Cucumber beetles do more than eat your plants

When we inspect our gardens we might notice small striped

beetles on our cucumber, squash and melon plants. Sometimes they

are spotted. These little critters are called cucumber beetles

and they are a double threat. Sure, they chew holes in the

leaves, but they do much more than that.

Bacteria overwinter in the digestive systems of cucumber

beetles. The beetles deposit them on the leaves and the bacteria

multiply and infect the plants. Leaves and stems usually wilt

and dry out. Sometimes this can happen suddenly, much like what

happens with squash vine borer.

At first the wilting is much worse during the middle of the

day and plants somewhat recover at night. Eventually the entire

vine will die. Some plants can show partial resistance. Plants

branch and bloom more and they don’t grow as vigorously.

Cucumber beetles themselves don’t cause the disease and it

is possible, though unlikely, that the beetles might not be

infected with the bacteria. Controlling the beetles is the only

way we can control bacterial wilt.

Bacteria grow so fast that trying to kill them with

antibiotics would be economically futile. We would have to apply

a bactericide frequently to stay ahead of the rapid reproduction

of the bacteria and it would be futile. Bacterial diseases are

usually difficult to control in plants.

However, chemical treatment options are more promising than

they are for squash vine borer, but one factor remains constant.

Plants must be treated at the first sign of adult beetles,

perhaps before.

Since the culprit that spreads this disease is a chewing

insect, systemic chemicals are not necessary. However, using

Idamicloprid at planting can be beneficial. Pyrethrums or Sevin

both are effective once plants start to spread rapidly and

beetles become plentiful. These insecticides can be purchased at

most garden centers.

If you wish to shy away from pesticides other methods can

be effective. The first and most important is to examine your

plants frequently. If your garden is small you might be able to

control the beetle population manually. Unfortunately, they can

fly.

As with squash vine borer you can use netting to keep

beetles out. If you notice symptoms of the disease you should

remove those branches to preserve the integrity of the rest of

the plant. Simply removing infected tissue is not enough. It

must be removed from the area and destroyed.

Crop rotation is also important. Plants in the cucumber

family should not be planted in the same place every year. These

beetles overwinter in the soil. Therefore the bacteria will also

be present there. It’s best not to plant cucurbits in the same

spot for at least three years. An exception might be watermelon

as they are far less susceptible than other cucurbits.

Also, it’s a good idea not to plant cucurbits next to corn.

Immature spotted cucumber beetles often feed on corn. This

includes both sweet and field corn.

Gardening is a fun pastime, but obstacles to success are

numerous. Still, the satisfaction of harvesting something you

grew yourself makes it worthwhile.