JAPANESE BEETLE AT A GLANCE COMMON NAME: Japanese
beetle
DESCRIPTION: Half-inch long, metallic green beetles with coppery wings; C-shaped grubs
which grow into beetles are whitish, up to 1-inch long.
PARTS ATTACKED: Beetles chomp leaves, flowers and fruits of more than 275 plant
species, most everything except vegetables, late June and early July.
DAMAGE: Adults skeletonize leaves and eat flowers and fruits. Larvae cause brown
patches of lawn to roll up like carpet.
LIFE: Grubs spend most of year deep in soil; early spring they feed near surface and
pupate, or go through the larval stage. In summer, adults feed for about 6 weeks, then lay
eggs in soil. Cycle can take two years.
CONTROLS: Hand pick, especially beneficial for female beetles because they feed only a
few days before laying eggs; organic Milky Spore application on lawn to kill grubs but
also affects earthworms; parasitic nematodes, which are beneficial microscopic worms that
feed on soil pests. Spray heavy infestations with Sevin according to label directions, or
use a botanical insecticide such as neem or pyrethrum. Horticulturists caution against
traps, which use a female sexual attractant (called pheromone) to attract the males and
can attract more beetles than they can handle. If you use traps, place them far, far away
from your plants. Beetles known to play dead when disturbed so shake onto a cloth and
destroy by placing them in a can of soapy water. Starlings eat adult beetles; robins and
starlings eat larvae. Mature, healthy plants generally recover so let nature take its
course. Last year's drought adversely affected the water-dependent beetles, meaning there
should have been fewer larvae to overwinter in the soil and emerge as adult beetles this
year, says Pete Schultz, director of the Hampton Roads Agricultural Research and Extension
Center in Virginia Beach.
Sources: Sunset Garden Pests and Diseases, Complete Guide to Pest Control |