Association between Blissus insularis Densities and St. Augustinegrass Lawn Parameters in Florida

Abstract

Core Ideas Cultural control of southern chinch bug in St. Augustinegrass by following recommended guidelines for mowing heights based on turfgrass cultivar, and practicing thatch management may reduce insecticide use and nontarget impacts. Turf parameters (turf height and thatch thickness) were closely associated to southern chinch bug densities observed in St. Augustinegrass residential lawns. Best management practices recommended for growing St. Augustinegrass in Florida may help to maintain a balance between turf health and pest pressure. Turf characteristics in conjunction with environmental factors influence the microclimate suitability for insect pest survival in grasses. In this study, we sought to find the association between southern chinch bug (Blissus insularis) densities, St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] health characteristics (weed abundance, turf density and height, turf color, chlorophyll content, total Kjeldahl nitrogen concentration, and thatch thickness), and abiotic factors (soil pH, soil and air temperature, soil moisture, and light intensity) by sampling residential lawns in Alachua and Marion counties, Florida. A 2‐year study was conducted: approximately 90 St. Augustinegrass lawns were selected for monthly sampling in May and June 2011. This was followed by weekly sampling in 17 selected lawns in July and August 2011 and 13 lawns in June to August 2012, respectively. Results from lawn surveys indicated that light intensity (r = 0.30, P = 0.0034), and thatch thickness (r = 0.22, P = 0.0390) were positively associated with B. insularis densities. The inverse relationship between turf color and B. insularis densities indicated the impact of insect feeding damage. A significant positive association of insect abundance with grass height and thatch thickness identified the need for turf management practices (mowing at recommended cut height and verticutting/thatch removal) to reduce habitat suitability for insect pest survival.