Originally prepared for Vegetable MD Online by Thomas A. Zitter.
This page includes symptoms caused by:
Bacteria
Angular leaf spot | See factsheet for more information (LIHREC)
Symptoms: Brown spots, 1-4 mm in diameter, circular, water-soaked often with raised white center. Leaf symptoms also present.
Bacterial leaf spot | See factsheet for more information (LIHREC)
Symptoms: Brown spots varying greatly in size (up to a half dollar). Can develop into a water soaked rot that leads to fruit collapse. Leaf symptoms also present.
Fungi & Oomycetes
Anthracnose | See factsheet for more information (LIHREC)
Symptoms: Dark brown spots, circular, 2-5 mm, or larger in diameter, sunken with salmon-colored fungal growth under moist conditions or tiny black specks. Spots often develop in storage. Leaf and stem symptoms also present.
Fusarium dry rot | See factsheet for more information (LIHREC)
Symptoms: Tan, circular spots. Firm dry rot with white fungal growth. On surface side touching moist soil. Affected fruit may collapse without presence of white spores. Uncommon.
Gummy stem blight | See factsheet for more information (LIHREC)
Symptoms: Black spots, circular or irregular, can be large. Initially water-soaked, pinkish then turning black. Fruit often collapse due to other rotting organisms. Symptoms often develop in storage. Pycnidia often develop in storage. Pycnidia often develop. The foliar phase is called gummy stem blight black rot.
Phytophthora fruit rot | See factsheet for more information
Symptoms: Water-soaked or sunken spots which enlarge to encompass entire fruit. White yeast-like fungal growth on the surface, but some affected fruit may lack spores. Commonly observed on the side of the fruit which makes contact with soil. Leaf and stem symptoms also present. Localized occurrence.
Plectosporium blight | See factsheet for more information (LIHREC)
Symptoms: Light tan spots, small spindle-shaped, sunken, dry, scabby. Spots primarily on fruit handles and stems; sometimes on leaves.
Pythium
Symptoms: White spots, circular, 1-2 mm in diameter, raised like a rash. Leaf symptoms also present.
Scab
Symptoms: Beige or brown spots, dry and corky, small, circular. Initially sunken; can be raised. Leaf and stem symptoms also present.
Sclerotinia white mold
Symptoms: Watery, odorless rot. The pathogen produces a white cottony mold with black, hard, pea-like bodies. Develops in field or in storage. Localized occurrence, especially where beans or cabbage were grown.
Septoria
Symptoms: White spots, circular, 1-2 mm in diameter, raised like a rash. Leaf symptoms also present.
Phytoplasmas
Aster yellows
Symptoms: Fruit smaller and lighter in color than normal. Leaf symptoms also present.
Viruses
Cucumber mosaic virus | See factsheet for more information (LIHREC)
Symptoms: Fruit mottled, discolored (e.g. green blotches), distorted, bumpy, malformed. Plant stunted. Leaf symptoms also present.
Watermelon mosaic virus | See factsheet for more information (LIHREC)
Symptoms: Fruit mottled, discolored (e.g. green blotches), distorted, bumpy, malformed. Plant stunted. Leaf symptoms also present.
More information/prepared by:
- For more information, please contact:
Meg McGrath – mtm3@cornell.edu & Chris Smart – cds14@cornell.edu