Dirt on Gardening

When it comes to bugs in my garden, I spend time researching what kind of bugs they are. My research usually involves a dead bug in one hand and a book about bugs in the other hand. I am not an entomologist. However, as a gardener of a few years there are certain bugs that I can “count” on each year in the garden.

Squash beetles are a bug that will eventually always find my garden — especially my squash plants. Squash bugs are considered to be “true bugs” because they overwinter in the soil and emerge when warm weather occurs.

An adult squash bug is almost an inch long and dark gray or black in color. The bug has two antennae at the top of its head and brown and orange stripes on its abdomen. Squash bugs have a slightly hard shell and can emit an odor when crushed. The odor sometime causes them to be confused with stink bugs.

The really bad news for gardeners is that if the weather conditions are right, squash bugs can produce a partial second generation in one year. Gardeners must be vigilant against them. It’s not uncommon to pull the leaves of a squash plant back to see two adult squash beetles mating with baby beetles crawling around and bright red eggs attached to a leaf nearby.

Squash beetles attach their eggs to the underside of plant leaves. The eggs are the size of a pin head and are brown to red in color. There may be anywhere from five or six eggs to over a dozen. The eggs darken in color as they age.

Nymphs (baby squash bugs) don’t take very long to reach adult stage, but when they are first hatched, they have a red head, green abdomen and black legs. Their body and legs change color as they age.

Squash beetles prefer members of the Cucurbita family, so they can be found on pumpkins, cucumbers and gourds, but they prefer squash. They suck on the vines of squash plants causing the plants to wilt and ultimately die.

There are some natural enemies to the squash bug — a parasitic wasp, a tachinid fly and the pink-spotted lady beetle. Simply picking the bugs off and killing them and scraping the eggs off the leaves is also very effective for controlling squash bugs.

A liquid pesticide containing pyrethrin is also effective when handpicking doesn’t provide enough control. A liquid must be used so the beetles will ingest it while sucking on the squash vine. Pesticide controls also work best on nymphs than fully developed squash beetles.

Questions or comments related to gardening? Contact Joleen at missourigardener@hotmail.com

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