Creed, R.P., S.P. Sheldon, and D.M. Cheek, 1992. The Effect of Herbivore Feeding on the Buoyancy of Eurasian Watermilfoil, Appalachian State University.

Reprinted with permission from Journal of Aquatic Plant Management (1992) 30: 75-76 

The Effect of Herbivore Feeding on the Buoyancy of Eurasian Watermilfoil

Abstract 
Recent investigations examining the effects of herbivores on Eurasian watermilfoil (Myriophyllum spicatum L.), hereafter referred to as watermilfoil, have focused on the ability of these herbivores to remove leaf tissue and/or affect plant growth (Painter and McCabe 1988, MacRae et al. 1990, Creed and Sheldon 1991, 1992). We recently observed a collapse in a watermilfoil bed which suggests that some of these herbivores may have additional effects on watermilfoil. In late July of 1991, we noticed that watermilfoil plants in Brownington Pond, Vt had sunk below the water surface. The top of the west bed (see Creed and Sheldon 1991) was at least one meter below the surface of the pond; earlier in the summer the plants almost reached the surface. Inspection of the plants showed that many of the stems had been bored by larvae of the weevil Euhrychiopsis lecontei (Dietz). Other plants which showed little or no weevil damage appeared to have been pulled down by adjacent, insect-damaged plants. This observation suggested that the herbivorous weevil E. lecontei and the caterpillar Acentria nivea (Olivier), which is also present in the pond, could have an additional, negative effect on watermilfoil by reducing the buoyancy of the plants. 

Entire Paper
Contact: Robert P. Creed Jr., Appalachian State University, Department of Biology, P.O. Box 32027, Boone, NC 28608-2027
Key Words: Eurasian_watermilfoil, Biological_control, Aquatic_plant_management
Product Type: Research, Control
User Type: Resource Management