Impact of hemp seed formulations on darkling beetles ( Tenebrio molitor) their reproduction and susceptibility to insecticides.

摘要

Darkling beetles and their larvae (Tenebrio molitor) are common pests in agriculture and are often treated with insecticides such as chlorpyrifos that is toxic to many nontarget organisms including humans. The hemp seed of Cannabis sativa is thought to influence insect development due to plant sterols that disrupt the physiology of the insect. A patent pending formulation consisting of hemp seed was developed as a potential pesticide from the research conducted in this thesis. The objective of the current research is to determine the impact that a developed hemp seed formulation has on the darkling beetles and their progeny. Mating success was measured by percentage of mates producing larvae. In addition, the study also tested this insect's susceptibility to chlorpyrifos following exposure to hemp seed treatments. Larvae were raised on three different treatments: wheat flour (control), 100% hemp seed flour, and a patent pending formulation called CannamixRTM Two types of bioassays were performed (dip and feeding assays) and mortality subsequently determined. For the dip assay, larvae were dipped into 0.00 and 0.02mg/ml chlorpyrifos solution for 30 seconds. For the feeding assays, beetles were fed chlorpyrifos treated flour at 0.0mg/kg, 0.5, 0.05, 5.0 and 50mg/kg concentrations. After exposing the insects to chlorpyrifos, mortality and acetylcholinesterase (AChE) activity were determined. Findings indicate that hemp seed formulations increased insect mortality and inhibited AChE activity even without the added toxicity of chlorpyrifos. Hemp seed has the potential to act as a natural organic insecticide that controls insect pests like darkling beetles and remains relatively low in toxicity.