Celery Phyllosticta leaf spot
symptom
Also known as celery or celery leaf spot. Mainly damages leaves. The disease of old leaves usually begins at the tip or edge of the leaf. Small water-soaked chlorotic spots appear at first, and then gradually expand into irregular or semicircular large spots. The center is off-white, and the edge is greenish-brown. When the humidity is high, the back of the lesion Fruiting bodies grow, and in the later stage, small black dots are densely packed on the lesions, which are the pycnidia of pathogenic bacteria. Severe lesions are contiguous, causing the leaves to dry up, causing serious damage to the shed, and the production has a tendency to expand.
pathogen
Phyllosticta apii Halst, also known as Phyllosticta apii Halst, belongs to the fungus kingdom Ascomycota anamorphic Phyllostachys genus.
Transmission routes and disease conditions
The fungus mainly overwinters on diseased debris or seeds with pycnidia. Planting diseased seeds the following year can cause disease in celery. The conidia produced by the diseased part are spread by wind and rain, and the spores germinate to produce germ tubes and invade directly from the host epidermis. From July to August, there are many years of continuous rain, concentrated and large rainfall, or the disease of planting diseased seedlings is severe.
Prevention method
①Choose different varieties. Carry out 2 to 3 years of crop rotation.
②Cultivate in high borders and open drainage ditches to avoid water accumulation in furrows. Covered with a shade net.
③ Spray 70% propineb wettable powder 500 times liquid or 20% propiconazole microemulsion 2000 times liquid, 70% metiram water dispersible granule 600 times liquid or 50% thiophanate-methyl suspension times liquid, 55% flusilazole · carbendazim wettable powder 900 times liquid, once every 7-10 days, continuous control 2-3 times.
