Targets such as flying insects, birds, and bats obscure the measurement of radar reflectivity and doppler velocity by weather radars. This study was conducted to determine the relationship of the concentration and velocity of adult bollworms, Helicoverpa zea (Boddie), and other similar-size targets with the base reflectivity and doppler velocity measured by the NEXRAD network of WSR-88D doppler weather radars. Relationships between entomological radar data, pilot balloon wind profile data, and WSR-88D reflectivity and doppler velocity data were investigated in the Lower Rio Grande Valley near the WSR-88D at Brownsville, Texas, and near the WSR-88D at New Braunfels, Texas, in the spring and summer of 1995 and 1996. Clear-air radar reflectivity often exceeded 4 dBZ, the lower reflectivity threshold on the WSR-88D radar display for precipitation-tracking mode. WSR-88D reflectivity was significantly correlated with the aerial concentration of adult bollworm-size targets. Doppler velocity was significantly correlated with the radial component of wind velocity, but the target velocity contributed to a mean bias of as much as 2.7 m/s. These results indicate that information about the local population dynamics and identity of migratory nocturnal insects can increase the accuracy of reflectivity and velocity measurements by WSR-88D radars, and lead to the development of algorithms which estimate the migratory flux of bollworms and other nocturnal insects.