Bacterial Wilt
Erwinia tracheiphila
Overview
Bacterial wilt of cucurbits (Erwinia tracheiphila) is vectored by cucumber beetles that feed on leaves and deposit bacteria into the xylem. Plants wilt permanently within days once vessels clog - a classic sudden-death problem for squash, cucumber, and melon beds. Bacterial Wilt enters through wounds and natural openings, then rides water films, insects, and contaminated tools. Wet foliage and hail or pruning injuries often precede outbreaks. Causal agent: Erwinia tracheiphila. In regenerative gardens, prioritize sanitation, airflow, and unbroken soil cover over calendar spraying, and intervene early when symptoms appear.
Symptoms
Sudden wilting of a leaf or runner that does not recover overnight, then whole-plant collapse. Cut stems may show sticky white ooze that can string between fingers. Plants die quickly without the yellowing typical of nutrient stress. Compare several plants and note whether symptoms spread after rain, insect feeding, or wet foliage. Photograph undersides of leaves and cut stems when wilt is present to refine the diagnosis. Rule out simple drought, fertilizer burn, and herbicide drift before assuming a pathogen - abiotic injury often mimics disease.
Environmental Conditions
Variable
Prevention
Exclude beetles with floating row cover early. Control weeds that harbor beetles. Prefer less-preferred cultivars when known. Never compost wilted cucurbit vines with active ooze in cool piles - bag and discard. Mulch to reduce splash, clear season-end debris, and avoid working plants when wet. Design beds for airflow and diverse plantings that support beneficial insects without creating permanent humid pockets around susceptible crops.
Management
Pull and destroy infected plants immediately to reduce beetle pickup. There is no curative spray. Suppress cucumber beetles with row covers until bloom, sticky traps, and perimeter trap crops. Replant only after vector pressure drops. Prefer drip irrigation, morning watering, and open spacing so leaves dry quickly. Disinfect pruners between cuts on woody plants. Use copper, sulfur, or biological products only as labeled protectants when pressure is high - they rarely reverse advanced infections alone. Destroy (do not casually compost) highly infectious debris.