Reevaluating the Economic Injury Level for Brown Stink Bug (Hemiptera: Pentatomidae) at Various Growth Stages of Maize

Abstract

Economic yield loss and reduction in grain quality from brown stink bug, Euschistus servus (Say), feeding injury in early and late stages of maize, Zea mays (Poales: Poaceae, Linnaeus), development was assessed in Virginia and North Carolina in 2018 and 2019. Varying levels of stink bug infestations were introduced to seedling maize (V2—early stage), and a range of late-stages of maize, including 1) the last stage of vegetative development (V12/V14), 2) prior to tasseling, 3) at tasseling (VT), and 4) across all tested late growth stages. Euschistus servus infestation levels included 33, 67, and 100% of maize seedlings, and 25, 50, 100, and 200% of plants during later stages. Infestations were maintained on seedling maize for 7 d, and 8 or 16 d in reproductive stages. Infestation level in seedling maize had an impact on grain yield. Infestation level and growth stage both had an impact on grain yield in reproductive maize. The percentage of discolored kernels was also affected by infestation level, but not growth stage. Regression analysis between grain yield and infestation level indicated that the average economic injury level is 7% in seedling maize (7 bugs/100 plants) and 12% (12 bugs/100 plants) from the last vegetative stages (V12/V14) through pollination (VT). The economic injury level in the late vegetative stages is only applicable when infestations are present for an extended period of time (16 d), emphasizing the need for continued scouting of maize throughout the season to make informed management decisions.

Plant-host shift, spatial persistence, and the viability of an invasive insect population

“…Considered in an applied scenario, the movement of pests between different patches can result in damaging economic losses. In pest control programs the aim is to present actions that maintain the density of pests in an equilibrium level below damaging economic thresholds (Zhang et al, 2018;Wieser et al, 2019;Bryant et al, 2020), so the analysis of parameter values that lead to the loss of stability, resulting in unpredictable population outbreaks, has an unquestionable utility for integrated pest management strategies (Costa & Faria, 2010). The ecological interactions between different species of drosophilids and their varied food sources have been systematically studied in the past (Buruga & Olembo 1971), due to the importance of these species in attacking ripening fruit.…”

Selection of insecticides, determitionof applying timing and times, and establishment of dynamic economic threshold on sweet corn for the invasive Spodoptera frugiperda in tropical Asia

“…I×D was the regression slope between pest density and corn yield. In this experiment, we assumed an insecticide application provides full FAW control i.e., K = 1 (Bryant et al 2020). The cost of insecticide application (i.e., product and application cost) was determined as above.…”

Removing neonicotinoid seed treatments has negligible effects on refuge function and crop protection in transgenic maize targeting western corn rootworm (Coleoptera: Chrysomelidae)

“…Harvested ears were air dried until moisture content reached 10–20%. Grain yield was measured using methods adapted from Bryant et al (2020). On all harvested ears, we determined: i) number of kernel rows, ii) number of kernels per row, iii) average kernel weight, and iv) % moisture.…”