Detailed profiles of common plant diseases, pests, nutrient deficiencies and environmental problems.
Plenodomus biglobosus is a fungus associated with blackleg, or phoma stem canker, of canola, oilseed rape and other Brassicaceae. It commonly produces leaf spots…
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Grape downy mildew is a destructive disease of grapevines caused by the oomycete Plasmopara viticola. It favors warm, rainy or persistently humid weather and…
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Phytophthora root and stem rot is a serious soybean disease caused by the soilborne oomycete Phytophthora sojae. It can destroy seedlings before emergence or…
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Phytophthora plurivora is a water-mold pathogen associated mainly with woody plants in nurseries, landscapes, orchards and forests. It attacks fine roots, larger roots and…
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Phytophthora palmivora is a water-mold pathogen that causes bud, spear, crown, root, stem, and fruit rots in warm, humid conditions. It is especially important…
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Phytophthora citrophthora is a soil- and water-associated oomycete best known in the United States for citrus brown rot, but it can also contribute to…
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Phytophthora cambivora is a soil- and water-associated oomycete that attacks roots, crowns and sometimes the lower trunk of woody plants. It is best known…
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Alder Phytophthora is a serious root and collar disease associated mainly with alder trees (*Alnus* spp.). The water-mold pathogen *Phytophthora alni* can cause fine-root…
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Purple-bordered leaf spot is a common, usually cosmetic fungal disease of maple leaves caused by Phyllosticta minima. It produces circular tan to brown lesions…
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Citrus black spot is a regulated fungal disease caused by Phyllosticta citricarpa. It produces dark, sunken blemishes on ripening citrus fruit, sometimes leaf and…
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Ash powdery mildew is a fungal disease of ash trees caused by Phyllactinia fraxini. It produces conspicuous white, powdery growth mainly on the undersides…
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