Along with tomatoes and peppers, squash is one of the most popular vegetables grown by backyard and market gardeners. Squash are divided into two categories: summer and winter, and both are subdivided into multiple species.  The summer varieties we’re most familiar with are Yellow (straight and crooked neck), Scallop, and Dark Green Zucchini. Popular winter varieties include; Spaghetti, Acorn, Butternut, and several kinds of pumpkin. There are, of course, many others; each with its own set of characteristics and fans.

One thing all squash varieties have in common are their beautiful flowers. The female flowers are delicate and feminine, while the males are big, bold, and eye catching. Squash flowers are arguably as aesthetically pleasing as any ornamental flowering plant and they positively light up a backyard or container garden on late spring and early summer mornings.

All squash plants also share a pair of enemies; the extremely destructive Squash Vine Borer and the ubiquitous Squash Bug. They are labeled, ‘garden pests’, but can be more like a plague, destroying an entire crop in a very short period of time.  Nearly every gardener dreads their inevitable appearance and the ensuing fight for supremacy their annual appearance heralds.

Let’s take a minute and look at these insects and then discuss an effective plan for naturally and organically defeating them.


Squash Bug

Adult Squash Bugs are easily recognized by their wedge shaped bodies, resembling their cousins, the Stink Bug. Squash Bugs grow up to half an inch and lay many dozens of eggs. The eggs look like little copper clusters on the tops of squash leaves. Both the adult and juvenile bugs feed on the plant sap through the leaves and stems. While the juveniles stay on the leaves, the adults work their way down the stalk to spend the night at the base of the plant or under nearby sticks, boards or rocks.

The adults who laid the eggs will die off during the summer, while their offspring will survive the winter by burrowing underground only to reemerge in the spring and begin the cycle all over again. It is not at all unusual to find them as the soil beneath the squash patch is worked for a new spring garden.

They can be difficult to manage, and if not controlled, can spread to melons and cucumbers after killing off the squash crop. 


Squash Vine Borer

The squash vine borer is a stealth killer. The damage is often done and irreparable before the gardener even knows she’s/he’s been attacked. It can be extremely frustrating.

The borer is a moth, but it looks kind of like a fly and wasp had a baby.  They are only active for two or three weeks in the spring, but they get a lot done in that time.

It’s not the actual moth, but the larvae (caterpillar) that does all the damage.  The moth lays its eggs on the stem of the plant. Once the larvae hatch, they work their way to the base of the squash and, as the name suggests, bore (eat) their way into the stalk and kill the plant from the inside out. 

The squash plants often look healthy one day and are dead the next. Since multiple larvae can attack a single plant, destruction can be very fast. The only telltale sign is the appearance of brown, sticky pulp at the base of the plant and along the stems where the Borers have been active.

Eager to protect their squash crop, many gardeners immediately reach for the ‘chemical weapons’ readily available at any big box garden center, but that’s not an option for those of us who are trying to garden organically and naturally. The good news is, there are organic and natural options that can eliminate the need for going ‘nuclear’.

The first option is to get your plants out early in order to get ahead of the Borers. Once the plants begin to develop female flowers, they tend to be able to fight off attacks. Either that or the mature plants don’t taste so good.

Here in North Georgia, where I live, the Borer moths are active from the second week of May through the end of the month.  You should check with your local extension office to discover when they are active in your area.

If you can start your plants early, indoors, and set them outside as soon as the threat of frost is past, you can often get ahead of Borers.

Another effective option is to use row covers and cover your squash and zucchini until they begin to flower. Row covers allow in light and water, but keep the bugs off. 

If you are fortunate enough to live in a part of the country that has two growing seasons for squash, you might want to wait until the second season, which will eliminate the threat of Borers altogether.

One option that’s effective for both Squash Bugs and Borers is to dust the base of the plant weekly with food grade Diatomaceous Earth. DE is a natural substance formed from the shells of the tiny diatoms that died long ago.  There are enormous deposits of DE and a little goes a long way.

DE kills most soft bodied pests and parasites and is totally edible for humans and pets.  Many farmers and pet owners feed it to their livestock and household pets to control internal parasites naturally.  If used regularly, it is highly effective.

At the risk of being too graphic, when the Borer or Bug crawls over the Diatomaceous Earth, the sharp edges of the DE cut it up and kill it. Since Borers enter through the base of the plant, and adult Squash Bugs sleep there at night, regular dusting will be a valuable tool.

It is also fine to dust leaves, especially the underside of leave where juvenile Squash Bugs like to feed.  Never dust the flowers though. DE, like any pesticide, cannot distinguish between good bugs and bad. Since bees and butterflies land on the flowers in order to effect pollination, dusting the petals would kill these beneficial insects as well.

An attractive deterrent to Squash Bugs is to plant Nasturtium and Marigolds among your squash plants.  I have used Nasturtium effectively many times. The flowers are pretty and are also edible.

It seems that many garden pests hate Marigolds.  I’m ok with that. I don’t like pests and I think Marigolds are gorgeous. So I plant dozens of them in my garden.

Squash Bug eggs are difficult to miss. The bronze or copper colored clusters of eggs are usually on larger leaves and can be on either the top or under side of the leaf.  To get rid of them, simple take your thumb nail, a knife, or something similar, and scrape them off. It’s a fairly easy process.

One more useful method in battling Squash Bugs is to lay pieces of wood or even cardboard at, or very near, the base of the plant. The bugs like to sleep under the cover of the wood. Go out early in the morning, pick up the wood and knock the bugs off of the wood into a bowl or bucket of soapy water.

I skip the water and feed them to my chickens and turkeys. Free range poultry find the little bugs delightful.  Don’t let the chickens into the garden, though, because they’ll eat your squash; not to mention, your melons, tomatoes, beans, strawberries and anything else that’s growing.

A final weapon in your arsenal is to fill a spray bottle with water and add a squeeze of dish soap to the water. Shake it well and spray the bugs directly. They will start dropping fairly quickly. Just pick them up and throw them away. This is a little more time consuming, but saving your zucchini is worth a few extra minutes.

Everyone, except those gardening in some far northern States is going to battle Squash Bugs and Squash Vine Borers. They are the very definition of ‘pests’, but you need not panic. A few simple tactics will keep your squash plants happy and your crop prolific.