Association between B. insularis population densities and St. Augustine grass health in home lawns

The southern chinch bug, B. insularis Barber (Hemiptera:Blissidae) is the most destructive insect pest of St. Augustinegrass and cause severe damage when its population reaches high densities by killing grass in small patches or entire lawn (Reinert and Kerr 1973). Excessive nitrogen inputs, drought stress and thatch thickness are believed to promote this pest problem. Data supporting how these factors influence insect populations in the field, can help modifying the cultural practices to reduce B. insularis damage. Through a 45 question survey and sampling of the respondents’ St. Augustinegrass lawns, we sought to identify various factors associated with B. insularis density. Survey questions included demographics, type, amount, and frequency of fertilization and irrigation and/ or any environment concern of homeowners. Around 150 homeowners responded to this survey but only 103 lawns were selected based on the criteria of good cover of St. Augustinegrass in their home lawns. Lawn samplings were done for turf health parameters (e.g., grass height, density, TKN content, turf color, chlorophyll content, soil temperature, moisture, pH and thatch thickness, etc.) from May to August 2011. Twenty one percent of lawns had less than 100 m2 area under turfgrass, 62% of lawns had 101- 200 m2 and 17% lawns had more than 200 m2 under turfgrass. Twenty five percent of these lawns were under lawn care services or homeowners association’s maintenance practices. Thirty two percent of these lawns were infested with B. insularis and only 13% of lawns had > 25 B. insularis per 0.092 m2 area.