Plant problem library

Disease

Cercospora leaf spot

Cercospora beticola Sacc.

Cercospora leaf spot is a fungal disease of beet, Swiss chard and spinach caused by Cercospora beticola. It begins as small, circular gray, tan…

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Disease

Canker Stain of Sycamore

Ceratocystis platani

Canker stain is a lethal vascular disease of sycamores and plane trees caused by the fungus Ceratocystis platani. It commonly begins with thinning foliage,…

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Disease

Ceratocystis Wilt, Canker, and Black Rot

Ceratocystis fimbriata Ellis & Halst.

Ceratocystis fimbriata is a wound-infecting fungus associated with several serious diseases, including black rot of sweetpotato, Ceratocystis canker of almond, mango wilt, and wilt…

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Disease

Stolbur Phytoplasma Disease

‘Candidatus Phytoplasma solani’

Stolbur phytoplasma disease is caused by the wall-less, phloem-limited bacterium ‘Candidatus Phytoplasma solani’. It is associated with stolbur in potato, tomato and other crops,…

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Disease

Pear Decline

‘Candidatus Phytoplasma pyri’

Pear decline is a phloem-limited disease caused by ‘Candidatus Phytoplasma pyri’. In the United States, it is mainly spread by pear psylla (Cacopsylla pyricola)…

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Disease

European Stone Fruit Yellows

‘Candidatus Phytoplasma prunorum’ Seemüller and Schneider

European stone fruit yellows is a serious, vector-borne phytoplasma disease of Prunus trees caused by ‘Candidatus Phytoplasma prunorum’. It is especially damaging to apricot,…

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Disease

Apple Proliferation Disease

‘Candidatus Phytoplasma mali’

Apple proliferation is a systemic phytoplasma disease caused by ‘Candidatus Phytoplasma mali’, primarily affecting apple trees. It produces witches’ brooms, enlarged stipules, leaf rosettes,…

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Disease

Aster yellows

‘Candidatus Phytoplasma asteris’

Aster yellows is a systemic, leafhopper-transmitted disease caused by ‘Candidatus Phytoplasma asteris’ and related strains. It affects many vegetables, ornamentals, weeds and some woody…

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Disease

Boxwood blight

Calonectria pseudonaviculata

Boxwood blight is a destructive fungal disease caused by Calonectria pseudonaviculata. It produces dark leaf spots, rapid browning and leaf drop, and distinctive black…

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Disease

Pine Wilt Disease (Pinewood Nematode)

Bursaphelenchus xylophilus

Pine wilt disease is a rapidly progressive disease of susceptible pine trees caused by the pinewood nematode, Bursaphelenchus xylophilus. Pine sawyer beetles in the…

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Disease

Shallow Bark Canker of Walnut

Brenneria nigrifluens

Shallow bark canker is a bacterial disease associated primarily with English walnut, caused by Brenneria nigrifluens. It produces scattered brown-to-black bark spots, shallow necrotic…

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Disease

Lettuce Downy Mildew

Bremia lactucae Regel

Lettuce downy mildew is a cool-weather foliar disease caused by the obligate oomycete Bremia lactucae. It produces pale green to yellow angular lesions on…

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