Influence of commercially available wildflower mixes on beneficial arthropod abundance and predation in turfgrass

Abstract

Conservation and augmentation of indigenous natural enemies are promising strategies for biologically based pest management in outdoor urban environments. This research sought to determine whether the addition of wildflower plantings would enhance the occurrence, abundance and impact of beneficial arthropods in the landscape, and to determine the potential compatibility of pest-resistant turfgrass and natural control of Japanese beetle, Popillia japonica Newman, and fall armyworm, Spodoptera frugiperda (J.E. Smith). A bermudagrass cultivar (susceptible to fall armyworm), a zoysiagrass cultivar (resistant to fall armyworm), and two different commercially available wildflower mixes all harbored a diverse array of beneficial arthropods in both large and small plot evaluations. A wildflower mix containing 15 species of flowers provided significant, season-long increases in foliar-dwelling spiders and bigeyed bugs during 1-yr of a 2-yr study in large (1,512 m2) plots. Ground-dwelling spiders were more abundant in bermudagrass turfgrass than in wildflowers both years, whereas ants were not significantly affected by cover type. Each wildfiower mix evaluated in a separate 2-yr small plot study increased the abundance of some, but not all beneficial arthropod taxa sampled. This increased abundance was only occasionally also observed in adjacent turfgrass areas. However, fall armyworm eggs and larvae, and Japanese beetle eggs were consistently and heavily preyed upon in small plots regardless of turfgrass species in the plot or surrounding border of flowers or mulch. Most beneficial taxa, even Geocoris uliginosus, which was more common in turfgrass, were represented in flowers, suggesting that these floral plantings may be useful in providing refugia for beneficials when insecticide applications are required to suppress turfgrass pests.