Squash Bugs
My first encounter with squash bugs was when I was tending my neighbor’s gorgeous garden while she was away. I diligently checked her plants for potential problems most days as I would my own. One day everything was vigorous and healthy, but when I next checked her squash and cucumbers were well on their way to being decimated and covered with the prehistoric looking creature. And since they enter our gardens as adults, I immediately checked my garden and found several there already.
When adult squash bugs come out from their winter shelter in spring, as soon as the vines start to run, they quickly fly to running cucurbit plants to feed heavily and mate. Early females may lay eggs quickly and the eggs may produce nymphs by the time larger numbers of adults are even detected. The adults tend to congregate on the underside of the leaves so a good deal of damage may occur before you even notice adults moving about on the leaves. Both the adults and the nymphs will feed quickly.
It is important, which I was not aware of while tending my neighbor’s garden, to check the underside of leaves daily if not twice a day. Things happen quickly with squash bugs. They suck sap from the leaves, but their saliva also contains plant toxins which causes the telltale sign of blackened crisp leaves if they have been allowed to continue undisturbed. Early or very late in the day are the best times to inspect your cucurbits, especially of course squash and pumpkin plants. If young plants are infested early in spring damage can be fatal. If adults appear in the garden later when the plants are more mature, large strong plants are much more tolerant of the damage caused by feeding.
Identifying Squash Bugs
Squash bugs are fairly easy to identify but they do look very similar to a stink bug, which you will not commonly find in your gardens. The squash bug is brown or gray brown and one half the three quarter inches long with six legs and long antennae. They have a hard shield like shell and two wings. Their sucking mouth parts are perfectly suited to sucking the sap from leaves.
Beginning in early June, the eggs are laid through mid summer in clusters on the underside of leaves. Females will lay several clusters, up to 250 eggs. Eggs are only 1/16th of an inch long and bronze or yellow brown in color. The nymphs hatch in 7 to 10 days and initially are light green with black heads and legs. As they grow the turn gray to brown gray. If left to proliferate, by fall you can see both nymphs and adults congregated on the fruits to feed. This is your last opportunity to destroy any squash bugs and nymphs still in your garden.
By end of season any nymphs are killed by freezing temperatures, but the adults take shelter under debris, or rocks, even in sheds, for the winter.
Controlling Squash Bugs
Once you have detected squash bugs, whether adults, eggs or nymphs, there are many ideas for keeping them under control. The sooner you detect their presence, the easier it will be to kill nymphs and destroy eggs. Adults are tough shelled and more difficult to kill.
Drop adults and nymphs into a pail of soapy water. This will be more difficult/time consuming in large numbers.
Eggs found under leaves can be removed and crushed.
Eggs in large numbers can be lifted from leaves with duct tape and then crushed in large numbers.
Eggs can alternately be pushed off the leaves onto the ground. They cannot get back to the plant but they may still hatch. Often they will die or be eaten.
Adults will congregate under newspaper or boards overnight. Collect them from these traps and destroy them early in the morning. Squash bugs are stinky when you crush them, so you may prefer to drop them into a soapy bucket if that is manageable.
Keep gardens clear of plant debris where the adults like to hide.
Avoid mulching your garden with straw or other mulching material.
Remove all cucurbits plant remains in fall. If there are any live bugs or eggs, close the plant debris tightly in plastic bags. Place in the sun to kill everything. Never put in your compost pile.
Search out resistant varieties of cucurbits, especially squash and pumpkins.
Cover vining crops with floating row cover until they flower to keep the squash bugs out until the plants are more matured. Once they begin to flower you must remove the row covers to allow pollination.
If squash bugs have been a problem for you, try Butternut, Royal Acorn or Sweet Cheese squash varieties. They are more resistant to the squash bug. Plants most commonly affected by the squash bug are squash and pumpkins, zucchini, and cucumbers, sometimes melons.