Resistance to stem borers (Lepidoptera: Crambidae) among Texas rice cultivars

A 4-yr field study was conducted to assess the resistance of rice, Oryza sativa L., cultivars to injury from the sugarcane borer, Diatraea saccharalis (F.), and the Mexican rice borer, Eoreuma loftini (Dyar) (both Lepidoptera: Crambidae). Several cultivars showed reduced levels of injury ('CLXL8', 'XL8', 'Wells', 'Cheniere', and 'XP710' in 2003; CLXL8, XP723, Cheniere, and 'CL161' in 2004) and lower stem borer yield loss (CLXL8 in 2004) than the more susceptible 'Priscilla'. The resistant CLXL8 also had less injury and yield loss in 2004 and higher yield in 2003 than 'Cocodrie', currently the most popular rice cultivar in Texas and Louisiana. Linear regression analyses between whiteheads and main crop rice yield showed steeper negative slopes for the more resistant cultivars than the more susceptible cultivars, indicating a greater yield loss per whitehead on the resistant cultivars. Compensation from insect injury likely explains the positive associations established in our study between main crop yield and whiteheads for some cultivars. Cultivar resistance is anticipated to become a major control tactic in reducing infestations of E. loftini and D. saccharalis in the Texas and Louisiana rice industries.