Field abundance and spatial patterns of ear-feeding insect pests in relation to levels of defective kernels in...

In this study, we investigated the within-field distribution of sweet corn insect pests in relation to adjacent habitats and determined the level and specific causes of defective kernels affecting the quality of the final product at the processing cannery. Sap beetles [primarily Carpophilus lugubris (Murray, 1864) (Coleoptera: Nitidulidae)] and stink bugs [primarily Euschistus servus (Say) ((Heteroptera: Pentatomidae)] infested 27.6% and 73.6% of the fields, respectively. Densities of stink bugs were highest along field edges adjacent to wheat, soybean, vegetable crops, and woodlots. Levels of kernel injury were consistently higher in truckloads of ears harvested first from the outer rows. Earworm damage was confined to the ear tip and had no measurable impact on the quality of the final product. Sap beetles and blemished kernels were the major causes of defective kernels in the cannery, even though stink bugs were more abundant in the fields. Defective kernels were more positively related to physiological blemishes than to other causal factors. For all fields, defective kernel levels averaged less than 1%, resulting in excellent quality of the processed product throughout the entire season. Results provided a better understanding of the quality control issues, resulting in practical implications for improvements in field monitoring and decision-making in the cannery to minimize grading problems.