Cucumber Plant Wilting

If your cucumber plant starts wilting suddenly and it's not due to insufficient watering or extreme heat, it is most likely caused by the cucumber beetle.

Once a plant is infected with bacterial wilt, there's not much you can do. There are preventative measures to control these pests though. The best preventative measure is making sure your plants are strong and healthy before they go in the ground or choosing cucumber varieties that are resistant to this pest.

I prefer not to use insecticides, even organic ones like neem oil and Diatomaceous earth, because they also affect beneficial Insects. There are also yellow sticky traps which cucumber plants are attracted to, but these also trap beneficial Insects sometimes.

Successive planting is also a solution to replace your dying plants with new ones.

Good luck gardening.