Cucumber Beetles

• Cucumber beetles eat the leaves off cucumber plants. However, these pests do their worst damage by transmitting bacteria that causes wilt in cucumber plants. Cucumber plants exhibit signs of bacterial wilt less than one week after infection, according to North Dakota State University. Gardeners may see their cucumber plants rapidly wilt and die. There is no cure for bacterial wilt; therefore, entire crops may be lost. Drenching the soil with pesticide right after transplanting cucumber plants may offer season-long treatment, according to the University of Kentucky. Foliar treatments may be used when cucumber beetle populations are high.
  
  

Aphids

• Aphids suck the sap out of cucumber plants' leaves. Their damage causes leaves to yellow, curl and defoliate. Moreover, aphids leave behind a sticky substance called honeydew. Fungal spores that cause diseases such as sooty mold get stuck on the honeydew and create more problems for the plant. A cucumber plant covered in sooty mold has a difficult time photosynthesizing. Gardeners can treat their aphid problem with insecticidal soap. Avoid using insecticidal soap on days when air temperatures exceed 90 degrees Fahrenheit. Also refrain from spraying pesticides when bees are pollinating your flowers so that you don't kill beneficial insects.
  
  

Spider Mites

• Spider mites severely damage cucumber plants during hot, dry weather conditions, according to Clemson University. Mites feed off leaves, which causes small red, yellow or brown spots to appear on the surface. Left untreated, spider mites can stunt a cucumber plant's growth. Apply an insecticidal soap to your cucumber plants to get rid of these pests. Space your insecticidal soap applications five days apart. For minor infestations, you can knock the spider mites off your plants with a spray of water.
  
  

Pickle Worms

• Pickle worms eat cucumbers, leaves and stems off plants. When pickle worms are half grown, they burrow into cucumbers and eat the vegetable from the inside out, according to North Carolina State University. Also, they leave behind excrement. Cucumbers left untreated may soon become riddled with pickle worm holes. Treat your cucumber plants as soon as you notice signs of a pickle worm infestation. Keep an eye on your cucumber garden in the spring for the moth that lays these eggs.