Lepidopteran HMG-CoA reductase is a potential selective target for pest control

As a consequence of the negative impacts on the environment of some insecticides, discovery of eco-friendly insecticides and target has received global attention in recent years. Sequence alignment and structural comparison of the rate-limiting enzyme HMG-CoA reductase (HMGR) revealed differences between lepidopteran pests and other organisms, which suggested insect HMGR could be a selective insecticide target candidate. Inhibition of JH biosynthesis in vitro confirmed that HMGR inhibitors showed a potent lethal effect on the lepidopteran pest Manduca sexta, whereas there was little effect on JH biosynthesis in Apis mellifera and Diploptera punctata. The pest control application of these inhibitors demonstrated that they can be insecticide candidates with potent ovicidal activity, larvicidal activity and insect growth regulatory effects. The present study has validated that Lepidopteran HMGR can be a potent selective insecticide target, and the HMGR inhibitors (especially type II statins) could be selective insecticide candidates and lead compounds. Furthermore, we demonstrated that sequence alignment, homology modeling and structural comparison may be useful for determining potential enzymes or receptors which can be eco-friendly pesticide targets.

Spirotetramat is toxic to leafrollers on kiwifruit

Spirotetramat is an ambimobile selective insecticide used widely in the horticulture industry for controlling a broad range of sucking pests in perennial and annual crops It has become the standard chemical for the control of armoured scale insects in kiwifruit During an experiment to test the effects of spirotetramat (formulated as Movento 100SC) on phytohormone levels it unexpectedly caused high levels of mortality to neonate brownheaded leafroller (Ctenopseustis obliquana) larvae (96 of treated plants with dead larvae compared with 9 in unsprayed controls) exposed one day after spraying to runoff on small potted A deliciosa Hayward plants Repeating the experiment with different plants and third instar larvae resulted in 98 treatment mortality compared with 29 on untreated controls A third experiment using neonate larvae applied to the same plants as the second experiment 10 days after the spray application resulted in 76 treatment mortality compared with 20 on control plants Spirotetramat can only be used preflowering and leafroller control sprays are applied principally during the first 6 weeks after fruit set However the potential contribution of spirotetramat to leafroller control on kiwifruit should be investigated further