Establishing the behavioral basis for an attract-and-kill strategy to manage the invasive Halyomorpha halys in apple orchards

Abstract

Halyomorpha halys (Stal), the brown marmorated stink bug, is an invasive, polyphagous insect that causes serious economic injury in particular to specialty crops in the United States. Growers have been forced to respond by increasing the frequency of broad-spectrum insecticide (e.g., neonicotinoid, pyrethroid, and carbamate) applications. One strategy to reduce reliance on insecticides is known as "attract-and-kill'' whereby the targeted insect is attracted to a spatially precise location to be eliminated by a killing agent such as an insecticide. This approach can substantially reduce the amount of insecticide used by sparing alternate row middle or whole block sprays. For apple orchards, we propose baiting select border row trees with the H. halys aggregation pheromone and synergist and subsequently treating these baited trees with effective insecticides to kill H. halys throughout the growing season. To evaluate the behavioral basis of this approach, we conducted orchard trials with black pyramid traps, harmonic radar, and trials using baited apple trees sprayed weekly to quantify H. halys arrestment area, retention time, adult and nymph annihilation, and fruit injury in and near these attract-and-kill sites. The arrestment area for H. halys was confined to a 2.5 m radius around the pheromone-and pheromone synergist-baited trap regardless of pheromone dose (84 or 840 mg), while the retention capacity of adults was significantly increased by pairing the aggregation pheromone and synergist with a fruiting host plant compared with non-host sites. Damage to fruit harvested from baited attract-and-kill trees was high, but minimal in surrounding unbaited neighboring apple trees. Our results suggest attract-and-kill may be an effective strategy for managing H. halys season-long.