Smart planning and planting should repel squash vine borers

Backyard Q&A

In The Garden

July 25, 2004|By Jon Traunfeld & Ellen Nibali | Jon Traunfeld & Ellen Nibali,Special to the Sun

It's our first major garden, and we planted all cucurbits (pumpkins, gourds, butternut, acorn and spaghetti squash). Then we had a major squash vine borer invasion. We rescued many vines by making a vertical slice in the stem, killing the borer, and then mounding dirt over the wound. Is there any other organic way to combat the borer?

To reduce the number of squash vine borers for next season, clean up all plant debris at season's end. Till your soil in the fall, and again in spring, to kill overwintering pupae. Protect young plants from egg-laying in spring with a floating row cover (a light gauzy material that excludes pests). When blooming begins, remove the cover so pollination can take place. In addition to the surgical removal you performed this year, some or-ganic gardeners inject Bt into squash stems with a syringe or spray lower stems with rotenone. Others band their stems with aluminum foil to prevent egg-laying. Early (late April) and late (mid-June to mid-July) plant-ings will often suffer less injury.

You may want to diversify your vegetables more next year. Planting a large area with one family of plants creates a monoculture that encourages pest problems.

Some new plants appeared in my flower and shrub beds last year. They made tidy low circles of scalloped leaves. This spring they grew tall stalks with little white flowers that were OK. But now they have seed stalks with lots of pods getting ready to pop. There's already a patch of this stuff. Pull or keep?

Your volunteer plants are probably garlic mustard, a highly invasive non-native plant. It was imported centuries ago, but unfortunately has now taken hold in our parks and is overwhelming the native plants (which our wildlife need). Garlic mustard is a biennial (two-year life cycle), so as long as you destroy all the seeds, you can get rid of this invader before it takes over your landscape -- and your neighborhood.

We have a serious infestation of millipedes. I thought they liked moist areas and decaying matter, so I don't understand why they leave outside to come into the house. We regraded around our house two years ago and got rid of water problems inside but not the millipedes. We try to live our lives without pesticides.

Dark, shiny and short-legged, with a habit of curling into a ball, millipedes feed on decaying organic matter. Eliminate their habitat by keeping mulch at least 6 inches away from house foundations. Thick ground covers such as ivy also provide a good environment for millipedes. Locate woodpiles or compost piles far from the home. Double-check the air conditioning unit, water heater, and uninsulated pipes for signs of leaks or excess condensation.

In especially wet weather, even millipedes have too much of a good thing and retreat inside. Until weather becomes drier, we recommend vacuuming up the millipedes.

Checklist

1. When vigorous tomato vines grow over the tops of stakes or cages, they can be headed back with loping shears to keep them in bounds. This will not diminish your harvest.

2. Add water to your backyard pond if the water level drops.

Jon Traunfeld, regional specialist, and Ellen Nibali, horticulture consultant, work at the University of Maryland Cooperative Extension's Home and Garden Information Center. The center offers Maryland residents free gardening information and answers to plant and pest questions. Call its hot line at 800-342-2507 (Monday through Friday, 8 a.m.-1 p.m.) or e-mail questions to www.hgic.umd.edu. (You can also download or order publications and diagnose plant problems online.)

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