Trap cropping, planting date, and cowpea variety as potential elements of an integrated pest management strategy for Lygus hesperus in blackeyed cowpea

The western tarnished plant bug, Lygus hesperus (Hemiptera: Miridae), is a serious agricultural pest that is increasingly difficult to control in blackeyed cowpea (Vigna unguiculata L. Walp). In a 2-year field study, we evaluated the potential of three cultural practices as part of an integrated pest management (IPM) strategy for L. hesperus in cowpea. We tested the utility of a trap crop in attracting L. hesperus from cowpea plots, explored the use of alternative planting dates to dissociate insect abundance from sensitive crop phenological periods, and tested the performance of two cowpea varieties of differing growth habits. We hypothesized that trap cropping and a planting date modification would reduce L. hesperus abundance in the crop plots and consequently reduce damage and that the two cowpea varieties would respond differently to L. hesperus pressure. Trap rows hosted more L. hesperus than did cowpea plots in some instances, although this effect did not translate to differences between cowpea plots with and without trap crop rows or to an increase in cowpea yield. Planting date affected L. hesperus abundance and crop yield in both years, although the specific effects of planting date differed between years. Early-planted plots yielded less seed in the first year and more seed in the second year than late-planted plots. The strongest differences in insect abundance patterns over time were measured between the two cowpea varieties and suggest that more upright varieties may be less preferable to L. hesperus than the standard cowpea varieties used today. An IPM strategy for L. hesperus in blackeyed cowpea should incorporate a well-timed planting date and well-chosen cowpea variety. Trap cropping may work to attract L. hesperus from the cowpeas, but this management strategy will require further development to be consistently effective.