Q. Why are my cucumber plants leaves turning yellow and dying?
It sounds like your cucumbers have bacterial wilt. This is usually transmitted by the striped or spotted cucumber beetle. Here is a way to tell if your plants have bacterial wilt. To determine if a plant is infected with bacterial wilt, press together two freshly cut sections of a stem and slowly pull them apart . If a "stringy" sap (bacterial growth and associated resins) extends between the cut ends, the plant has bacterial wilt. If they are affected badly there really isn't much you can do at this stage, other than to replant. The beetle tends to be most active from dusk to early morning so you could cover your plants with a row cover then, or before blooming. If they are blooming you need to be sure to uncover during the day so the pollinators can get to them. You can check the internet for more information. One web site says to use Merit or Imidicloprid, a systemic. I would be very suspicious of using this toxic chemical. Happy Gardening. ep