plant diagnostic_database

                               Cucumber (Cucumis sativus)                          


Affected Area:

Plant Information:

Cucumbers are members of the cucurbit family, which are a warm weather, sun requiring vegetable.  Types of cucumbers include long, smooth, green slicing types; small pickling types; and roundish, yellow, mild-flavored lemon cucumbers.  Novelties include oriental(long, slim, very mild), Armenian(actually long, curving, pale green, ribbed melon with cucumber look and mild flavor) and English.

Cucumbers grow best in soils with a pH of 5.5-7.0 and 60°F.  Set transplants out or plant seeds when all danger of frost is past.  In small gardens they can be trained to climb a fence.  Provide plenty of moisture and harvest fruits while they are dark green, if they turn yellow the plant quits producing.



Affecting Leaves and Vines:
Signs or Symptoms      Cause
Plants wilt, foliage looks burned; preceded by pale green areas forming on leaves Squash bug (Anasa tristus)
Sudden wilting of a runner or part of a runner Squash vine borer (Melitta satyriniformis)
Leaves wilt, yellow, and curl High Aphid populations
Vines wilt and die gradually, starting with newer leaves; no leaf yellowing is present Bacterial wilt (Erwinia tracheiphila)
Small, pitted leaf holes on young plants Cucumber beetles (Acalymma vittata)
Distorted, Yellow spots on leaves with mottling and wrinkling of older leaves Mosaic viruses
Older leaves mottled yellow between veins Downy mildew (Peronospora effusa)
Powdery, white spots on upper surface of leaves especially Powdery mildew
Leaf spots that begin as water-soaked, then turn gray, die and drop out leaving foliage with a shot-hole appearance Angular leafspot (Pseudomonas syringae)
If water-soaked, yellow spots turn brown Anthracnose
Affecting Fruit:
Signs or Symptoms Cause
Small, brown, angular fruit spots Angular leafspot (Pseudomonas syringae)
Brown and sunken zoned spots Alternaria (Alternaria spp.)
Circular, black, sunken cankers Anthracnose
Misshapen, yellow mottled fruit, often with a bitter taste Mosaic virus
Fruit wilts and shrivels Bacterial wilt (Erwinia tracheiphila)
Fruit is narrow at stem end Potassium deficiency
Fruit has a dull bronze color Phosphorus deficiency
Fruit is light colored Nitrogen deficiency
Dark pitting of fruit Cold damage

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