It's too early for cucumber beetles and the bacterial wilt that they may spread. They overwinter in the soil and emerge when temperatures are warm and you'd see them and the feeding damage they do to the leaves.
What's the soil and air temperature in the greenhouse Jeannine? Cucumber like all Corcubits I know hate cool temperatures. I don't have a greenhouse and I never start Corcubits until mid May indoors and only transplant them in the ground or containers when the threat of cold weather and frost is no longer.
If you are plagued by cucumber beetles and bacterial wilt in the summer, read and learn.
http://tomatoville.com/showthread.ph...cumber+Beetles