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.
Gardeners take note
Leaf symptoms begin as small, pale yellow or water- soaked lesions that rapidly enlarge and turn tan to dark brown or irregular and black. As lesions merge, large areas of the leaf may appear blighted or entire leaves may die. Young cucurbit fruit may turn black, shrivel, and die if fruit pedicels are infected. Anthracnose… Read more »
Gardeners take note
Symptoms begin as small, yellow-green lesions on young leaves which usually appear deformed and twisted, or as dark, water soaked, greasy-appearing lesions on older foliage. Lesions develop rapidly to a size of 0.1 to 0.2 in wide and become tan to brownish-red. Fruit spots begin as pale-green, water- soaked areas, which eventually become raised, brown,… Read more »
Gardeners take note
Symptoms begin as small, yellow-green lesions on young leaves which usually appear deformed and twisted, or as dark, water soaked, greasy-appearing lesions on older foliage. Lesions develop rapidly to a size of 0.1 to 0.2 in wide and become tan to brownish-red. Fruit spots begin as pale-green, water- soaked areas, which eventually become raised, brown,… Read more »
Gardeners take note
Leaves of older infected plants will wilt, especially during moisture stress and warmer parts of the day. Golden brown, irregularly-shaped leaf lesions occur, and affected leaves wilt and may drop off. Infection can occur on pod sutures similar to that caused by other bacterial diseases, but seldom will it produce circular water-soaked spots.
Gardeners take note
Causes a mottled light and dark green mosaic-like pattern on leaves (they often look like they are variegated) and downward cupping along each leaflet. Depending upon the age, variety of plant and strain of virus they may not have a significant effect on the plant or they may cause stunting and severely reduce the harvest.
Gardeners take note
A plant disorder that is caused by a calcium deficiency. If demand for calcium exceeds supply, tissue lacking the mineral break down, causing a leathery brown or black area on the blossom end of fruit. This normally occurs on the first fruit set of the season. Most common when season starts out wet and then… Read more »
Gardeners take note
Infected plants wilt during the day and their leaves are commonly curled, or thickened, cupped, yellowed or rolled inward. Sometimes the veins on the undersides are purplish in color. All plants are stunted and don’t grow well, or produce any more fruit. Commonly spread by leafhoppers.
Gardeners take note
Infected seeds don’t germinate, instead they turn mushy and brown. Seeds may be attacked upon germination and before seedlings emerge from the soil. Infected seedlings get a dark, water-soaked area on the stem at the soil line. Damage spreads rapidly, and seedlings collapse and fall over as the stem collapses. Older plants that are infected… Read more »
Gardeners take note
Caused by parasitic organisms that are closely related to algae (not a true fungus). Most likely to appear during wet, cool weather. First symptoms could be mottling of spotting of the leaves (could be yellow, light green, brown or purple. You will also see a fuzzy, soft looking growth that can be white, grey, brown… Read more »
Gardeners take note
Tomato plants that have spots that start as small, dark brown to black areas, and are turning yellow on the lower part of the plant, may indicate the presence of early blight. As the spot develops, a concentric ring pattern can frequently be detected. This is the most diagnostic symptom of the disease and is… Read more »
