D3261: Kudzu bug (Megacopta cribraria) and associated egg parasitoids emergence rates in Alabama are predicted by weather indices

The kudzu bug, Megacopta cribraria (F.) (Heteroptera: Plataspidae), is a major economic pest of soybean in the southeastern United States. With climate warming, this pest is expected to move northward and cause additional crop damage. Parasitoid biocontrol is a potential method of integrated pest management for kudzu bug. Two species of egg parasitoid wasps have been observed emerging from kudzu bug egg masses in the southeastern United States: Paratelenomus saccharalis (Dodd) (Hymentoptera: Platygastridae) and Ooencyrtus nezarae (Ishii) (Hymenoptera: Encyrtidae). This paper uses egg mass emergence data collected between 2018-2020 in Alabama soybean fields and compares the data to weather indices. Indices included the number of days with minimum temperatures below zero, accumulated rainfall (mm m^-2), as well as species specific metrics of accumulated growing degree days, accumulated daily minimum temperature (^oC), and accumulated daily maximum temperature (^oC). Emergence of the generalist parasitoid, Ooencyrtus nezarae, was highly correlated with kudzu bug nymph abundance, accumulated degree day, accumulated daily temperatures, and precipitation. Ooencyrtus nezarae emergence was predicted in a stepwise regression equation by aggregated degree day and date of collection, which indicates that seasonality may be a predictor of its presence. In contrast, collections of the specialist parasitoid, Paratelenomus saccharalis, were near-zero throughout the collection period suggesting that this species may not be an effective biocontrol agent in the southeastern United States.