Specks on Cucumber Leaves

Q: My cucumber leaves have small silver specks on them.  Is this normal or a problem?

A: The most common cause of specks on cucumber leaves is Alternaria Leaf Blight, a fungal disease that thrives in warm weather.  Sometimes the specks grow larger and form circular spots with a darker brown bullseye in the center and a yellow hallow around the perimeter of the spots.  Severely infected leaves turn brown, wither and die.  This disease is also common on cantaloupe, watermelon and squashes. 

Control:  Environmental/cultural practices need to be examined first.  Keep foliage dry, make sure the plants are getting at least 6 hours of direct sun per day, make sure there is good air circulation around and through the plants, and that they are not stressed by getting too dry at the roots.  Also, cucumbers are heavy feeders, so be sure to supply a good quality vegetable food regularly through the growing season.

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Read our Q & As with Keith Funk answering common Colorado gardening questions here. See his website: gardenwiseguy.com and hear him on the Garden Wise Radio Show