pdf W2 Jun2001ProgRep

Factors Influencing the Control of Eurasian Watermilfoil With Native Or Naturalized Insects


Authors: Raymond M. Newman1, David W. Ragsdale2 & David D. Biesboer3

Author Affiliation: 1Department of Fisheries & Wildlife; 2Department of Entomology; 3Department of Plant Biology University of Minnesota St. Paul, MN 55108

Journal: Minnesota Department of Natural Resources, Fourth Status Report for 1999-2001

Abstract: Although declines of milfoil in several lakes have been related to the occurrence of E. lecontei, it is clear that at many sites in Minnesota, weevil densities do not get high enough to effect control. Fish predation may be one factor limiting populations in some lakes.
The aim of this project is to monitor a set of milfoil populations for potential declines, determine factors that may be limiting control agent densities and their effectiveness in the field, determine the effects of fish on weevil augmentations and determine if chronic effects such as sediment quality or competition with native plants is responsible for declines of milfoil associated with herbivores. This report summarizes our methods and collection efforts in 2000 and presents preliminary results of our research through 2000.