The cucumber plant looks like it has bacterial wilt. Unfortunately, this is a common disease in cucumbers. It is spread by the feeding of cucumber beetles. This same disease also occurs in zucchini, squashes, and pumpkins. Here are two web pages with more information about bacterial wilt and the cucumber beetles -- and what to look for.
https://extension.umd.edu/growit/bacterial-wilt-vegetables
https://extension.umd.edu/growit/insects/cucumber-beetles-spotted-or-striped

Once this happens, there really isn't much you can do but take the plants out and discard them. There is no cure for it. For next year, plan to grow disease resistant varieties. The variety of cucumber called 'County Fair' has disease resistance. Other options are listed on the Cornell University web site: http://vegvariety.cce.cornell.edu/main/showVarieties.php?searchCriteria=cucumber&searchIn=1&...
You can also use floating row covers over your plants to exclude the beetles from feeding.
https://extension.umd.edu/growit/beyond-basics/floating-row-cover

Several things can cause wilting in tomatoes: drought or waterlogged soils, or diseases.
http://extension.umd.edu/growit/fusarium-wilt-tomato-vegetables
To check if it is a disease, you can cut the tomato stem lengthwise and see if there is any browning inside (see the photo at the link above). If you see the browning, this confirms wilt disease. Next year, you should not plant tomatoes in the same place, as the disease can carry over in the soil. Fusarium wilt is the more common type of tomato wilt disease. Cornell has a good list of disease resistant tomatoes. http://vegvariety.cce.cornell.edu/main/showVarieties.php?searchCriteria=tomato&searchIn=1&cr...

ckc
 

Thanks for your response. So, for the fusarium I don't need to do anything but not plant tomatoes there for one year? No type of soil remediation? 

Also, is it harmful to eat the vegetables that are produced? 

Thank you. 

You could replace the soil where you have your tomatoes planted. If you do see brown discoloration inside the tomato stem (confirming wilt disease) it is still safe to eat the tomatoes. The pathogen is not harmful to people.

ckc