Organic Measures for Controlling Squash Bugs

The ever pesky squash bug is common throughout North America and can literally take over a garden if proper controls are not implemented. The bugs primarily prefer to attack squash and pumpkins but have an appetite for other vine crops such as melons, gourds and cucumbers.

The adult squash bug has a flattened armor-like appearance and measures about 5/8 of an inch long and 1/3 of an inch wide. Usually dark gray to dark brown in color, the edges of their abdomens protrude beyond their wings and typically have alternating orange and brown stripes.

Mouthparts of these plant "vampires" allow for piercing and sucking the sap out of leaves causing yellow spots that eventually turn brown. The reduction of plant fluids disrupts the flow of vital nutrients to the plant and contributes to wilting. Young plants are especially susceptible from damage and may die from the attacks. Larger, more vigorous plants, though more tolerant to damage may also die from a severe infestation.

Overwintering adults fly to squash plants to feed and mate in the spring. Female squash bugs lay individual eggs in small clusters of about 12 to 20 on the undersides of leaves in a distinctive "V" pattern. Females will continue to lay eggs through mid-summer. Eggs hatch in about 10 days and the nymphs go through a five stage transformation process until they eventually become adults. One generation develops each year although it is possible to have a second generation depending upon the timing of the first freeze. The nymphs die when temperatures drop to freezing and adults crawl or fly to shelter for overwintering.

The most critical time to control squash bugs is when the plants are seedlings and when they are flowering. Healthy, vigorous plants will help limit destructive blows and result in a better survival rate. Synthetic insecticide use should be avoided if at all possible both for the health benefits relating to consumption of the fruit as well as the fact that the poison may indiscriminately kill beneficial insects such as bees and ladybugs.

Sabadilla dust has been successfully used to control squash bugs. It is derived from the seeds of a lily indigenous to Central and South America. Sabadilla acts as a contact and stomach poison. It should only be used in the evening to minimize damage to honeybees. It biodegrades rapidly in sunlight and is considered to be one of the least toxic of botanical insecticides. Since sabadilla dust is derived from plant material it is permitted for organic production. At times it is difficult to find. Check with your local garden center for availability.

The home gardener will find hand picking and trapping of squash bugs to be effective in preventing a major infestation. If incorporated as part of the daily morning gardening ritual, this method can be an effective and totally organic means of maintaining security against these voracious insects. The bugs tend to congregate together during the night and are easy to pick and place in soapy water. Gardeners with raised beds will find many of these pests lounging around on the wood surrounding the garden in the early morning. Catch them while they are somewhat docile. They are a challenge to catch as the day warms up and they become more active. They don't bite but they can give off an offensive odor.