WSU Extension


Cucumber, Pumpkin, Squash
Angular leaf spot 
Cucumber mosaic virus 
Curly top (Beet curly top virus) 
Pollination failure 
Powdery mildew 
Root rot 
Verticillium wilt 
White mold 
Brown marmorated stink bug 
Spider mites 
Squash bug 
Western spotted cucumber beetle 

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Cucumber, Pumpkin, Squash : Pollination failure
(revision date: 6/3/2014)

Fruits may begin to develop without pollination, but must be pollinated to continue normal growth. The unpollinated fruit remain small and may show a rot beginning at the blossom end. These fruits usually turn yellow and drop from the plant fairly quickly. Incomplete pollination may also be a problem, resulting in misshapen fruit (curved, bell-shaped, or nubbins). Portions of the fruit may have abnormal seed development. Both male and female flowers are necessary for pollination to occur (except in some cucumbers). Since female flowers typically appear on the vines before male flowers, the earliest female flowers are not usually pollinated.
Management Options

Non-Chemical Management
  • Hand-pollination may be necessary in small plantings. A single male flower can be used to pollinate several female flowers.
  • Low temperatures may prevent flower development and pollination.
  • Some species produce male and female flowers on separate plants. For these species, be certain to plant both male and female plants.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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