Sylvia Squash Bug — otherwise known as Anasa tristis by her latin ancestry — is a grayish-brown garden night stalker. Quite the fashionable Squash Bug, she sports a drop-shaped wing pad at the end of her 1/2-inch body displaying brown and orange markings along her abdomen and underside.  As cute as she may think, Sylvia Squash Bug is one of the most notorious phantom garden pests who hail from a long line of plant-boring ancestors.  Often Sylvia Squash Bug is mistaken for a Stink Bug (with similar physical traits, and a foul odor when squished). Her family of squash bugs is a close relative to the cockroach, although both bug families are squished by the idea when the topic is brought up at any master gardener party.

A boring phantom connoisseur extraordinaire, Sylvia Squash Bug moves silently and deliberately through the shadows of the night in search of fulfilling her desires. Unlike the Phantom of the Opera musical, her longings are not focused on some unrequited love. This squash bug’s sights are set on my winter squash, summer squash, pumpkins, zucchini, cucumbers and melons.  If she is left unattended, Sylvia Squash Bug births 25-40 oval eggs — on average 1/16th of an inch — on the underside of the leaves. These eggs range in color from reddish to bronze to yellowish-orange.  She is prolific after hibernating in the soil over winter and laying her first eggs in early spring after the first freeze. Sylvia Squash Bug can lay several sets of eggs during the growing season.

Squish this Squash Bug’s appetite:

1. The first signs of squash bug damage are seen on the leaves. Yellow spots initially appear and then change to brown. If Sylvia Squash Bug and her phantom brood of nymphs heavily feed on leaves, the entire leaf wilts and becomes crispy and dry. The leaves turn black. If the squash bugs bored into the stem, as well, it will collapse and most likely kill the plant. Weekly vigilance is needed to stay ahead of this pest.

2. Kill squash bugs and their nymphs (or the eggs before they hatch) by picking them off the leaves and crushing or drowning them in a container of water (mixed with some detergent). Check the underside of leaves for eggs.

3. You can try row covers — or wrap aluminum foil or nylon stockings around the base of the plant stem.

4. Crop rotation with plants that are not susceptible to squash bugs is an initial defense. Planting a little later in the season — especially squash and pumpkins — after the majority of squash bugs hatched (and perished) sometimes can help get ahead of a potential squash bug infestation.

5. Selecting pest/disease resistant plant varieties for the following year — if there was a problem in the current growing season — will help to nearly eliminate squash bugs as a reoccurring garden challenge; for example, Zuke Squash can be an option that squash bugs seem to attack the least.

6. Companion planting is not a sure method of eliminating or decreasing the likelihood of our garden boring phantoms of the night returning. Some master gardeners, however, have had success with: radish, mint, catnip, marigolds, bee balm and nasturtium.

7. Keep garden beds clear of debris and properly feed plants with regular watering to maintain a healthy environment to grow strong plants. In fall, pull all plant roots, till and turn soil many times.

8. Insecticidal soaps (commercial or homemade) can be helpful. Spinosad is another organic remedy to consider.


Bill Dochnahl, of the OSU Extension Master Gardener Program, has a degree in public    administration and urban development. To contact Dochnahl with questions, email or call 278-5403.

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