Let's delve a little further into Japanese beetle feeding
patterns. As many now know, the beetles give off a pheromone
when feeding that attracts other beetles to feed in the same
area of a plant. That's why it is said that they feed in hoards.
Another factor is what the plant is. Usually, red maple, silver
maple, boxwood, shagbark hickory, flowering dogwood, persimmon,
euonymus, white and green ash, holly, butternut, tulip tree,
sweet gum, magnolia, white poplar, common pear, white oak,
scarlet oak, red oak, and common lilac are relatively free of
feeding. Box elder, black oak and American elder usually have
light feeding. Japanese maple, Norway maple, horse chestnut,
hollyhock, gray birch, American chestnut, rose of Sharon, shrub
Althea, black walnut, flowering crab apple, apple, London plane,
Lombardy poplar, cherry, black cherry, plum, peach, apricot,
roses, sassafras, mountain ash, linden, elm and grape are nearly
always severely attacked by the adult beetles.
Also remember there is a grub stage to the Japanese beetle.
The adult beetles will be with us for a month or so; then they
lay eggs. These eggs will hatch out into a grub in early August.
Large numbers of beetles probably means a large number of grubs,
with favorable weather conditions. Treatments are the
traditional grub treatments, applied in August or early
September, or one of the alternative type applications.
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The alternative applications include "Milky Spore" dust, which is
actually a bacteria, or parasitic nematodes. The Milky Spore is a
bacteria that affects only Japanese beetle larvae (doesn't affect
other grubs) and takes a few years of fairly high numbers of
Japanese beetle grubs to distribute it well. The nematode can
occasionally be found in specialty catalogs.
Mosquito numbers are rapidly increasing. With the threat of West
Nile virus in the area, as there has been positive identification in
some surrounding counties, control becomes more of a concern. Of
course, eliminate sources of stagnant water by draining or changing
water in birdbaths, wading pools and tires. One chemical control
option is the Bt israelensis in water. This is great for ditches,
small ponds and other places where water is present all the time.
Area sprays of malathion, permethrin or tetramethrin will do quite
Cut tall grass and treat shrubs and vines, as these are resting
places for the mosquito. You can also avoid times when mosquitoes
are more prevalent, such as early morning and at dusk. Use of an
effective repellent like DEET is your best preventive when you are
in areas with many mosquitoes. The repellent will also be helpful in
preventing ticks and chiggers. With the proper precautions, you can
still enjoy the outdoors this summer.
Fulton, unit leader,
University of Illinois Extension,
Logan County Unit]