Laboratory and field susceptibility of blueberry spanworm (Lepidoptera: Geometridae) to conventional and reduced-risk insecticides

Blueberry spanworm (Itame argillacearia Packard) is a key insect defoliator of wild blueberry, an important crop in north-eastern North America. We evaluated the susceptibility of blueberry spanworm to several reduced-risk insecticides in laboratory and field experiments. Two populations from two Canadian provinces were studied in the laboratory. Both were highly susceptible to flubendiamide, spinetoram and deltamethrin, although there were inter-population differences, and flubendiamide was slower acting. Flubendiamide, spinosad, spinetoram, and methoxyfenozide demonstrated good suppression of economically damaging populations of blueberry spanworm larvae in the field.

► Reduced-risk insecticides were tested against blueberry spanworm. ► Toxicity of flubendiamide and spinetoram was determined for two populations. ► There was high but differing susceptibility; flubendiamide was slower acting. ► Flubendiamide, spinosad, spinetoram and methoxyfenozide gave good field control. ► Applications of Beauveria bassiana had no impact on spanworm numbers.