Susceptibility of Nilaparvata lugens (Stal.) to a botanical insecticide formulation of Neem (Azadirachta indica A. Juss) and Citronella Oil (Cymbopogon nardus L. Rendle) mixture

Nilaparvata lugens (Stal.) is one of the main insect pests of rice plant in Indonesia. The farmer usually using synthetic insecticide to control this pest insect. However, unwise of using insecticides cause many negative impact such as resistance, resurgence, environmental contamination, and healthy problem. These were encouraged to search and development of natural resources origin from plant for insect pest control. Neem (Azadirachta indica) and citronella (Cymbopogon nardus) have insecticidal activity and safety for the environment. This study aimed to compare the susceptibility of N. lugens from Cipunagara (field population) and Banyuwangi (standard population) to the insecticide formulation made from neem and citronella oil mixture (50:15). The experiments used leaf-stem dipping and root dipping methods. N. lugens instar 4th were exposed to the treated rice plant for two days and after that they were provided with rice plants without treatment until ten days. The results showed that the LC50 value in the root dipping method was lower than that in the leaf-stem dipping method. In this test, the toxicity of neem and citronella oil mixture formulation was higher in the root dipping method and was effective in controlling N. lugens in both populations with the LC95 values were 2.09%-2.30%. The Resistance Ratio (RR) of N. lugens from Cipunagara population and from Banyuwangi population were < 1 in both leaf-stem dipping and root dipping tests, respectively. Therefore, N. lugens from Cipunagara population is still susceptable to neem and citronella oil mixture formulation.