|Da silva, Jorge|
Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/27/2009
Publication Date: 3/20/2010
Publication URL: handle.nal.usda.gov/10113/42521
Citation: Zhou, M.M., Kimbeng, C.A., Da Silva, J.A., White, W.H. 2010. Cross-resistance between the Mexican Rice Borer and the Sugarcane Borer (Lepidoptera: Crambidae): A Case Study Using Sugarcane Breeding Populations. Crop Science. 50:861-869. Interpretive Summary: Insect caterpillars that bore into the stems of important grass plants such as sugarcane, rice, and corn can be serious pests of these crops if they are left uncontrolled. One of these, the sugarcane borer is a major pest of sugarcane throughout the Americas. It is the most important pest of sugarcane in Louisiana. Another such insect, the Mexican rice borer, has recently moved into Louisiana after first invading sugarcane in the Lower Rio Grande Valley of Texas in 1980. Although these two insects have many contrasts in their behavior, they do have important similarities in the behavior of the caterpillars. We hypothesize that because of these similarities, if a resistant plant is found for one species, this plant will be resistant to the other, i.e. cross-resistance. To test this hypothesis we planted an experiment in Texas where both stem borer species are present and evaluated the damage for two years. We then analyzed the data for evidence of cross-resistance. Our analysis found strong evidence for accepting our hypothesis and concluded that those varieties developed for resistance to the sugarcane borer will also be resistant to the Mexican rice borer. This is good news for plant breeders in both states as it means that dual breeding programs will not be needed to develop resistance to both species. As the Sugarcane Research Laboratory has already established a strong program for developing resistant varieties for the sugarcane borer, then resistance to the Mexican rice borer should quickly follow.
Technical Abstract: The sugarcane borer (SCB) (Diatraea saccharalis) and Mexican rice borer (MRB) (Eoreuma loftini) are two economically important pests of sugarcane in the USA. Because of similarities in larval feeding behavior, selecting for resistance to one species could provide resistance to the other, a phenomenon we have termed "cross-resistance". Thirty genotypes from Louisiana previously identified as either resistant or susceptible to the SCB and 50 from Texas with unknown resistance status to either species were evaluated for percent borer-damaged internodes. Data from the SCB-resistant and susceptible genotypes were used to determine the SCB-resistance status of all 80 genotypes. Similar (P = 0.578) levels of MRB damage was found between the Louisiana and Texas population, whereas, the Louisiana population suffered significantly (P < 0.05) less SCB damage compared to the Texas population. The SCB-resistant genotypes suffered significantly (P < 0.01) less damage from the MRB compared to their susceptible counterparts. A significant (P < 0.001) association was found in percent SCB- and MRB-damaged internodes among the Louisiana and the SCB-resistant populations but not among the Texas or SCB-susceptible populations. Furthermore, the SCB-resistant genotypes were 40% less likely than their susceptible counterparts to be bored by the MRB. Resources developed for SCB resistance could form the foundation material to breed for resistance to both pests.