Spirotetramat is toxic to leafrollers on kiwifruit

Abstract

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