Do You Have a Gardening Question?

The Oregon State University Extension Center Plant Clinic is a research-based diagnostic facility staffed by Master Gardener volunteers. The primary mission of the Plant Clinic is educational. We help local residents recognize the nature of their plant or insect problem (diagnosis) by helping them to manage the disease or disorder using proper control methods, including cultural, biological and chemical measures. Emphasis is on prevention of problems by proper management.

To receive the best possible answer to your query, you should:

  1. Provide Master Gardener volunteers with as much information as possible, regarding your problem or your inquiry,
  2. Provide a sample of the plant or insect with which you have a concern,
  3. Provide a photograph of the plant or section of your yard with which you have a concern especially when it is not possible to bring in a physical sample, and
  4. Allow the Master Gardener volunteers the time that they need to comprehensively research your question.

A Master Gardener volunteer will research an answer to your question, using a variety of library and online resources. It is important to remember that Master Gardener volunteers exclusively use non-biased, science-based information in their research. This restriction on the materials that Master Gardener volunteers can use, when providing a recommendation to the public, ensures that the answer you receive is high quality and unbiased.

Phone – 541-776-7371, ext. 204


Plant Clinic Hours:

Winter Hours

November – March
10AM-2PM Tuesdays & Thursdays

Spring & Summer Hours

April – October
10AM-2PM Monday – Friday

The Plant Clinic is located at:

Southern Oregon Research and Extension Center
569 Hanley Rd
Central Point, OR 97502

Common Problems


Aphids, also known as plant lice are small sap-sucking insects. Wash off plants with strong stream of water.  Don’t over fertilize with nitrogen or overwater.  Control ants which “farm” aphids.  Encourage natural enemies.  Treat chemically with insecticidal soap, neem oil, horticultural oil, pyrethrins.


Earwigs frequent moist mulch and areas beneath leaves. Remove debris and other hiding places.  Search for insects at night with a flashlight to confirm identity.  Trap with damp rolled-up newspapers.  Treat chemically with pyrethrins, spinosad, iron phosphate.

Powdery Mildew

Powdery mildew is a fungal disease that affects a wide range of plants. Use resistant varieties, provide good air circulation, avoid shading of plants, pick affected leaves off before disease widespread on plant.  Treat chemically with neem oil or other fungicides.

Codling Moth

Codling moth is known as an agricultural pest, common in apple orchards. Monitor for adults with traps in spring. Clean up fallen fruit, leaves and other debris.  Apply chemicals 10 days after full petal fall or at 250 degree-days (check with Plant Clinic for date).  Treat again at 1000 degree days (usually early July).   Treat with spinosad or CYD-X.

Blossom End Rot

Blossom end rot, a relatively common garden problem, is not a disease, but rather a physiological disorder caused by a calcium imbalance within the plant. Avoid over-fertilizing with nitrogen.  Ensure uniform soil moisture while fruiting.  Mulch around plants.  If a soil test shows calcium deficiency, add lime in fall to bring pH to 6.8-7.0.


*Be sure to read and follow all directions on chemical labels.