Swift action needed to avert the spread of oak disease

Backyard Q&A

April 03, 2005|By Jon Traunfeld and Ellen Nibali | Jon Traunfeld and Ellen Nibali,Special to the Sun

Is there any cure for Sudden Oak Death? Is there a preventative?

There is no cure or preventative for Sudden Oak Death. That's why it's so critical to locate the hundreds of infected plants that accidentally got shipped into Maryland before Sudden Oak Death destroys our landscapes and forests. Sudden Oak Death is able to infect more than 70 species (and the number is still rising), including blueberries, redwood, Douglas fir, viburnum, andromeda, mountain laurel, azalea and rhododendron.

Now, with weather warming up, the disease spores will become active and spread. Before this happens, Maryland needs to locate lilacs, rhododendrons, camellias and azaleas purchased in 2003 and 2004 that may be infected. Infected plants will display unusual symptoms -- especially leaf spotting.

If you suspect that you own any one of these plants, please contact us for information on how to get the plant(s) tested for free. Never move suspected plants, even to the landfill, because of the danger of spreading spores. For more information, click on Sudden Oak Death on our Web site home page.

I'm looking for trees in 5- to 7-gallon pots. I want to plant 18-24 trees along my driveway, but I can't locate any in that size that I can afford.

When you're planting a considerable number of trees, cost really adds up. Planting smaller trees can be more cost-effective, because smaller trees acclimate themselves to site conditions faster than larger trees. They catch up to and even surpass large-size trees in a fairly short period. For example, after five or six years, a healthy young tree planted with a trunk of 2 inches or less will be bigger than a tree planted with a 6- to 7-inch trunk.

What is IPM? I've seen this term in gardening articles lately and also in your publications.

IPM, or Integrated Pest Management, is the up-to-date approach that prevents plant and pest problems or manages pests at acceptable levels, using biological, physical and cultural techniques and -- as a last resort -- least-toxic pesticides.

This method begins with correct identification of the plant or pest problem. Astute gardeners quickly learn that half of all plant problems are not caused by either disease or pests. This means investigating environmental factors that affect plant growth, such as soil, water, sunlight and nutrients, as well as cultural practices.

For example, shrubs planted too closely together may suffer fungal disease, but the problem is really lack of air circulation. The solution is to remove some of the shrubs or prune to thin foliage.

Likewise, a sun-loving plant in too much shade will be prone to problems that cannot be remedied with any amount of pesticide or fertilizer, whereas moving it to a sunnier location will do the trick.

IPM emphasizes that many plant problems can be prevented when gardeners choose plants appropriate for the site, provide the best growing conditions and monitor plants regularly.

The Home and Garden Information Center has an entire series of publications on IPM. All are available on our Web site or by calling our hotline.


1. Sow lettuce, spinach, radishes and other fast-growing salad greens in fertile soil. Keep the young plants well watered and fertilize with a weak balanced fertilizer solution.

2. Clean out nest boxes for song birds or install new ones.

3. Plant fruit trees, brambles, strawberry plants and grapevines as soon as the ground can be worked.

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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