Gummy Stem Blight of Cucurbits

Didymella bryoniae

Mycosphaerella melonis


A fungal disease that mainly affects stems but may also be on leaves and fruit. Water soaked areas appear on stem near the centre of the plant which may develop into light brown to whitish, sunken cankers with tiny black spore bodies. The cankers may split and exude a reddish, gummy sap. Girdled stems wilt and die. On leaves black spot may appear. On fruit, firm, black, sunken spots may occur.

Species Affected:

Cucumber, Marrow, Pumpkin, Rockmelon, Watermelon.

Watermelons are most susceptible followed by Rockmelons which usually only show slight symptoms. Cucumbers and Pumpkins may have blemished fruit in seasons particularly conducive to infection.


Favoured by moist conditions.

Carried on seed and plant debris from previous crops.

Spores are spread by wind.

Life Cycle:

Origin and History:



Management and Control:

Plant healthy seed.

Rotate crops with 3-4 years between successive Cucurbit crops.

If the disease is apparent in the crop, pick the fruit carefully and use it quickly.

Apply fungicides from the first sign of disease.

Related and Similar Species:




Collated by HerbiGuide. Phone 08 98444064 for more information.