To see diseases and pests specific to the crop you are growig, find the crop by name in the Topic Index and click through or check crops by name in the How To Grow archive.
•Description. Fungus disease. Over-winters on infected seed, plant debris, or in the soil. Wet weather promotes growth; optimum growth between 78°F and 86°F.
•Damage. Dark brown circular sunken spot on stems, leaves, pods or fruit. Centers of lesions may ooze pink spore masses. Reddish discoloration of the leaf veins. Leaves may wither and fall. Plant may die back.
•Spread.Over-winters in garden in debris of diseased plants. Spread by wind, rain, animals, gardeners, tools. High humidity, high rainfall, and high temperatures encourage spread. Generally found in eastern North America.
•Prevention and controls. Spray or dust with a fixed copper- or sulfur-based fungicide every 7 to 10 days. Remove and discard infected plants. Do not save seed infected planting area; use western-grown seed or seed from areas not infected. Rotate crops. Avoid working in the garden when it is wet which can result in spread of spores. Keep tools clean.
•Description. Fungus disease of massed reddish or black spores grows on asparagus ferns.
•Damage. Tiny, rust-colored spores mass on asparagus ferns. Black spores mass in late summer. Fern growth is retarded. Yield is reduced. High humidity and wet weather encourage spread.
•Susceptible plants. Asparagus.
•Spread. Rust spores are blown by the wind or carried by gardeners, tools, animals or insects. Spores can over-winter in plant debris. Heavy dew and high humidity encourage this disease. Found throughout North America.
•Prevention and controls. Plant resistant varieties. Cut plants to the ground at the end of each season. Remove and destroy plant debris. Keep water off of leaves. Use a preventative sulfur spray or dust every 7 to 10 days until 3 or 4 weeks before harvest.
•Description. Bacterial disease. Most severe where humidity is high for long periods.
•Damage. Beans: large brown blotches bordered with yellow or red on leaves of beans. Water-soaked spots on pods. Pea stems turn purple or nearly black near the ground. Small water-soaked spots on leaves; yellow to brown spots on pods enlarge to reddish color.
•Susceptible plants. Beans, peas.
•Spread.Bacteria enter plants through small openings and wounds. Spread by wind, infected seeds. Over-winters in plant debris. Most severe where humidity remains high for long periods. Found throughout mid-North America, but rarely west of the Rocky Mountains.
•Prevention and controls. Remove infected plants and discard them. Bacterial blight can not be cured. Do not save seed from infected area. Rotate crops. Avoid working in the garden when it is wet; this may result in spread of disease.