Dealing With Vegetable Diseases: Fungi


| 8/30/2013 5:50:00 PM


Karen NewcombFungi are minute non-green plants that exist everywhere in the garden soil. One pound of soil contains up to 225 million of them.  Like bacteria, some fungi break down organic matter into nutrients that can be used by vegetables. In contrast, other fungi attack live plants. With the exception of rots, fungal diseases tend to start with a sunken dark area that is later bordered by yellow, tan or light green.

You will find eight general types of fungal infections in your garden: mildews, rusts, rots, cankers, scab, spots, wilts and smuts.

Mildews fall into two groups – powdery and down mildew. Powdery mildew shows up as superficial white to light grayish patches on the upper surfaces of leaves and on buds. Plants infected with downy mildews have pale green or yellow areas on the upper leaf surfaces, with light gray or purplish patches below. The leaves wilt, wither and die. Seedlings may wilt and collapse. Both mildews affect a wide number of vegetables. Mildew attacks are most severe in cool, humid or wet weather and are common in areas with cool nights and warm days.

Mildew

Mildews. Courtesy David B. Langston, University of Georgia



Prevention or natural controls: Rotate crops; avoid overhead sprinkling; plant resistant varieties.