Faculty Mentor

Paul J. Johnson, Susan Rupp


Switchgrass (Panicum virgatum) is growing in recognition as a potential source for biomass. In order to use switchgrass optimally as a crop for biofuel production potential pests need to be detected and studied. Currently, one pest being studied is the stem-boring larva of the moth Blastobasis repartella. The objective of this experiment was to compare effects of larval feeding on rhizome buds for two cultivars of switchgrass, and to observe and document feeding behavior of the larva. The two cultivars of switchgrass used were Pathfinder (PTH), a lowland variety, and Sunburst (SBS), an upland variety. Six, 15-cm2 samples of rhizome clusters from each cultivar were taken in September 2011 from South Dakota State University’s Aurora Research Farm. A total of 136 tillers were collected from both varieties containing 345 buds; 114 of those buds were killed by B. repartella. Pathfinder rhizome samples produced 25 larvae while those of Sunburst had 22 larvae. No significant differences were detected between PTH and SBS in regards to the number of new buds present, the number of damaged buds, the number of larvae, or the rate of damage caused by larvae. It appears that B. repartella larvae do similar amounts of damage to both varieties and that there is a significant pest status with approximately one-third of the potential biomass producing buds being killed.



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