P&PDL Picture of the Week for
April 4, 2011

Bacterial wilt of cucumber and cantaloupe

Dan Egel, Extension Plant Pathologist-SWPAC, Purdue University

Cucumber and cantaloupe growers know the problem well. In May and June, as the plants begin to vine out, the leaves begin to wilt and the entire plant collapses (Figure 1). There may be other reasons why cucumber or cantaloupe plants wilt, so it is best to get an official diagnoses (instructions on submitting samples to the Plant and Pest Diagnostic Laboratory at Purdue University). You can also view a video that will help growers learn to recognize possible bacterial wilt symptoms

Bacterial wilt is caused by a bacterium that is spread from plant to plant by either the striped or spotted cucumber beetle (Figure 2). Any practice that reduces cucumber beetle feeding will also reduce the symptoms of bacterial wilt. Applications of an insecticide may help to lessen cucumber beetle feeding and therefore, bacterial wilt symptoms. Homeowners should look for an insecticide product that specifically lists cucumber beetles and carefully follow label instructions.Cucumber and cantaloupe plants will become less susceptible to bacterial wilt as the plants become larger. Insecticide treatments are not needed all season long. Row covers should help to keep the cucumber beetles from the plants, but be certain to remove the covers to allow flowers to be pollinated by bees.



Click image to enlarge

Figure 1. Bacterial wilt of cantaloupe is often observed early in the season causing plants to wilt and die.

Photos 2 A (striped) and B (spotted). The bacterium that causes bacterial wilt is spread from plant to plant by the striped (A) or the spotted (B) cucumber beetle.

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service