Goji berries are renowned medicinal herbs with a long cultivation history in China. Effective pest and disease control are essential management practices when cultivating goji berries. So, what's the best treatment for the common Cercospora leaf spot affecting goji berries? Let's find out.
How to Treat Goji Berry Cercospora Leaf Spot?
Symptoms of Goji Berry Cercospora Leaf Spot
Goji berry Cercospora leaf spot primarily affects the leaves and can also harm the fruits. Affected leaves develop circular or nearly circular lesions with brown edges and grayish-white centers. Black mold-like structures, the reproductive bodies of the pathogens, appear on the underside of the leaves. Surrounding leaf areas may turn yellow, and severe cases can lead to fruit drop.
Pattern of Goji Berry Cercospora Leaf Spot Outbreaks
Goji berry Cercospora leaf spot is caused by the fungus Cercospora lycii Ell. et Halst., which spreads primarily through wind and rain. Factors such as high temperatures, excessive rainfall, high soil moisture, humid air, soil nutrient deficiency, and weakened tree vigor contribute to its occurrence.
Treatment Methods for Goji Berry Cercospora Leaf Spot
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Variety Selection: Choose high-quality goji berry varieties such as Ningqi 1, Baoqi 1, and Rongqi 1, which exhibit strong growth and resistance to disease.
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Orchard Sanitation: Clean the orchard thoroughly after leaf fall in autumn, including pruning to remove diseased leaves and fruits. Dispose of them away from the orchard to minimize the spread of pathogens.
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Enhanced Management: Implement rigorous field management practices, including additional phosphorus and calcium fertilization, to boost plant resistance.
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Optimal Planting Density: Plant goji berries in rows with a spacing of 30 cm between rows and 10-15 cm between plants to promote robust growth without excessive vigor.
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Chemical Treatments: For prevention, begin spraying 80% mancozeb manganese zinc wettable powder in June to prevent disease occurrence. For control, apply fungicides such as methyl thiophanate, propiconazole, tebuconazole, or epoxiconazole at the onset of symptoms. Spray every 10-15 days for 3-4 times for better control.
In conclusion, as summer approaches, the warm and humid climate conditions favor the occurrence of goji berry Cercospora leaf spot, posing a threat to both leaves and fruits. Therefore, to safeguard goji berry yields, growers should take preventive measures in advance.
