Evaluation of Resistance to the Mexican Rice Borer Among Commercial and Experimental Sugarcane Cultivars, Beaumont, TX, 2016

A study was conducted in 2016 at the Texas A&M AgriLife Research and Extension Center at Beaumont (Jefferson Co., TX) to evaluate the resistance of 12 sugarcane cultivars to the Mexican rice borer, Eoreuma loftini (Lepidoptera: Crambidae). Cultivars were planted on 1 Sep 2015 to single row plots (12-ft long each) with 6-ft alleys arranged in a randomized complete block design with five replications. Standard sugarcane production practices were followed throughout the growing season and plots were exposed to natural E. loftini infestations. Plants were harvested on 19 Oct 2016. Fifteen stalks were randomly selected from each plot. The numbers of internodes, bored internodes, and adult emergence holes were recorded. Data were analyzed using generalized linear mixed models (PROC GLIMMIX, SAS Institute). Kenward–Roger method was used to calculate error degrees of freedom and means were separated using Tukey’s HSD (α = 0.05).

The percentage of bored internodes varied among sugarcane cultivars and ranged from 0.8% (HoCP 85-845) to 5.7% (L 09-840) (Table 1. Cultivars which are known to be highly susceptible, HoCP 04-838 and HoCP 00-950, were among the most injured in the test. Recently released commercial varieties, Ho 07-613 and L 09-804, displayed moderate levels of resistance. The most widely planted commercial cultivar in Louisiana, L 01-299, and resistant standard, HoCP 85-845, had the lowest levels of injury. Experimental cultivar L 09-840 demonstrated the greatest susceptibility and has now been eliminated from consideration for commercial release.

Adult emergence per stalk ranged from 0.03 to 0.28, but differences among cultivars were not detected (Table 1).

This research is supported by funding from the American Sugar Cane League.