Detailed profiles of common plant diseases, pests, nutrient deficiencies and environmental problems.
Azalea leaf and flower gall is a fungal disease associated with Exobasidium vaccinii. On azaleas and rhododendrons it produces swollen, thickened, curled leaves, flowers…
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Grape powdery mildew is a widespread fungal disease of grapevines caused by Erysiphe necator. It produces white to gray powdery colonies on leaves, shoots,…
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Apiaceae powdery mildew is a fungal disease caused by Erysiphe heraclei and reported mainly on carrots, parsley, parsnips, cilantro, celery, fennel and related plants…
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Beet powdery mildew is a host-specific fungal disease of sugar beet, table beet, and other Beta plants. It appears first as small, white, powdery…
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Oak powdery mildew is a superficial fungal disease caused by Erysiphe alphitoides, a host-specialized powdery mildew associated primarily with oaks. It produces conspicuous white,…
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Fire blight is a destructive bacterial disease of apple, pear and many other members of the rose family, caused by Erwinia amylovora. Blossoms, shoots,…
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Pearleaf blister mite is a microscopic eriophyid mite that feeds beneath pear bud scales and inside developing leaves. Feeding produces raised pink, yellow-green, brown,…
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Entomosporium leaf spot is a fungal disease of many woody plants in the rose family, especially red-tip photinia, Indian hawthorn, pear, quince, pyracantha, loquat,…
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The smaller green leafhopper, Empoasca vitis, is a sap-feeding leafhopper associated especially with grapevines in European vineyards. Nymphs and adults feed on the undersides…
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Grape anthracnose, also called bird’s-eye rot or grapevine black spot, is a fungal disease caused by Elsinoë ampelina. It attacks young green tissues during…
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Rosy apple aphid, Dysaphis plantaginea, is a host-alternating aphid that attacks apple in spring, causing tightly curled leaves, distorted shoots, and misshapen fruit. Winged…
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Spotted-wing drosophila, Drosophila suzukii, is an invasive fruit-fly pest of ripening soft-skinned fruit in the United States. Unlike common vinegar flies, females can pierce…
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