Crop |
Disease |
Symptoms |
Alliums (Garlic, Leek, Onion)
|
Downy Mildew |
Early symptoms are sunken spots on leaves; later, a purplish mold develops over spots |
Pink Rot |
Roots turn pinkish or red, eventually rot; plant is stunted with wilted tops |
Smut |
Black spots on leaves and between the sections of the bulbs; young plants may have twisted leaves; common in northern regions |
Asparagus
|
Asparagus Rust |
Reddish-yellow spots on stems, branches; gradually entire plant yellows, weakens, and eventually dies |
Fusarium Wilt |
Wilted, stunted spears with brownish surface color |
Bean, Lima
|
Bacterial Spot |
Reddish-brown lesions on stem leaves, and pods; young diseased pods may fall from plant |
Downy Mildew |
Plants are mottled with white, fuzzy fungus strands on them. |
Bean, Snap
|
Anthracnose |
Dark red, sunken spots on leaves and stems; pinkish-red spots on pods; seeds are often black |
Bacterial Blight |
Large brown blotches on leaves, possibly bordered with yellow or red; water-soaked spots on pods; seed may be discolored |
Mosaic |
Leaves crinkled with mottled areas; pods may be rough misshapen |
Rust |
Many small reddish-orange to brown spore masses on leaves and possibly stem; leaves rapidly yellow dry up, and drop |
Beet |
Leaf Spot |
Small, round, tan to brown spots on leaves and stems; later leaves turn yellow and drop |
Brassicas (Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Turnip) |
Black Rot |
Leaves yellow, veins become black; plant becomes stunted and heads of cabbage, cauliflower, or Brussels sprouts are one-sided or nonexistent; stem cross section shows a brown, woody ring |
Carrot
|
Leaf Blight |
Yellow to whitish spots on leaves; girdling of roots; water-soaked spots or lesions on roots |
Root-Knot Nematode |
Small galls on lateral rootlets; pimple-sized swellings on main root; plants may be yellow and stunted |
Celery
|
Blights (Early and Late) |
Greenish or water-soaked spots on leaves; sunken lesions possible on stalks; growth may be visible in wet weather |
Fusarium Wilt (Celery Yellows) |
Reddish tissue on stalks and leaves; yellowing of foliage |
Pink Rot |
Water-soaked spots on stalks; bitter-tasting, rotted stems; damping-off may occur in an infected seedbed |
Corn
|
Bacterial Wilt |
Pale, streaked leaves; yellow, sticky substance exudes from a cut stem |
Corn Smut |
Large galls develop on stalk, ears, and roots; later, grayish galls blacken and release spores; ripened spores appear oily or powdery |
Cucurbits (Cucumber, Pumpkin, Squash)
|
Anthracnose |
Small, dark spots on leaves; eventually spots grow together and entire leaf is destroyed; frutis may blacken and drop; problem develops in warm, moist conditions |
Bacterial Wilt |
Leaves wilt quickly, possibly while still green; white, sticky material might be seen when a stem is cut |
Downy Mildew |
Yellow to purplish spots start on leaves, gradually cover entire plant |
Mosaic |
Leaves of cucumber and squash develop rough, mottled surface; cucumber fruit may be entirely white; plant may be stunted and yellow in several places |
Powdery Mildew |
Round, white spots on undersides of leaves; eventually entire leaf is covered with powder; fruits ripen prematurely and have poor flavor and texture |
Scab |
Dark spots on fruit of cucumber and pumpkin; leaves may have water spots and stems may have shallow lesions; sap oozes from fruits, then greenish mold develops |
Eggplant
|
Fruit Rot |
Brownish spots on leaves; damage is particularly bad during wet weather when fruit may develop small, tannish cankers which later rot |
Verticillium Wilt |
Yellowing of foliage and gradual defoliation; plants may become stunted |
Pea
|
Ascochyta Blight |
Leaves shrivel and die; roots and lower stems may blacken and rot; disease overwinters on plant debris |
Bacterial Blight |
Brownish or yellow blotches form on leaves and pods; stems may turn purplish; leaves eventually yellow |
Powdery Mildew |
Stems, leaves, and pods dusted with white powdery mold; black specks appear later in the season; plants are stunted and vines shriveled |
Root Rot |
Yellowed, gangly plants with rotting roots and lower stems; plant may die before pods form |
Pepper
|
Anthracnose |
Dark, round spots on fruit; entire pepper may rot or dry up; serious problem particularly in southern or central regions |
Bacterial Spot |
In dry areas, leaves develop yellowish spots with darker margins; older leaves eventually drop |
Potato
|
Blackleg |
In warm, moist climates, plants become stunted and leaves yellow and roll; stem base develops brown, rotted areas on the inside; inside of tubers shows darkened blotches and a soft rot that worsens during storage |
Early Blight |
Spots develop in rings on leaves; eventually leaves may die; tubers develop puckered skin and shallow rough lesions; mold may result |
Mosaic |
Mottled, crinkled foliage; brown specks appear on tubers, and plants may droop and die prematurely |
Rhizoctonia |
Dark brown cankers appear on young sprouts; mature stalks may become brown; tubers are covered with hard, black “scurfs”; tubers may also be roughened in a cross-patched pattern |
Verticillium Wilt |
Late in season, older leaves yellow; affected vines die prematurely; stem tissue discolors from base; tubers may be pinkish |
Spinach (also Swiss Chard)
|
Blight |
Yellowish, curled leaves; stunted leaves and plants |
Downy Mildew |
In moist areas, leaves develop yellow spots with fuzzy, purplish growth beneath |
Sweet Potato
|
Black Rot |
Small, round, brown spots on potato tubers; stem may also show decay |
Soft Rot |
Soft, watery rot on stored tubers |
Stem Rot |
Young infected plants may die after trans-planting; survivors develop bright yellow leaves, and later stems rot; harvest is of poor quality |
Tomato
|
Anthracnose |
Fruits develop small, round, water-soaked spots; later, fruits darken and rot |
Blights (Early and Late) |
Irregular, water-soaked spots may develop on leaves; plant becomes partly defoliated; seedlings may girdle; stem end of fruit becomes grayish-green; blossoms or young fruits may drop |
Fusarium Wilt |
Leaves yellow and droop; cross section of stem shows brownish liquid within; fruit usually decays and drops |
Mosaic |
Mottled leaves; young leaves are bunched or puckered; plants are stunted; yield is reduced; in some types of mosaic, fruit is also mottled |