Diseases

Here you’ll find a list of diseases that can occur in gardens, with recommend treatment approaches.  Many diseases can be prevented with healthy soil, crop rotation, planting resistant varieties, and planting certified, pathogen-free seed.  Sometimes the best treatment will be to remove a plant and start over!

Our color-coding system will alert you to areas of concern: Look for green, yellow, or red “lights” for each entry.

Fusarium Wilt

Gardeners take note

Causes yellowing and wilting of foliage. Plants can be affected at any stage from seedling to harvest, but the majority of plant death appears to occur when plants are in seedling stage to four-leaf stage of growth.

Powdery Mildew

Low / None

Powdery mildews are characterized by spots or patches of white to grayish, talcum-powderlike growth. Tiny, pinhead-sized, spherical fruiting structures that are first white, later yellow-brown and finally black, may be present singly or in a group. These are the cleistothecia or overwintering bodies of the fungus. The disease is most commonly observed on the upper… Read more »

Rust

Gardeners take note

Rust symptoms initially appear as small yellow or white slightly raised spots on upper and/or lower surfaces of leaves. These spots enlarge and form reddish-brown or rust-colored pustules that are about 1/8 inch in diameter and contain thousands of microscopic summer spores (urediniospores). Spores (fungus seeds) are readily released from the pustule and give a… Read more »

Affects

Sunscald

Can be a serious problem

Sunscald occurs when peppers or other vegetables are exposed to the direct rays of the sun during hot weather; the damaged areas may become papery and bleached or tan colored, and these areas often are covered with a black fungal growth. It is more apparent on plants that have sparse foliage or that have lost… Read more »

Affects

Tomato Spotted Wilt

Can be a serious problem

Symptoms begin and dark or purple spots on leaves. The dark areas spread to stems, forming cankers. Stem streaking also may be noticed. Wilting symptoms gradually develop as the disease spreads. However, the leaf tissue is stiff, not limp. The most noticeable symptoms are yellow rings or spots on fruit. Fruit may be distorted. The… Read more »

Affects

Verticillium Wilt

Gardeners take note

A mottling of the lower leaves becomes apparent, but disease symptoms progress up the plant as plants near maturity. Tissue between leaf veins become yellow, then brown,giving diseased leaves a mottled appearance. Diseased leaves eventually wilt, become completely dry, and die. A blackening of the stems is often apparent, especially near the soil line. Infected… Read more »

Affects