What to Do When Muskmelon Gets Gummy Stem Blight? A Detailed Guide to Prevention and Control Methods

Muskmelon, the fruit of a Cucurbitaceae plant, has fleshy fruit with multiple locules and numerous seeds, much like a berry, but the receptacle and exocarp of these fruits fuse together, often forming a thick outer rind, and in classification they are specifically called “pepos”, of which muskmelon is a typical example.

Symptoms after muskmelon gets gummy stem blight:

It mainly harms the vines, and both the main vine and side vines are susceptible, with the affected parts often being near the base of the plant's stem and vines. The lesions initially appear near the nodes as pale yellow, oil-soaked spots, slightly sunken, elliptical to spindle-shaped; the diseased area cracks easily and secretes a yellowish-brown gummy substance that turns reddish-brown or black and lumpy after drying. In the later stage of growth the diseased area gradually dries out and becomes sunken, appearing grayish-white, with small black dots scattered on the surface. Leaves and fruits can also be affected; leaf lesions are dark brown, round or irregular, with obvious concentric rings, and small black dots appear on old lesions at the leaf margins, while diseased leaves dry out and crack in a star shape. On fruits, water-soaked spots appear initially, and the center of the lesion turns into a brown necrotic spot, cracking in a star shape and causing the melon to rot; the disease strikes violently and spreads rapidly from fruit enlargement to maturity, and in severe cases can cause total crop loss. 

Transmission routes and conditions for disease onset:

This disease is caused by infection with Mycosphaerella melonis. The pathogen can overwinter on diseased plant debris and in the soil, and the seed surface can also carry the pathogen. The pathogen spreads by wind and rain. It can invade through the internodes of the stem, the leaves, the hydathodes at the leaf margins, and wounds. High temperature and high humidity, dense leaves and vines, poor ventilation, fertilizer deficiency, and weak plant growth all make the disease more likely, and it is more severe in continuous-cropping fields and low-lying fields; wounds caused by fertilization and vine training make it easy for the pathogen to infect.

Prevention and control methods after muskmelon gets gummy stem blight:

Implement a 2 to 3 year crop rotation. Apply fully decomposed organic fertilizer, and pay attention to a reasonable balance of nitrogen, phosphorus, and potassium fertilizers. Disinfect seeds before sowing. Scald dry seeds with 70°C hot water for 10 minutes, with the water volume being 3 times the seed volume, stirring constantly while scalding so the seeds are heated evenly. Chemical control. In the early stage of disease, use Domaike at 1500 times dilution, 50% thiophanate-methyl wettable powder at 500 times dilution, or 25% carbendazim wettable powder at 800 times dilution, or 70% chlorothalonil wettable powder at 600 times dilution. Or use Ridomil plus chlorothalonil mixed to a paste and apply it to the stems.