Impact of two herbivores, Samea multiplicalis (Lepidoptera: Crambidae) and Cyrtobagous salviniae (Coleoptera: Curculionidae), on Salvinia minima in south Louisiana

摘要

A field study was conducted in 2005 and 2006 to evaluate the impact of the herbivores Cyrtobagous salviniae Calder and Sands and Samea multiplicalis (Guenee) on common salvinia (Salvinia minima Baker) in south Louisiana. Our study revealed that treatments consisting of C. salviniae and S. multiplicalis feeding both independently and together significantly reduced plant biomass of common salvinia. The lowest biomass was recorded for the treatment with both C. salviniae and S. multiplicalis feeding on common salvinia in October during 2005 and 2006. Biomass showed a significant linear trend for the treatment consisting of feeding by both C. salviniae and S. multiplicalis in 2005 and significant treatment by month interaction in both 2005 and 2006. Percentage terminal-damage and percentage mat-green showed significant treatment effect in 2005 and 2006.