TY - JOUR
T1 - A field test on the effectiveness of milfoil weevil for controlling Eurasian watermilfoil in Wisconsin lakes
AU - Havel, John E.
AU - Knight, Susan E.
AU - Maxson, Kristopher A.
N1 - Funding Information:
We thank Kevin Gauthier for suggesting the project and facilitating discussions with participating lake associations and with EnviroScience. We also thank J. Heywood and L. Morrison for helpful discussion of experimental design, and C. Marquette for information on weevil biology and the rearing method used by EnviroScience. Onterra LLC provided invaluable assistance with bed mapping and area determination in 2012 and advice on area estimation in other years. We especially thank student workers, J. Bevington, E. Fruhling, C. Kruger, V. Jones, J. Miazga, C. Winter, and N. Winter, who assisted with field collections and laboratory analysis. Comments from L. Morrison and two anonymous reviewers helped us refine the paper. Logistical support was provided by the UW-Madison Center for Limnology and Trout Lake Station and financial support by a grant from the Wisconsin Department of Natural Resources (Grant ACE-122-12).
Publisher Copyright:
© 2017, Springer International Publishing Switzerland.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - We tested the effectiveness of milfoil weevils (Euhrychiopsis lecontei) for reducing biomass of Eurasian watermilfoil (Myriophyllum spicatum, EWM) under natural lake conditions in a 3-year field experiment. In each of four lakes, we randomly chose two EWM beds for stocking and two beds as controls. A total of ca. 40,000 weevils were added to the eight stocked beds. During June and August 2013–2015, we measured plant diversity, biomass of EWM and native plants, and weevil abundance in the 16 study beds. Background weevil densities varied widely among beds and were often greater than the densities stocked. Weevil stocking had no significant effect on EWM or native plant biomass. Nevertheless, weevil damage to EWM was common and its extent appeared strongly related to observed densities of the weevil. ANCOVA results indicated that weevil density was a significant predictor of EWM biomass in both June and August, but not on growth during summer. Overall, our study found that weevil density is an important factor for predicting EWM biomass, while weevil density is likely affected by a large number of environmental factors. This work highlights the importance of carefully considering lake conditions that may influence the efficacy of stocking for biological control.
AB - We tested the effectiveness of milfoil weevils (Euhrychiopsis lecontei) for reducing biomass of Eurasian watermilfoil (Myriophyllum spicatum, EWM) under natural lake conditions in a 3-year field experiment. In each of four lakes, we randomly chose two EWM beds for stocking and two beds as controls. A total of ca. 40,000 weevils were added to the eight stocked beds. During June and August 2013–2015, we measured plant diversity, biomass of EWM and native plants, and weevil abundance in the 16 study beds. Background weevil densities varied widely among beds and were often greater than the densities stocked. Weevil stocking had no significant effect on EWM or native plant biomass. Nevertheless, weevil damage to EWM was common and its extent appeared strongly related to observed densities of the weevil. ANCOVA results indicated that weevil density was a significant predictor of EWM biomass in both June and August, but not on growth during summer. Overall, our study found that weevil density is an important factor for predicting EWM biomass, while weevil density is likely affected by a large number of environmental factors. This work highlights the importance of carefully considering lake conditions that may influence the efficacy of stocking for biological control.
KW - INHS
KW - Myriophyllum spicatum
KW - Aquatic invasive species
KW - Augmentative biological control
KW - Euhrychiopsis lecontei
KW - Lake management
KW - Invasive aquatic plants
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U2 - 10.1007/s10750-017-3142-2
DO - 10.1007/s10750-017-3142-2
M3 - Article
SN - 0018-8158
VL - 800
SP - 81
EP - 97
JO - Hydrobiologia
JF - Hydrobiologia
IS - 1
ER -