Plant Problems to Watch for in July


Here are some diseases we observed in the clinic during the month of July. The hypertext links will lead you to specific information about a certain disease or about diseases in a certain crop.

Field Crops

Corn Nutritional problems, Maize chlorotic dwarf virus
Cotton Root/stem rots (Rhizoctonia and Fusarium), Chemical injury
Peanut CBR, Southern blight (Sclerotium rolfsii), TSWV
Soybean Cyst nematodes, Pythium and Phytophthora root rot
Tobacco Black shank, Blue mold, Target spot, Granville wilt, Virus (TSWV, TMV, PVY, Etch, Ringspot) For more information, see the disease chapters in the production guides for flue-cured and burley tobacco

Turfgrasses (See TurfFiles Publications)

General Drought/hydrophobic soils, Normal summer death of annual ryegrass in overseeded lawns, Soluble salts injury
Bentgrass Fairy ring, Pythium diseases
Bermudagrass Dollar spot, Spring dead spot
Fescue Brown patch, Pythium blight
St. Augustinegrass Gray leaf spot

Woody Ornamentals

General Air pollution injury, Decline from cold injury last winter, Fertilizer injury, Low pH, Heat/drought stress, Mushroom root rot, Phytophthora root rot, Powdery mildew, Web blight
Azalea Stunt nematode, Phomopsis dieback
Boxwood Lesion nematodes (information for the nursery and landscape), Fertilizer injury
Cherrylaurels
(Otto Luyken, etc.)		 Bacterial leaf spot (shothole)
Crabapple Quince rust, Apple scab, Fire blight
Dogwood Dogwood anthracnose (Discula), Spot anthracnose (Elsinoe),
Powdery mildew
Elm Black spot, Dutch elm disease
Holly Black root rot, Nematodes (Dagger, Ring, Root-Knot)
Hydrangea Septoria leaf spot
Ivy, English Bacterial leaf spot, Anthracnose
Juniper Decline caused by combination of: low pH/magnesium deficiency, Phytophthora root rot, excess shade, spider mites, poor drainage
Leyland cypress Cypress canker (Seiridium), Botryosphaeria dieback/canker
Oak Leaf blister, Spot anthracnose, Tubakia leaf spot
Pear, Ornamental Fire blight, Quince rust
Periwinkle, Common Phoma blight, Rhizoctonia blight
Rhododendron Botryosphaeria dieback, Botrytis dieback
Rose Black spot, various cankers (Coniothyrium, Botrytis)
Waxmyrtle Botryosphaeria canker/dieback

Herbaceous Ornamentals

General on several summer annuals Anthracnose diseases, Botrytis blight, Chemical injury, Fertilizer injury, Pythium root rot, Rhizoctonia root/stem rot, Southern blight (Sclerotium rolfsii)
Black-eyed Susan Rhizoctonia crown rot, Southern blight
Coneflower and other asters Aster yellows
Coreopsis Alternaria leaf blight, Downy mildew, Powdery mildew, Rhizoctonia root/stem rot
Hosta Foliar nematodes, Southern blight, Slug injury
Impatiens INSV
Marigold Southern bacterial wilt
Pachysandra Volutella blight
Periwinkle, Madagascar Phytophthora blight

Interior Plants

Chrysanthemum Bacterial blight/leafspot, Fusarium wilt, Pythium root rot
Poinsettia Bacterial soft rot, Pythium root rot, Rhizoctonia stem rot

Fruits

Apple Alternaria blotch, Cedar-apple rust, Bitter rot, Fruit disorders (internal breakdown, growth cracks, water core), White rot
Stone fruits Brown rot, Short life complex, Scab
Blueberry Stem blight, Phytophthora root rot
Grape Anthracnose, Botrytis blight (bunch rot), Black rot, Downy mildew, Poor pollination
Strawberry Anthracnose, Black root rot complex, Common leaf spot, Phomopsis leaf blight

Vegetables/Herbs

General Rhizoctonia root/stem rot, Fertilizer injury, Southern blight, Nutritional problems
Green Bean Anthracnose, Common bean mosaic, Fusarium root rot
Ginseng Anthracnose, Alternaria leaf spot, Web blight (Rhizoctonia)
Crucifers Club root, Downy mildew, Nutritional problems
Cucurbits Alternaria leaf spot, Anthracnose, Bacterial wilt, Downy mildew, Nematodes, Fusarium wilt, Gummy stem blight, Viruses, Powdery mildew (See also Cantaloupe diseases)
Pepper Southern blight, Bacterial spot, Blossom-end rot, Phytophthora stem rot
Tomato Bacterial spot, Blossom-end rot, Early blight, Fusarium wilt, Leaf mold, Pith necrosis, Southern blight, Southern bacterial wilt, TSWV, Stemphylium gray leaf spot, Septoria leaf spot, Tobacco mosaic virus

Other Links

Plant Clinic Summaries
Plant Disease Information Notes
Plant Disease and Insect Clinic

Last modified November 2000