Monitoring Eastern flower thrips and soybean thrips (Thysanoptera: Thripidae) and the generalist predator, insidious flower bug (Hemiptera: Anthocoridae) in the American Midwest Suction Trap Network

<p>Eastern flower thrips (<em>Frankliniella tritici</em>) and soybean thrips (<em>Neohydatothrips variabilis</em>) are vectors of soybean vein necrosis virus (SVNV) and have increased in importance since the detection of the SVNV in 2008 in Arkansas. Understanding the factors that influence the timing and extent of these insects’ activity, along with their predators such as the insidious flower bug (<em>Orius insidiosus</em>), could contribute to improved management. Here, we compiled monitoring data between 2020-2023 from the American Midwest Suction Trap Network and examined associations between the timing of early and late activity, cumulative activity density, weather, landscape composition, and host plant phenology. We found that the activity of Eastern flower thrips began earlier, and insidious flower bug activity occurred later when conditions were warmer. In contrast, the activity of soybean thrips began earlier when there was higher edge density in the landscape but was not coincident with the timing of soybean bloom, suggesting an important role for non-crop host plants in early activity of these insects. Despite becoming active later, soybean thrips had greater cumulative activity density where it was warmer, a discordance suggesting the importance of migration in their overall abundance. Suction trap captures might therefore reflect the influences of local conditions as well as migratory movements on soybean thrips activity. Soybean thrips and insidious flower bug cumulative activity densities were also found to be positively correlated, suggesting that insidious flower bugs may be opportunistically utilizing soybean thrips as prey. Continued regional monitoring of these insects could be used to improve vector management.</p>