Impact Of Natural Enemies To Leaf Eating Caterpillar Population On Oil Palm In North Sumatra Indonesia

Setothosea asigna is most important pest of oil palm especially in North Sumatera Indonesia. The caterpillar could reduce oil palm yield up to 90 and the infestation can spread in huge hectares in years. However there are a lot of natural enemies have recorded and most of them could controlled the outbreak of S. asigna effectively. Nectar pollen and water are the main food of parasitoids and predators. These foods are produced by flowering plants such as Antigonon leptopus Turnera subulata and Agreratum conizoides which are practiced in maintaining in oil palm plantations. Two families of predators Pentatomidae and Mantidae then 3 families of parasitoids are visit on these flowering plants in this study site. This study was to determine the impact of the natural enemies to S. asigna population. The results indicated that the Blocks are planted the flowering plants A. leptopus and T. subulata clearly could suppress the population of S. asigna under Economic threshold for 25 months. While the block which has the flowering plant A. conyzoides only three times outbreak of S. asigna was happened in March November and December 2015 and continued in February and March 2016. To keeping abundance of natural enemies in oil palm plantations should be encouraged of flowering plants which provided the source of foods of the natural enemies. It should be included for sustainable Integrated Pest Management.