The species Popillia japonica is commonly known as the Japanese beetle, which is often a destructive pest of many species of plants in Eastern Canada. The damage caused by P. japonica is sustained through the feeding of both the adult and the grub. The adult consumes the plant material resulting in ‘skeletonized’ leaves, while the grub develops within the soil, feeding on the root system of the plant, and thus, affecting plant survival and yield.
The adult Japanese beetle at maturity is approximately 2 cm long and a green metallic colour with copper brown front hard-wings (elytra). The adult beetle often emerges from the soil in early June; this is the beginning of a six week feeding period resulting in a heavy damage to the crops. The adult Japanese beetle is highly mobile and can infest adjacent fields rapidly, for which control measures must be efficient and performed timely during the season.
When scouting for the Japanese beetle it is important to identify the species as well as the level of initial damage of ‘skeletonized’ plant leaves. Depending on the crop threshold, levels change significantly – more so when crops are under other environmental stresses. A preventative control is also desirable with this pest, for which early applications or seed treatment are recommended.