The Japanese beetle (Popillia japonica) is another invasive scarab beetle species. Adults first emerge from the soil early in July and immediately go on a 30–45 day long feeding spree, damaging the foliage, flowers and fruit of trees and shrubs nearby. The females then burrow underground to lay their eggs, which hatch into small white grubs two weeks later. The grubs feed on plant roots as far as 10 cm below ground, but they’re primarily active near the soil surface in spring and fall. When ground temperatures drops below 15 °C, the grubs descend deep into the soil to overwinter (typically in October). In spring of the following year, when the temperature rises again (in late April or early May), the larvae return to the surface to feed until they finally pupate around mid-June and then emerge a few weeks later as adults to produce the next generation of beetles.
What kinds of plants do they attack?
Japanese beetle grubs cause considerable damage to turf grass, and the adults are serious pests of a wide variety of fruit and ornamental trees and shrubs, especially: apples, cherries, grapes, linden, maples, peaches and roses.
What do they look like, and how do I know if my plants are under attack?
The adult Japanese beetle is very distinctive in terms of appearance; it has a metallic green head and thorax, bronze wing covers and six white tufts of hair along each side of its abdomen. They can be seen in large numbers all over the trees and shrubs they attack. The presence of adult beetles on these plants is also a sure sign that they have infested any grassy areas nearby with their white grub larvae.
Please consult the general information on white grubs for more information.
How to get rid of Japanese beetle
Koppert offers different solutions for biological pest control of Japanese beetle.