symptom
Also known as strawberry leaf spot. It mainly damages leaves, mostly on old leaves. The periphery of the lesion is purple-brown, and the center fades to gray-white or gray-brown, with a diameter of 1.5-2.5 mm, with purple-red ring patterns, a white powdery mold layer on the surface of the lesion, and small black spots afterward, that is, the ascus of the fungus.
Pathogen
Ramularia tulasnei, called Dura column septum is an asexual ascomycete of the fungal kingdom. Conidiophores branched in clusters or unbranched, basal subunits undeveloped. Conidia cylindrical, colorless unit cells, or with 1-2 septa.
Transmission routes and disease conditions
Overwinter with mycelia on the dead leaf lesions, produce conidia in the next spring for initial infection, and later produce conidia for re-infection in the diseased part. The optimum temperature for germ growth is 18-22°C, and growth retardation occurs when the temperature is lower than 7°C or higher than 23°C.
Prevention method
(1) Select high-quality varieties such as Gorella, Induka, Mingbao, etc.
(2) Clean up the fields in time after harvesting, and burn the damaged leaves.
(3) Eliminate diseased seedlings during planting.
(4) Spray 500 times solution of 50% succinic acid copper wettable powder, 2000 times solution of 10% difenoconazole microemulsion, 600 times solution of 62.25% Dai Nitribacter wettable powder, 75% Cyananthraquinone WP 500-1000 times liquid. Once every 7-10 days, spray 3 times in total.
