Resistance to the sugarcane borer (Lepidoptera: Crambidae) in Louisiana sugarcane cultivars

Authors: SALGADO, LEONARDO - LSU Agcenter; WILSON, BLAKE - LSU Agcenter; VILLEGAS, JAMES - LSU Agcenter; Richard, Randy; Penn, Hannah

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2021
Publication Date: 11/3/2021
Citation: Salgado, L.D., Wilson, B.E., Villegas, J.M., Richard, R.T., Penn, H. 2021. Resistance to the sugarcane borer (Lepidoptera: Crambidae) in Louisiana sugarcane cultivars. Environmental Entomology. 51(1):196-203. https://doi.org/10.1093/ee/nvab118.
DOI: https://doi.org/10.1093/ee/nvab118

Interpretive Summary: The sugarcane borer is the primary insect pest in Louisiana sugarcane production. Currently, there are several breeding programs established to develop sugarcane varieties that are less likely to lose yield due to sugarcane borers, but the particular reasons the selected plants can resist such damage are relatively understudied. These mechanisms were evaluated by comparing sugarcane varieties with different levels of sugarcane borer resistance in a field setting mimicking commercial practices, control greenhouse experiments, and laboratory study of sugarcane borer diet preferences. We found that the currently grown commercial varieties HoCP 85-845 and HoCP 04-838 and L 01-299 experienced the least amount of borer-related damage while HoCP 00-950 and L 12-201 had the greatest level of damage. Sugarcane borer damage appears to be related not to parent preference for egg-laying sites but the ability of newly hatched borers to survive in the particular varieties of sugarcane. This may be due to differences in rind hardness of the sugarcane varieties, but further work is needed to establish the precise plant characteristics responsible for sugarcane borer resistance.

Technical Abstract: Cultivar resistance is a key management strategy for the sugarcane borer, Diatraea saccharalis (F.), in Louisiana sugarcane, but mechanisms of resistance are not well understood. This research evaluated the potential mechanisms of cultivar resistance to D. saccharalis among commercially produced sugarcane cultivars and experimental lines through three field screenings, two greenhouse experiments, and one diet incorporation assay. The resistant standard HoCP 85-845 and HoCP 04-838 and L 01-299 were among the cultivars with the lowest D. saccharalis injury levels in both field and greenhouse trials. Cultivars HoCP 00-950 and L 12-201 were among the most heavily injured in both trials. Differences in oviposition among cultivars in the greenhouse choice study were not detected, suggesting adult preference is not a key factor in resistance. This was also supported by the no-choice greenhouse experiment in which up to 9-fold differences in neonate establishment among cultivars were detected. Larval injury among cultivars in greenhouse experiments was consistent with field studies suggesting traits which affect neonate establishment (eg. rind hardness) help to confer resistance in the field. In the diet incorporation assay, lower larval weights and longer time to pupation were observed on resistant cultivar Ho 08-9003, but no differences were found among current commercial cultivars. Continuous evaluation of cultivar resistance to D. saccharalis is important in developing effective integrated pest management strategies for this pest. More research into plant characteristics associated with resistance is needed.