Bacterial Wilt
Disease · Commonly affects: Cucumber, Muskmelon (cantaloupe), Summer squash, Pumpkin, Winter squash, Gourds
Bacterial wilt is a fast-moving vascular disease of cucumber-family crops caused by the bacterium Erwinia tracheiphila, which overwinters inside cucumber beetles and is spread when those beetles feed on plants. It matters to home gardeners because a single infected plant can collapse within days and there is no cure once symptoms show, so success depends almost entirely on prevention.
How to identify it
Watch for individual leaves that wilt and dry during the heat of the day while the rest of the plant still looks healthy, with the wilting then spreading vine by vine until the whole plant caves in. A simple field test helps confirm it: cut through a wilted stem near the base, touch the two cut ends together, and slowly pull them apart, and if fine sticky white threads of ooze stretch between them, bacterial wilt is the likely cause. Striped or spotted cucumber beetles feeding on the leaves and flowers are the other telltale sign.
Damage
The bacteria multiply inside the xylem, the tissue that carries water up from the roots, and their sticky masses plug these vessels so the plant can no longer move water to its leaves. This starves the plant of moisture even in moist soil, causing progressive wilting and death that often strikes just as the vines begin to set fruit, wiping out the crop.
Prevention
Rotate cucurbits to a different part of the garden each year and clear out old vines and plant debris at the end of the season so overwintering beetles have fewer places to shelter. Favor less susceptible crops and varieties where you can, since cucumbers and muskmelons are hit hardest while many squash and most watermelons hold up better. Keep plants growing strongly with even watering, healthy soil rich in organic matter, and generous spacing for airflow, because vigorous plants better shrug off early beetle feeding.
How to manage it
Because the disease rides in on cucumber beetles, control focuses on the insects: cover young plants with floating row covers from transplanting until flowering, then lift the covers so bees can pollinate or hand-pollinate underneath. Handpick beetles in the cool early morning when they are sluggish, set out yellow sticky traps, and protect natural enemies such as soldier beetles, tachinid flies, and ground beetles by not spraying broadly. Pull and destroy any plant showing wilt right away so beetles cannot pick up bacteria and carry them to healthy vines, and water at the base to keep plants unstressed.
General guidance for US home gardens, focused on prevention and non-chemical control. For a confirmed diagnosis and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.