These articles are written to apply to the northeastern
corner of Illinois. Problems and timing may not apply outside of this
a Major Vegetable Pest
May 28, 1998
Growing cucumbers or melons in your garden? The cucumber beetle is an
annual insect pest to be concerned about. This small insect can cause
There are two reasons cucumber beetles spell trouble for certain vegetable
plants. The first way is by direct consumption of leavesa visible
condition that is especially a problem when plants are small. Even more
damaging, however, is the fact cucumber beetles can carry bacterial wilt
disease, a serious problem of cucumber, muskmelon, and watermelon. Infected
plants suddenly wilt and die after the beetles have been feeding.
There are two types of cucumber beetles, the spotted and the striped.
Both are small beetles, less than 1/4-inch long and yellow-green in color.
The striped cucumber beetle is most common in our area, and has three
black stripes down its back. (The spotted has 12 black spots). Flip it
over and the rear portion of the underside should be black. If it's yellow,
it's the western corn rootworm beetle, not considered a serious pest of
cucumbers or melons.
Cucumber beetles start feeding early in the season, often eating plant
leaves emerging from the soil. If the beetle is carrying bacterial wilt
disease, the plant becomes infected. Symptoms may not show until later
into the season, when the vines wilt and die.
As plantings are made in the garden, watch for the cucumber beetle. Control
it by applying either carbaryl (Sevin) or rotenone. Reapply
at about weekly intervals if beetles are still present.
Once the plants start to bloom, apply late in the day and keep the insecticide
off the blooms to avoid contact with bees and other pollinating insects.
Another early season control option is to use a polyester row cover.
Put the cover over cucumbers and melons, making sure to seal the edges
into the soil. Look carefully around the plants before doing this, however,
to assure there are not any cucumber beetles present that could be trapped
under the cover! Once the plants start to bloom, the cover needs to be
removed so pollinating insects can get to the flowers.