Gummy Stem Blight
Stagonosporopsis cucurbitacearum (Didymella bryoniae)
Fungus
Leaves
Stems
Fruit
Overview
A serious fungal disease of cucurbits causing leaf spots, stem cankers with amber gummy exudate, and fruit rot. Particularly damaging to watermelons, cantaloupes, and cucumbers.
Symptoms
Circular, tan to brown leaf spots. Water-soaked, cracked stem lesions that exude amber, gummy material. Crown rot at the soil line. Fruit rot (black rot) with dark, sunken lesions. Vine collapse.
Environmental Conditions
Humid
Prevention
Use disease-free seed. Rotate cucurbits on a 2-3 year cycle. Avoid overhead irrigation. Remove crop debris. Ensure good air circulation. Hot water seed treatment.
Management
Apply chlorothalonil or copper fungicides. Remove infected vines. Improve air circulation. Avoid wounding stems. Destroy crop residues after harvest.