Aphids & Whiteflies on Squash Plants 

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We have an infestation of aphids and whiteflies on our squash plants. The whiteflies came after we had sprayed different chemicals hoping to get rid of the aphids, spider mites and then we’ve been to try to kill the squash bore worms too. We’ve been using NEEM oil and Thermacide (injected in stem), we’ve also put Sevin dust on them and Sevin liquid spray at different times.

At first our plants were thriving and then they got the squash bore worms. Once we did a treatment of NEEM Oil one day and Thermacide the next then some Sevin dust I think a week later, I looked at the garden one day and the plants were just covered in the white flies and aphids. We’d like to save them

The following is a listing that appears in our Parker County Master Gardener handbook that was published this year. You are fighting two common insects in many crops. Be careful what you spray because sometimes the spray you use can kill beneficial bugs that are helping you fight the bad bugs.

Aphids are tiny pear shaped insects that can be many colors attach themselves to underside of plant leaves and suck the sap. They cause a sticky residue on and beneath leaves and on tender growth of plants such as crape myrtles, daylilies, oaks, roses and pecans, (aphids may occur on pecans from late spring until early fall, leave aphids alone or use soapy water blast to wash them off pecan trees). If left untreated, a black sooty mold will grow in the honeydew coating (a sweet sticky substance secreted by various insects).

Whiteflies are lost active in warm parts of the day. They congregate on underside of leaf and suck sap from leaves. They resemble tiny winged moths. Leaves often will be covered with black sooty mold, honeydew (a secretion from bugs). Note: Check container plants you intend to bring indoors this winter for pests. Check drain holes and around pots for pests.


1. Use a hard blast of water from the garden hose.
2. Spray with mild solution of soapy water.
3. Use natural predators such as lady beetles etc. Use fly larvae predators. (Aphidoletes aphidimyza), or common green lacewing (Chrysoperla carnea).
4. Use citrus oil products, insecticidal soap or ultra fine horticultural oil.
Tip: On food products don’t use 5 or 6.
5. Can use Sabadilla dust or WP (wettable powder) dust (apply to wet plants).
6. Can apply acephate, malathion, systemic insecticide; be sure to follow label directions carefully.

1. Usually winter does the best possible job. Discard all old stems and foliage after the first hard freeze.
2. Predatory wasps (Encarsia Formosa), Common green lacewings (Chrysoperla carnea), Lady beetle (Delphastus pusillus) can be used.
3. Treat in environmentally friendly manner. Mix dish detergent in water and pour mixture into mister bottle. Spray infested plants vigorously. Repeat this process every 5 days until bugs have disappeared. When sooty mold covers leaves, use damp cloth and gently wipe mold away.
4. Yellow pest strips or bug sticks that are hung in area of pests.
5. Ultra-fine horticultural oil.
Tip: On food products do not go past 5
6. Use safer spray that is labeled for houseplants (such as Safer Soap).