BEETLES
Japanese beetles - a very
close relative of Hoplia
(Photo courtesy of Missouri
Botanical Garden PlantFinder)
Hoplia Beetle
The hoplia beetle, Hoplia callipyge is a
very close relative of the Japanese beetle. The larvae feed on decaying
vegetation and plant roots. Hoplia remain in the larval or pupal stage
throughout the winter. In early spring they complete development and adult
beetles emerge from the soil. Hoplia beetle adults are especially attracted
to light-colored flowers and chew round holes in the petals. Early buds and
flowers may be destroyed. The beetles do not feed on leaves.
One way to manage hoplia beetles in your garden
is to regularly hand-pick them off the flowers they are feeding on and
dispose of them. You can also clip off infested blooms and dispose of them.
It is very difficult to obtain effective control with insecticides because
beetles are protected within the blossoms and they must be contacted
directly by the spray to be killed. Limited success can be found with chemicals
such as Orthene
, Tempo , Merit , Talstar , Malathion , Azatin EC , Pyrellin , Sevin or pyrethroid cyfluthrin.
These insecticides only kill those beetles present at the time of the spray
applications. Read
the insecticide label throroughly, as some insecticides such as diazinon can
cause phytotoxic reactions to new foliage if applied when the weather
temperatures are above 80 degrees F.
Carrot beetle—Ligyrus gibbosus
Carrot beetles have a longer life than Hoplia
beetles, but they are not as prevalent in our area. They feed on irises,
both above and below ground. Larvae are up to 1-1/4 inches long,
white to bluish, and have a dark head. Adults are reddish brown, 1/2-inch
long. Carrot beetles cause the foliage to turn yellow and wilt. Plants may
be stunted, fall over or die if the beetles attack the roots. The basal
stems or leaves may also be chewed.
A somewhat successful control of carrot beetles
can be accomplished with Malathion. Remember, as with the Hoplia beetles,
the insecticide must come into direct contact with the beetle to be
effective.
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