If you can identify symptoms you could be able to successfully avoid the chance of disease in your plants, even if you don’t know exactly what’s causing the infection. Here are the most common garden plant diseases and disorders.
The Most Common Garden Plant Diseases and Disorders: Part One
Blights: This is when the plants suffer from blight, their leaves or branches suddenly wither, they stop growing, and die. Later, plant parts may rot.
Fire blight: This bacterial disease affects apples, pears, fruit trees, roses, and small fruits. Plants that are affected will wilt and look blackened.
Alternaria blight (early blight): This fungal blight infects ornamental plants, vegetables, fruit trees, and shade trees worldwide. Brown to black spots form and grow bigger on leaves, developing concentric rings. Heavily blighted leaves will dry up and die as spots grow together. You can control this disease by planting resistant cultivars and growing your own transplants from disease-free seed while promoting good air circulation.
Phytophthora blight (late blight): Lilacs, rhododendrons, azaleas, and holly that are infected by Phytophthora fungi suffer dieback of shoots and develop stem cankers. If this occurs, you should prune to remove infected branches and increase air movement. The first symptom of this is water-soaked spots on the lower leaves. The spots grow and are mirrored on the bottom of the leaf with a white downy growth. You can avoid problems by planting in well-drained soil, and use resistant varieties if possible. Foliage should be kept as dry as possible. If plants are infected, you should immediately remove the plants and prune off cankered shoots of shrubs.
Bacterial blight: This bacterial disease is especially hard on legumes in eastern and southern North America. Foliage and pods display water-soaked spots that dry and drop out. Lesions are long and dark colored on stems and some spots may ooze a nasty bacterial slime. To control this issue, plant resistant cultivars, remove infected plants, and dispose of plant debris. You should also avoid touching the plants while they’re wet because you may spread the disease.
Cankers: Cankers typically occur on woody stems and may be in cracks, sunken areas, or raised areas of dead or abnormal tissue. Sometimes cankers ooze. Cold-injury symptoms may lead to the development of cankers and diebacks.
Cytospora canker: This fungal disease attacks poplars, spruces, and stone fruits. They are circular, discolored areas on the bark. To control, you should plant resistant trees and cut out branches or trees that have been affected with cankers.
Nectria canker: This fungus attacks most hardwoods and some vines and shrubs, but is most damaging on maples. Small sunken areas appear on the bark near wounds, and small pink spore-producing structures are produced. It kills twigs and branches and may girdle young trees. Nectria cankers can be controlled by limiting pruning cuts and removing diseased branches.
Diseases and disorders in plants can be hard to avoid, but if they do occur, fungicides, such as Pure 3-Way, are a great way to bring your plants back to health.