Bacterial wilt is caused by bacteria that invade the plant’s water-conducting tissue, preventing water from moving normally through the plant. Affected plants may wilt rapidly even when the soil has plenty of moisture, and severely infected plants can collapse and die.

In cucumbers and other cucurbits, bacterial wilt is commonly caused by Erwinia tracheiphila and spread primarily by striped and spotted cucumber beetles. The beetles acquire the bacteria while feeding on infected plants and introduce them into healthy plants through feeding wounds.

How to Fix It

There is no cure for an infected plant. Remove and dispose of badly affected plants to reduce sources of bacteria for cucumber beetles feeding in the garden.

The most effective control is preventing cucumber beetle feeding, particularly while plants are young. Use floating row cover or insect netting early in the season, sealing the edges carefully. Remove the cover when flowering begins if bees need access for pollination. Control weeds and volunteer cucurbits that can provide food and shelter for beetles.

There is no reliable biological treatment that cures bacterial wilt inside an infected plant. Biological approaches aimed at reducing cucumber beetles may help indirectly, but for the home gardener, physical exclusion and early beetle control are the most dependable strategies.