Japanese Beetle Biocontrol
The MN Department of Agriculture and the MN Department of Natural Resources list Japanese beetle (JB, Popillia japonica) as a highly destructive, invasive exotic pest (USDA 2017, CAB 2005). Since introduced from Japan in 1916, JB defoliates over 300 plant species, including, linden trees, basswood trees, apples, corn, and soybean. Adult beetles can aggregate on leaves and fruits and feed in large numbers, that renders the fruit unmarketable. In addition, the immature grub stage feeds on the roots of grasses in pastures, green space, and recreational turf. Japanese beetle damages owers, fruits, and foliage which results in fewer owers and less food for bees, as well as less fruits for wildlife. However, the spraying of insecticides on bee lawns for JB grubs and on plants and owers for adults, probably results in the more pollinator deaths. Fortunately, JB has a natural biocontrol agent that was discovered in 1988 in Connecticut killing JB grubs (Hanula and Andreadis 1988) that needs to be introduced into MN. The microsporidian (fungal) pathogen called Ovavesicula popilliae was studied at Michigan State University (MSU) (Perry et al. 2013, Smitley 2011) and released in four states. MSU identied the pathogen in MN JB. For the long term, research is needed to survey greater MN for the presence of JB and the pathogen, which so far was found in one location in MN. For the short term, IPM programs need to be developed that conserve pollinators and manage JB.The purpose of this research is to develop new management tactics to reduce economic and environmental damage caused by the exotic JB. The outcome is to reduce JB numbers locally and to slow its spread around the state of MN.