Symptom Identification and Integrated Control Methods for Gummy Stem Blight of Cucumber

Gummy stem blight of cucumber is a common fungal disease in cucumber production, mainly affecting stems and vines, leaves and fruit. In the early stage of the disease, oval or spindle-shaped lesions appear on the stems and vines, showing an oily appearance, and later gradually turn grayish-brown; the affected parts often crack and exude an amber-colored gelatinous substance, commonly known as gummosis. Leaf damage mostly starts from the leaf margins, forming yellow-brown V-shaped or nearly round large spots, with small black dots scattered on the lesions. Under humid conditions, the disease develops rapidly, and in severe cases the stems and vines dry up and the whole plant wilts and dies. The disease favors high temperature and high humidity, and cucumber fields with continuous cropping, poor drainage, overly dense planting, poor ventilation and light penetration, and excessive nitrogen fertilizer application often have more severe outbreaks. In protected cultivation, if ventilation is not timely and the humidity inside the greenhouse remains high for a long time, the disease is also easily induced and can become epidemic. Control should be based on agricultural measures: crop rotation with non-cucurbit crops, use of disease-free seeds with seed disinfection treatment, and timely removal of diseased plant residues from the field for destruction. At the same time, reasonable dense planting, enhanced ventilation to reduce humidity, balanced fertilization, and increased application of organic fertilizer and phosphorus and potassium fertilizer should be carried out to improve the plant's own disease resistance. In the early stage of the disease, chemical control should be applied promptly; sprays such as mancozeb, difenoconazole, and azoxystrobin can be used, and lesions on stems and vines can also be treated by smearing the affected parts with the solution. Spraying should be uniform and thorough, attention should be paid to rotating different types of pesticides, and several consecutive treatments are needed to effectively control the spread of the disease.