And so it begins… I checked some of my squash plants the other day and there they were as happy as can be. Two squash bugs enjoying their afternoon on the leaf of a buttercup squash. Upon further inspection, I found a cluster of their reddish-brown eggs nicely stacked on a stem. This is the time gardeners need to stay vigilant about checking their cucurbits (squash, melons, pumpkins, cucumbers, gourds) for summer pests. Here are the three main headliners looking for a cucurbit near you.
Squash bugs: These will attack all members of the Cucurbitaceae family but seem to prefer pumpkins and squash. They feed on the foliage by sucking out the sap but can also feed on the fruit. Severe infestation can cause leaves to wilt, turn brown and die. This makes them more of a concern when plants are seedlings and when they are flowering.
The adult is unremarkable in appearance. It has a flat, dark grayish body about 5/8 of an inch long and 1/3 as wide. It can be easily confused with a stinkbug. Adult squash bugs are difficult to kill. Control of adults and any egg clusters found on the underside of leaves or on stems is usually done by picking them off by hand. As squash bugs like to gather under debris, you can also lure the adults by placing a board or heavy cardboard under the plant. Check in the morning and remove those found hiding. Immature squash bugs (nymphs) can be controlled with insecticidal soap or spray. Read the label to ensure it works on the intended pest and can be used on your crop. As with any insecticide, please follow the directions carefully.
Cucumber beetle: A colorful cucurbit pest. The spotted cucumber beetle has a yellowish-green body with prominent black spots. The striped cucumber beetle has yellow and black striping. They appear in the spring and can be present throughout the growing season. Cucumber beetles feed on the leaves and stems of cucurbits and can kill or greatly curtail the growth of young plants. Adults will also eat the blossoms and fruit.
As they forage, cucumber beetles can spread bacterial wilt. The disease overwinters in the adult’s body. Management of the beetle is the best way to prevent bacterial wilt. There is no effective treatment once a plant is infected with it. Keep in mind that wilt can sometimes be mistaken for other cucurbit problems such as squash bugs or lack of moisture.
A non-chemical control for cucumber beetles is to use floating row covers. These covers create an effective barrier between the beetles and plants. Just remember to take the covers off when plants are in bloom to allow for pollination. If your crop is small enough, you can remove the beetles by hand. This can be time-consuming, but it works, if you don’t mind touching bugs. Good cultural practices such as eliminating weeds in and around the garden can help deter them as well. Insecticides are also available.
Squash vine borer: The adult borer is a wasp-like moth with an orange-colored abdomen dotted with black spots. It typically appears in late June or early July to lay its eggs primarily on squash and pumpkin plants. The eggs hatch in about a week. The larvae then bore into the plant stem to feed. Damage to the stem by the tunneling larvae blocks water flow to the rest of the plant causing it to wilt and eventually die.
Now is the time to monitor for the presence of the adult borer. The use of floating row covers will prevent this female pest from landing and laying eggs. Chemical control includes applying an insecticide to the stem of the plants at the end of June or early July or when an adult borer is seen.
A note about bees and insecticide use. We all know how important bees and other pollinating insects are. Try not to use insecticides that are toxic to bees and avoid application when garden crops are in bloom. Apply insecticides later in the evening to avoid spraying while bees are actively foraging. Keep in mind that when it’s hot, bees can be active earlier in the morning and later in the evening.
