The Southern Chinch Bug, Blissus insularis, is the most destructive pest of St. Augustinegrass throughout its area of adaptation in the U.S. 'Floratam' St. Augustinegrass was developed and deployed in 1973 with 80% to 100% antibiosis to this pest. 'FX-10' was developed and released in Florida also with high antibiosis in 1993. The resistance in Floratam was lost in Florida in 1985. In 2005 an apparent new biotype of virulent bugs (VTSCB-2005) was identified in southern Texas that was unaffected by the resistance in either Floratam or in FX-10. In at least two different experiments both of these cultivars only killed 20% or less of the confined adult chinch bugs within a 7-day feeding period in the laboratory. Additional commercial cultivars ('Delmar', 'Mercedes', 'Palmetto', 'Raleigh', 'Seville', 'Winchester' and 'Texas Common') were all highly susceptible to the new biotype. However, several new hybrid breeding lines exhibited greater than 65% kill of the confined bugs in replicated no-choice feeding studied. Two of the hybrids provided 74 and 83% mortality of the chinch bugs and are being considered for further development.