Japanese's beetles will excrete pheromones, signaling others to come destroy more of the foliage they prefer.
This imported pest is generally found east of a line running from Michigan, southern Wisconsin and Illinois, south to Alabama. Occasional introductions are made into western states such as California and Oregon when the adult beetles or larvae are shipped in commerce. The original population was detected in New Jersey in 1916, having been introduced from Japan.
The adult beetles are general herbivores and are known to feed on over 400 species of broad-leaved plants, although only about 50 species are preferred. The grubs will also feed on a wide variety of plant roots including ornamental trees and shrubs, garden and truck crops, and turfgrasses. They seem to especially relish Kentucky bluegrass, perennial ryegrass, tall fescues and bentgrass.
The adults are skeletonizers, that is, they eat the leaf tissue between the leaf veins but leave the veins behind. Attacked leaves look like lace that soon withers and dies. The adults will often attack flower buds and fruit. The grubs can kill small seedling plants but most commonly damage turf. The turf first appears off-color as if under water stress. Irrigating causes a short-lasting response or no response at all. The turf feels spongy under foot and can be easily pulled back like old carpet to reveal the grubs. Large populations of grubs kill the turf in irregular patche
Sometimes after treating trees with a lot of beetles, we can hear a rain sound on the pavement. This is a light Beetle Rain, we see much heavier and hope to capture it so we can show you.