Repellent Ability of Encapsulated Guava Leaves Extract and Horticultural Mineral Oil (HMO) on the Feeding Behaviour of Diaphorina citri

Abstract

Repellency is one of strategies to reduce Diaphorina citri attack. Guava leaf extract (GLE) and horticultural mineral oil (HMO) are well-known as repellents against D. citri but have short persistence. This research was conducted to increase the persistence of GLE and HMO extracts by using simultaneous co-delivery as part of environmentally friendly control of D. citri. The treatments used were 5% GLE, 5% HMO, 5% GLE + 5% HMO, 5% encapsulated GLE, 5% encapsulated HMO, 5% encapsulated GLE + 5% encapsulated HMO, and aquadest as control. The result shows that 5% HMO, 5% GLE + 5% HMO, and 5% encapsulated GLE have a repellency effect on D. citri. In the non-encapsulated treatments, the percentage of D. citri stayed at treated citrus leaves increased significantly at 9 and 12 hours after application except 5% GLE + 5% HMO. Exposure to 5% GLE, 5% HMO, and 5% encapsulated GLE. The most dominant of GLE compounds was lactose and d-Glycero-l-gluco-heptose. The most dominant of HMO compounds were 17-Pentatriacontene, Tetrapentacontane 1,54-dibromo- and tert-Hexadecanethiol. Encapsulation of 5% GLE can increase the persistence of GLE as a repellent compound for D. citri, but this effect does not occur in HMOs.