ABSTRACT
The annual bluegrass weevil (ABW), Listronotus maculicollis (Kirby), a significant pest of short-mown turfgrass in eastern North America, has developed widespread insecticide resistance because of excessive synthetic insecticide use. The proper monitoring of this pest may reduce insecticide applications in time and space. This study evaluated three sampling methods (soap flushing, vacuuming, and mowing) in golf course greens and fairways for monitoring adult ABW. Soap flushing was the most efficient method, especially with an 0.8% solution in two portions of 500 mL, extracting over 75% of the adults, and the extraction efficiency was not affected by the temperature or time of day. Vacuuming was more effective for recovering adult ABWs on greens (4-29% extracted) than on fairways (2-4%) but was not affected by the time of day. The extraction of adult ABWs in mower clippings was significantly affected by mowing height (higher recovery from greens versus fairways), and the efficiency decreased with the temperature. Adding a brush to the mower increased adult removal (from 15% to 24%) in greens at higher temperatures (18-25 °C); 70% of adults recovered in the clippings were unharmed. Overall, our findings suggest that soap flushing should be the preferred method for monitoring adult ABWs, and vacuuming might be a viable alternative for greens.
ABSTRACT
The invasive spotted-wing drosophila, Drosophila suzukii (Matsumura), is a major pest of soft-skinned fruits. Since its introduction into North America and Europe, significant progress has been made in understanding the volatile cues used by this fly during food, oviposition site, and mate finding. Despite this progress, commercially available lures are non-selective. Here, we tested two Hanseniaspora uvarum (Niehaus) yeast compounds (isoamyl acetate and isobutyl acetate) and a leaf compound ß-cyclocitral alone and in combination with a blend of four fermentation compounds ('Fermentation lure': acetic acid, ethanol, methionol, and acetoin) to improve D. suzukii attraction and selectivity. In laboratory assays, males and females were attracted to all seven individual compounds, although in electrophysiological assays, their antennae exhibited a dose-dependent response to only four of these compounds. In two-choice cage studies, the Fermentation lure was more attractive to D. suzukii than water controls, whereas ß-cyclocitral and the mixture of isoamyl acetate and isobutyl acetate were not attractive in this larger-cage study. Moreover, adding the two-component H. uvarum compound blend to the Fermentation lure reduced D. suzukii attraction to the Fermentation blend. When these experiments were repeated in blueberry, raspberry, blackberry, and cherry orchards across several states in the United States over 2 yr, similar outcomes were observed: ß-cyclocitral or the mixture of the H. uvarum blend did not improve the attractiveness of the Fermentation lure or its selectivity. This study demonstrates that cues from different sources may interfere with each other and reduce D. suzukii attraction to otherwise attractive odor combinations.
