Insecticidal Soap & Squash Bugs

Insecticidal Soap & Squash Bugs

Squash bugs, among the greatest banes of home vegetable gardens, like feasting on yearly cucurbit plants developed in U.S. Department of Agriculture plant hardiness zones 2 through 11. They pose a severe danger to pumpkins (Cucurbita pepo var. Pepo) as well as crookneck (Cucurbita pepo var. torticollia) and straightneck (Cucurbita pepo var. recticollis) yellow squash varieties. Squash bugs can quickly damage or even kill garden plants, but using insecticidal soap sprays can help you get rid of squash bugs and protect your veggie crop.

Regarding Squash Bugs

Squash bugs (Anasa tristis) hit only over 1/2-inch long and approximately 1/3-inch wide and possess yellowish-brown to black bodies that look similar to stink bugs. Adult squash bugs overwinter beneath rocks, fallen leaves, compost heaps or other garden debris, emerging the following spring to eat and mate. After mating, the females lay groups of rust- or bronze-colored eggs under the leaves or on the stems of young cucurbit plants. Tiny, light green nymphs emerge five to ten days later. Adult squash bugs typically feed on the large stems of cucurbit plants, while the nymphs prefer eating the leaves. Both utilize their piercing-sucking mouthparts to beverage plant juices, which disrupts the flow of water and nutrients and causes the affected plant tissue to come up with spots or speckles before turning yellow or brown. Severe infestations cause the leaf to dry out, suddenly wilt and develop fragile, black tissue in feeding sites. Small garden plants can die, while larger plants may eliminate some of their runners.

Regarding Insecticidal Soaps

Gardeners have used insecticidal soap goods as all-purpose pesticides for more than 200 decades. The active ingredient, potassium salt of fatty acids, kills soft-bodied pest insects, like squash bugs, by crushing their outer protective coatings, causing them to dehydrate and die. Insecticidal soap alternatives control small nymphs far more effectively than adult nymphs and adult bugs, however, so start checking and treating infested cucurbit plants early in the growing season. Insecticidal soaps are non toxic to people, animals, honeybees and most beneficial predatory insects. Soap sprays are safe enough to apply to cucurbits up until the time of harvest. Insecticidal soap often burns plant leaf, however, because the acid can strip the waxy, protective coating off plant leaves. The Colorado State University Extension recommends spraying soap solution on a small, unnoticeable section of leaf and waiting one to two days prior to checking for injury. If no burning occurs, go ahead and spray your entire plant.

Using Insecticidal Soaps

When using an insecticidal soap product, follow the manufacturer’s instructions and safety precautions printed on the label. Horticulturists from the University of California’s Statewide IPM suggest treating plants with a spray containing a 1 to 2 percent solution of insecticidal soap. To achieve this percentage, mixture 2-1/2 to 5 tablespoons of soap concentrate for each 1 gallon of water. Utilize a handheld garden sprayer to thoroughly moisten all plant leaf, like the undersides of leaves. Insecticidal soaps only kill squash bugs that come into direct contact with the wet spray, therefore complete coverage is essential. Start treating cucurbit plants with the soap solution as soon as you place the pests in spring up, and repeat applications every three days for 2 consecutive weeks. Apply soap sprays only on calm days when no rain is anticipated for at least 24 hours. Reapply if rain will not occur in that time period. Avoid spraying when the sun is shining directly on the plants or you risk burning the leaf.

Staying Safe

Although insecticidal soaps are environmentally friendly and have low toxicity to people and animals, the sprays can still cause eye or skin irritation on contact. Reduce the chance of exposure from donning goggles, waterproof gloves, shoes with socks, a face mask, long sleeves and long trousers before mixing or spraying soap alternatives. Keep pets and family members out of the treatment area until the spray completely dries.

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