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Japanese beetle adults are about 1/2 in. (13 mm) long with a metallic green head and thorax, and reddish-brown wing covers.
Usually complete about one generation per year, although a full life cycle may take two years in the coldest regions of Japanese beetle distribution.
Mating occurs as soon as females emerge from the ground. Then, they seek grassy areas with moist soil to lay eggs.
Eggs are .04 inches to .08 inches (1 mm to 2 mm) in diameter, spherical and white, and are laid about 2 inches to 4 inches (5 cm to 10 cm) deep in the soil in batches throughout the female beetle’s month-long life.
C-shaped, cream-colored grubs with brown heads and three pairs of legs develop in the soil, becoming 1.18 inches (3 cm) long when fully grown.
Eggs are laid in the ground; the small, white larvae, called grubs, feed on the roots of grasses.
Larvae sometimes kill roots of grasses they feed on.
Adults destroy leaves, flowers and fruits they feed on.
Beetles are best detected on blueberry bushes during calm, hot, cloudless afternoons.
Traps for monitoring Japanese beetle are highly attractive but can increase the number of beetles flying into an area.
In small plantings, beetles can be removed from bushes.
Control of attractive weed hosts and removal of grassy areas in and around fields can reduce field suitability for Japanese beetles.
Biological control agents suppress populations in areas where the beetle is established.
Check with your local Cooperative Extension Service office for control measures recommended for your area.