Feedstock crops selected for bioenergy production to date are almost exclusively perennial grasses because of favorable physiological traits that enhance growth, water use, and nutrient assimilation efficiency. Grasses, however, tend to rely primarily on physical defenses, such as silica, to deter herbivores. Silica impedes processing of feedstocks and introduces a trade-off between managing for cost efficiency (i.e., yield) and plant defenses. To test how silica modulates herbivory in two of the most preferred feedstock crops for production across the central United States, miscanthus (Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize) and switchgrass (Panicum virgatum L.), we examined the performance of two immature generalist insect herbivores, fall armyworm (Spodoptera frugiperda (J.E. Smith) and the American grasshopper [Schistocerca americana (Drury)], on grasses grown under silica and nitrogen amendment. Both miscanthus and switchgrass assimilated nitrogen and silica when grown in amended soil that altered the consumption and conversion efficiency of herbivores consuming leaf tissue. The magnitude of nutrient assimilation, however, depended on intrinsic plant traits. Nitrogen increased conversion efficiency for both fall armyworm and American grasshopper but increased consumption rate only for fall armyworm. Silica reduced conversion efficiency and increased consumption rate only for the American grasshopper. Because of this variability, management strategies that reduce silica or increase nitrogen content in feedstock crops to enhance yields may directly influence the ability of bioenergy grasses to deter certain generalist herbivores.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 105 • No. 3