Japanese beetle adults are herbivores and are known to feed on over 400 species of broad-leaved plants. 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 eat the leaf tissue between the leaf veins but leave the veins behind. Attacked leaves look like lace that soon wither and die. 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. Grubs tunnel laterally in search of organic matter and fresh roots. This creates a very spongy feel to the soil and turf. Generally by fall, most of the grubs are ready to dig into the soil to hibernate. The grubs burrow 4 to 8 inches into the soil as cold temperatures arrive. The grubs return to the surface in the spring as the soil temperature warms. The grubs continue their development in the spring and mature in time to pupate. In about 2 weeks, the pupae become adult beetles and emerge from the ground. This life cycle takes a year.