Fumigant and contact effects of tea tree oil (Melaleuca alternifolia L.) formulations on Sitophilus oryzae L. (Col.: Curculionidae)

Extensive use of insecticides negatively affects the environment and human health. Essential oils are thought to have less toxic effects on humans, the environment and non-target insects. In this study, the contact and fumigant effects of tea tree oil (Melaleuca alternifolia) belonging to the Myrtaceae family and its formulations (TTO, F14, F15, F16, F17, F18) were tetsed on Sitophilus oryzae adults under laboratory conditions. The F15 formulation showed the gretaets toxicity in both contact and fumigant toxicity biotestes as the least toxicity was observed in the TTO formulation for the contact effect and the F14 formulation for the fumigant application. The LD10, LD50 and LD90 were calculated as 1.13, 6.69, 39.40 µl/insect for the contact effect dose-respoce bioassay with F1, respectively, while fumigant effect LC10, LC50, LC90 were calculated as 0.42, 1.87, 8.30 ml/L, respectively. In contact toxicity bioassay, the LT10 was calculated as 4.33 hours while the LT50 and LT90 were 12.18 and 34.27 hours, respectively. The LT10 was 9.85 hours as LT50 and LT90 were s 25.51 and 66.05 hours for fumigant toxicity bioassay, respectively. As a result of the study, it was determined that the essential oil of tea tree oil, especially the F15 formulation, has the potential to manage the rice weevil poplation.