 14 d after treatments).  A significant difference in mean population of the caterpillar were detected between plots sprayed with permethrin (0.05; 0.25; 0.53; and 2.00 larvae/leaves at  concentrations of  250; 200; 100; and 50 ppm respectively) and control plant  (5.2 larvae/leaves) 3 d after treatments. This  insecticide effects  persisted for at least  14 d after treatments.  On the other hand,  permethrin application in oil palm agroecosystem had adverse effects on main pollinator (E. kamerunicus).  The number of weevil pollinators on sprayed plants (12.5; 59.3; 77.5; and 209.5 weevil/male flower at  concentrations of 50; 100; 200; and 250 ppm respectively) were significantly fewer compared to the control plants (976.0  weevil/male flower).  The results indicate that, despite high efficacy of permethrin in reducing number of insect pests  of oil palm (Thosea sp.), its application also cause a severe impact on  important insect pollinators  (E. kamerunicus).