Pumpkin Stems Rotting

Disease Identification

• Pumpkins are susceptible to the gummy stem blight disease, a fungal infection caused by Didymella bryoniae/Phoma cucubitacearun. Other host plants include a variety of cucurbits including cucumber, squash and watermelons. Gummy stem blight is a serious pumpkin disease and infects plant at any stage of growth.

Symptoms

• Early symptoms include lesions on all plant areas except the roots. Stem lesions are water soaked and tan colored. As the disease progresses, these lesions exude gummy, reddish-to-black colored beads and the entire stem gradually decays. Symptoms on foliage are scattered, irregularly shaped spots. A yellow hallo forms around the spots, and there are cracks within the discoloration after the leaves dry. The disease is called black rot when it affects the fruit.

Favorable Conditions

• The soilborne fungus persists for extended periods in the ground and debris from infected older plants. It may spread to new plants in the area. Splashing water from overhead irrigation or rain spreads the spores. Optimal moisture and temperature between 61 and 74 degree promotes the disease. Prolonged presence of moisture on the foliage also favors the disease's spread. The fruit is usually infected from diseased, dying flowers or wounds inflicted during harvest.

Control

• Use disease-resistant seeds produced in dry, western regions. Practice crop rotation with noncucurbit vegetables and plow crop debris deeply after harvest, diffusing any persisting fungi in the soil. Recommended chemicals for control include mancozeb or chlorothalonil. Do not keep seeds from plants grown in areas with known presence of the disorder.