Southern Chinch Bug Resistance in St. Augustine-grass12

Abstract

Sixteen accessions of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, were evaluated for resistance to Blissus insularis Barber under heavy population densities in the laboratory. The grasses, FA-108, Floratam (FA-110), and FA-110, exhibited antibiosis and killed 57.66, 56.35, and 48.91%, respectively, of the adult population in 4 days. Antibiosis of 5th instars of 90.7, 89.8, and 71.1%, respectively, was exhibited by the same 3 accessions in 7 days. Of the remaining population of 5th instars, only 25–60% reached the imago in 7 days as compared to 98.2% for those confined on common St. Augustinegrass. Fecundity of adults was significantly reduced when they were confined on the resistant selections; 5 females produced an average of 9.75 eggs/stolon on Floratam whereas 42.75 eggs/stolon were produced when confined on common, which is very susceptible to chinch bug feeding and was used as a standard in these tests. Several other accessions, including Floratine, also showed considerable tolerance to southern chinch bug feeding.