Developing a sampling plan for brown stink bug (hemiptera: Pentatomidae) in field corn

Abstract

Brown stink bug, Euschistus servus (Say), is a damaging pest of corn, Zea mays (L.), in the southeastern United States. Developing a reliable and practical sampling plan for population monitoring of this pest is essential for implementing integrated pest management measures. E. servus was sampled from commercial corn fields (n = 14) in North Carolina in 2016 and 2017. Both the adults and nymphs had a predominantly aggregated spatial distribution, estimated using the variance to mean ratio and Taylor's power law constant (b). Using the Taylor's power law constants, the optimum sample size required to estimate population density with a given level of reliability was calculated. For early vegetative stage corn (V4-V6), using whole plant visual sampling and an economic threshold density of 2 adult stink bugs per 20 plants, 27 sample units were required to estimate population density within 30% of the mean. At the same growth stage, using partial plant sampling and an economic threshold density of 1.73 adult stink bugs per 20 plants, 28 sample units were required to estimate population density with the same level of reliability. Reproductive stage corn (R1-R4) required eight sample units for whole plant sampling and nine sample units for partial plant sampling (Dx = 0.3). For E. servus adults, the partial plant sampling method was equally or more cost-reliable than the whole-plant sampling method for pest management in all corn growth stages tested.