Cucumber question

Hi all - for the first time I finally have a successful cucumber & squash crop coming along. I checked on them yesterday and I noticed little flies (light color or white) flying around when I disturbed the leaves. Some of the leaves of the cucs do have spots on them but all of the fruit is beautiful. I sprayed Seven liquid on them last night but that didn't do anything.

My question: does anyone know what these could be and are they harmful? What do I need to do?

Help!!!

Thanks!!
GG

Sounds like White Flies. Sevin will not touch them. Biggest danger is that they transmit virus. Call your County Agent.
http://www.sciencedaily.com/releases/2008/04/080420113317.htm

White flies usually appear in damp conditions with poor air circulation.I grow my cucumbers on the garden fence.They are more than happy to climb the fence.This helps eliminate critters because the leaves don't stay wet.It also makes them much easier to harvest and they take up less garden space.
As for the squash try to give them plenty of space.This helps them stay a little drier.As with any plant never water at night.Watering at night encourages lots of critters to visit your garden especially slugs.
Underwatering is less of a problem than overwatering.
I hope this helps.

Thank you both very much! I am heading out to put my vines up on something so air can get around them!!!