Popillia Japonica, commonly known as the Japanese Beetle, is a destructive, invasive pest in Canada. About 15 mm long and 10 mm wide, it has an iridescent, copper-coloured elytra, and green thorax and head.
It is not a destructive pest in Japan because it has natural predators that keep its numbers under control. One such predator is the Anchor bug, commonly known as the stink bug.
In Canada, however, the Japanese Beetle has no natural predator and causes much damage, destroying strawberries, cherries, hops, beans, peaches, peas, plums, grapes, rose bushes, and other common and important crops. It causes damage by skeletonising the foliage, i.e. consuming only the leaf material between the veins.
The Japanese beetle came to Canada in 1939, in a tourist’s car that entered Yarmouth, Nova Scotia, from Maine in the US. It was first discovered in the US in 1916. It is believed to have entered the US as larvae in a shipment of Iris bulbs, before 1912, as the inspection of commodities entering the US did not begin until 1912.
Today, an effective biological agent has been found in the spring Tiphia wasp. It reduces significantly the population of Japanese beetles, but has not eradicated it.
A home remedy for getting rid of Japanese beetles that attack garden rose bushes, is to hand pick the beetles off the plant, and drop them in a jar of soapy water which kills them. This does not, unfortunately, guarantee their disappearance from the garden.
