Figure 1. Gummy stem blight on watermelon. Image provided by C. McGregor
Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae), Stagonosporopsis citrulli, and Stagonosporopsis caricae
Gummy stem blight affects the stems and leaves of cucurbit crops but watermelon is particularly susceptible. On occasion, it can also infect the fruits of squash, which is known as black rot of cucurbits. Infected leaves develop dark brown lesions that are typically located on the leaf margins and the petioles, lesions eventually coalesce and cause defoliation of the plant. Infected stems may split and become covered in ooze, giving the characteristic gummy appearance. Severe infections can result in plant death.
Plant Disease Management Reports
- Evaluation of DMI fungicides and Miravis Prime to manage gummy stem blight caused by a tebuconazole-resistant isolate of Stagonosporopsis citrulli on fall watermelon, 2022. PDMR 17: V072.
Keinath, A. P., DuBose, V. B., Mothersbaugh, A. C., and Zardus, S. H. - Evaluation of DMI fungicides rotated with mancozeb to manage gummy stem blight on fall watermelon, 2020. PDMR 17: V069. Keinath, A. P., DuBose, V. B., and Zardus, S. H.
- Evaluation of fungicides management for watermelon gummy stem blight, Kinston 2022. PDMR 17:V098
Rosado-Rivera Y.I., Quesada-Ocampo L.M. - Evaluation of fungicides for control of gummy stem blight on watermelon, Kinston, NC 2020. PDMR 17:V170
Rosado-Rivera Y.I., Adams L.M., Quesada-Ocampo L.M.
Factsheets:
- Gummy Stem Blight of Cucurbits, NC State University, 2013
More information about Gummy stem blight
Figure 2. Stem with fungal fruiting bodies known as pycnidia. Shawn Butler, NCSU Plant Disease Insect Clinic.
Figure 3. Necrotic, brown spots on leaf margins. Dr. Lina Quesada, NCSU Vegetable Pathology Lab
