THE IMPACT OF Elaeidobius kamerunicus FAUST POPULATION DENSITY AND SEX RATIO ON OIL PALM FRUIT SET IN INDONESIA

The persistent issue of low fruit set has remained a significant challenge in oil palm plantations in Indonesia for over 1.5 decades.One of the major causes of low fruit set is imperfect pollination due to Elaeidobius kamerunicus being the main oil palm pollinator.This study, conducted in Central Kalimantan, examined the role of weevils in pollinating nine fruiting positions within bunches of DxP Simalungun.The fruiting positions included the tip, middle and base spikelet, for each fruit location in the spikelet, the outside, middle and inside were considered.The artificial pollination test used 60 and 120 individual weevils/inflorescence, with the sex ratio of weevils including each of only male weevils, only female weevils and male/female weevil ratios of 1:2 and 1:4.Each treatment was trailed on 20 bunches, with approximately 1,100 fruits in each bunch.The results showed that male weevil treatment produced better fruit set only on the tip and outer sides.On the other hand, with female weevils, the fruit set of the spikelet at the base and the inner fruit was still relatively high.This was likely attributed to the smaller body size of female weevils, which enhanced their mobility and penetration into the inner parts of the spikelet.