Small number of traps in a home landscape can actually increase Japanese beetle problems rather than reduce them. Other control measures such as insecticide sprays and dusts may be needed to protect plants that are particularly attractive to the beetles. Traps may be effective in reducing Japanese beetle problems if used throughout a neighborhood or in open areas well away from valuable plantings or vulnerable crops. In most home landscape situations, using 1 or 2 traps probably will do more harm than good. Plant Selection Careful selection of plant species when replacing or adding to your landscape is the key to avoiding an annual battle with Japanese beetles.
Unmarked species undergo little or no feeding.
Species marked with an asterisk may suffer occasional light feeding. Beetles are fond of certain weeds and non-economic plants such as bracken, elder, multiflora rose, Indian mallow, sassafras, poison ivy, smartweed, wild fox grape and wild summer grape. Elimination of these plants whenever practical destroys these continuous sources of infestation. Repeated applications may be necessary because of the relatively short residual effect of the products. Also, a significant rainfall shortly after an application may reduce the insecticide deposit below effective levels.