The direct and indirect toxicity of selected insecticides of coffee insect pests to the pollinator heterotrigona itama cockerell / Noor Albannia Natasya Jabi

Beverage-yielding plant of Coffee (Coffea spp.) is one of the cultivated industrial crops in Malaysia. This crop needs insect pollinators includes honeybee, stingless bee, and butterfly to produce much better quality and quantity of coffee bean. Heterotrigona itama Cockerell L. (Hymenoptera: Apidae) is a species of stingless bee that found abundantly in Malaysian forest and reported as one of main pollinators of the coffee plant. This species is actively reared for meliponiculture purposes, especially for its commercial-scale of honey production and among the greatest commercial potential as crop pollinators. The hive of H. itama can be placed amongst coffee plant which serves as pollinator as well as an additional income for the farmers. However, this species has been potentially exposed to agronomic practices, among which the use against pests of coffee. Insecticide toxicity to the beneficial insects was considered, as indirect toxicity due to the formulation of insecticide is purposely to manage insect pest. Subsequently, the stingless bee may enter in contact with these insecticides treatment in several ways; by direct contact (when the bee fly through toxic mist or dust during the insecticide application in the treated area) and indirect contact (when the bees walk on the post-insecticide contaminated plant surface). Bioassay toxicity test was conducted to the local stingless bee H. itama at Agricultural Research Station, Tenom. Four selected insecticides which commonly used to a managed coffee insect pest, namely deltamethrin, cypermethrin, malathion and chlorpyrifos. All insecticides were tested at five different concentrations against foragers of H. itama using topical and residual exposures. All experiments were replicated three times. The aims of this study were to assess the direct and indirect effects of recommended concentrations of four (4) selected insecticides on H. itama by using topical and residual bioassay techniques, and to obtain the lethal concentrations (LC) of each insecticide in the range of 50%, 75% and 95% kill. Lethal concentrations were obtained from probit analysis (SPSS 21) after 24-hour mortality post-treatment. The LC50 values for deltamethrin, cypermethrin, malathion and chlorpyrifos via topical exposure are 0.634ml, 0.333ml, 0.181ml and 0.123ml diluted in 500ml of water, meanwhile, the residual exposure LC50 values are 1.276ml, 0.328ml, 0.033ml, and 0.091ml in 500ml of water. This study proved that the toxic effect of insecticides is one of the factors affecting the reduction of the stingless bee population, it is advisable to limit the usage and distributions of insecticides chemical near the stingless bee colony and niche area