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Past Articles Library | Organic Pest Control | Control Squash Bug

NATURAL SQUASH BUG CONTROL
(Anasa tristis)

Squash bugs and their nymphs suck plant sap and can cause vines to wilt. They are very common, and while they primarily attack squash and pumpkins, they also attack cucumbers, gourds, and melons.

DESCRIPTION

Adults are oval, dark gray to dark brown-black, and 5/8 inch (15 mm) long. They have a flattened abdomen, and the edges of their abdomens protrude beyond their wings and typically have alternating orange and brown stripes. Young nymphs are pale green, and they develop a darker, reddish thorax and abdomen as they mature. Older nymphs are covered with grainy gray powder. Eggs are shiny yellow to brick red and elliptical in shape.

LIFE CYCLE

Adult squash bugs overwinter in sheltered places such as under garden litter, rocks, vines, or boards. When adults emerge in the spring, they fly to growing cucurbit plants to feed and mate. Females lay eggs in small clusters on stems, but normally on the undersides of leaves, especially between the veins where they form a V. Eggs hatch in 1 to 2 weeks, and nymphs take 4 to 6 weeks to develop, molting five times before becoming adults. Both adults and nymphs are secretive and quickly scurry for cover when disturbed. In the fall, especially after the vines have died, the adults, and older nymphs often congregate on squash fruits. The nymphs die when the temperatures drop to freezing, while the adults gradually fly or crawl to sheltered places to overwinter. Squash bugs have one generation per year.

PLANTS MOST AFFECTED

Squash, pumpkin, cucumber, gourd, and melon.

DAMAGE

Both adult and nymph squash bugs have piercing-sucking mouthparts that they use to suck the sap out of leaves, causing the leaves and shoots to blacken and die back. Their feeding causes yellow spots that eventually turn brown, and their feeding disrupts the flow of water and nutrients, which can cause wilting, and may be mistaken for a wilt disease. Unlike cucumber beetles, however, squash bugs do not transmit diseases, and while young plants are much more susceptible to damage and may die from extensive feeding, larger, more vigorous plants are more tolerant of feeding damage, although they can also be injured or killed if they severely attacked.

NATURAL SQUASH BUG CONTROL

Prevention:

1. The most important times to control squash bugs are when the plants are young seedlings and when they are flowering. Early detection of nymphs is important, as adult squash bugs are difficult to find in order to kill.

2. Plant resistant squash cultivars such as 'Early Prolific Straightneck', 'Early Summer Crookneck', 'Royal Acorn', and 'Table Queen'.

3. Support vines off the ground on trellises if practical.

4. Cover young plants with floating row covers. See more information at the end of this article.

5. Maintain healthy, vigorous plants through proper fertilization and watering to help limit squash bug damage.

6. Remove plant debris around the garden during the growing season to reduce the potential harborages where squash bugs may hide. Clean up cucurbits and other plant matter around the garden in the fall to reduce the number of overwintering sites.

Control:

1. Hand pick bugs at all stages from undersides of leaves and put them in a bucket of soapy water. This can be challenging because squash bugs hide under leaves and move quickly when disturbed.

2. Crush eggs that are attached to the undersides and stems of leaves.

3. Trap squash bugs by laying out boards or pieces of newspaper. Squash bugs will congregate under the boards at night, and then can be collected and destroyed in the morning.

Use Floating Row Covers

Save yourself, and your plants tons of trouble, get some floating row covers today. They're fast to put up, inexpensive, and they save you so much time, effort and labor!


More Floating Row Cover Information


Use Super-Light Insect Barrier

This lightweight row cover gives your plants remarkable protection from insects all year long. The see-through fabric allows 95% of the sunlight in, but with little heat buildup, which means no harm to your heat-sensitive plants!

More Super-Light Insect Barrier Information