Avoid horticultural heartache by choosing disease-resistant varieties

Last Updated: 
May 30, 2008

CORVALLIS, Ore. - When choosing plants for your yard and veggie garden, you'll save yourself a lot of heartache, as well as money, if you choose disease-resistant varieties, advises Jay Pscheidt, plant pathologist with the Oregon State University Extension Service.

"Planting resistant varieties is the easiest means of disease control," explained Pscheidt. "Roses, fruit trees and many vegetables such as tomatoes are susceptible to variety of diseases caused by fungi and viruses. Try and choose those marked 'disease-resistant' or 'certified virus-free' whenever possible."

For example, tomato seed packages and start tags often are marked with the letters V, N, T or F. V signifies resistance to Verticillium, a fungal disease causing premature wilt and reduced production. N stands for a nematode-resistant variety. Nematodes are small, wormlike pests that puncture root cells. T indicates resistance to tobacco mosaic virus, which causes mottled leaves. An F means the variety is resistant to Fusarium, a fungal disease that also causes wilt.

Tomato varieties known to be resistant to all of these diseases include Carmen, Carnival, Casino Royal, Cavalier, Celebrity, First Lady, Milagro and President.

Other vegetables have disease resistant or disease tolerant varieties as well, including green beans, peas, cucumbers, peppers and spinach.

The fungal diseases rust, powdery mildew and blackspot are common in rose gardens in the Pacific Northwest. Roses known to be resistant to these diseases include the hybrid teas Electron, Keepsake and Las Vegas; the floribundas Europeana, Liverpool Echo and Play Girl; and climbers Dortmund and Dublin Bay.

Apples are susceptible to a number of diseases including apple scab, fire blight and powdery mildew. Varieties that grow well, have shown good scab resistance and are of good quality include Akane (Tokyo Rose), Chehalis, Liberty, Prima and Tydeman Red.

Crab apples have the same problems, so Pscheidt recommends planting disease-resistant crab apple cultivars David, Indian Summer, Red Jewel or White Angel.

Consult catalogs and local nurseries for other disease-resistant varieties as well, as new ones come out each year and some of the old ones get discontinued.

For more information about disease resistance call the Master Gardener Program at your local county office of the OSU Extension Service.

Author: Carol Savonen
Source: Jay Pscheidt