Manipulation of natural enemies of key arthropod pests in Oklahoma vineyards

Taxonomically diverse arthropod pests are economically important for Oklahoma grape production, including those that sometimes serve as vectors of plant pathogens like Pierce’s disease. Integrated pest management (IPM) strategies include conservation of natural enemies (predators and parasitoids) via habitat manipulation, which can incorporate companion plants between vine rows that serve as refugia and pollen/nectar sources for adult natural enemies. This study has two primary objectives. First, we attempted to manipulate the diversity and abundance of natural enemies using ornamental plants between rows. We compared predator and parasitoid abundance and diversity in response to three treatments of between-row plantings: 1) native flowering perennials, including Achillea millefolium ‘Moonshine’, Asclepias tuberosa, and Coreopsis lanceolata; 2) Upright grass, Miscanthus sinensis; and 3) pre-existing bermudagrass as a control. Our second objective is to gain a better understanding of the natural enemy activity in the vineyard using sentinel egg masses of black cutworm (Agrotis ipsilon) placed on vines in the flower, grass, and control treatments. Preliminary results have not shown a statistical difference in total natural enemy abundance in the flowering plant treatment compared to the upright grass treatment and bermudagrass control; however, we found significant differences in parasitism and predation rates on sentinel egg masses between flowering and control treatments.