2024 Volume 49 Issue 4 Pages 285-291
The insecticide susceptibility of Helopeltis theivora Waterhouse (Hemiptera: Miridae) is being evaluated using shoot and glass-vial assay as described by IRAC. However, the reliability of the assay depends on feeding preference and contact toxicity. Hence, the cocoa pod was used as a substrate to test the susceptibility of H. theivora in comparison with existing methods. The experimental results revealed that the LC50 value of all of the insecticides was relatively lower in the pod bioassay than the other two methods and exhibited maximum mortality within 6 hr of post-exposure. Among insecticides, fipronil was the most effective molecule followed by lambda-cyhalothrin. H. theivora, which prefers to feed on a pod due to more tissue turgidity, thus facilitated adequate sap ingestion; whereas, these were limited in shoot and glass-vial bioassays. Therefore, it could be used as a methodology to determine the susceptibility of H. theivora against a wide range of insecticide molecules.
