symptom
Grape branch blight can attack branches, cobs, fruit grains, leaves and roots. When the branches are infected, brown water-soaked irregular lesions initially appear on the branches, and then expand to oblong or spindle-shaped stripes. The lesions are dark brown and there are small black spots on the lesions. The surface of the diseased branches is longitudinally cracked, and the phloem is peeled off, and the xylem is dark brown and necrotic, and the vascular bundles are browned; the tip of the young branch infected with the disease dies first, and then the whole branch dies.
pathogen
One is Pestalotia. The other is Pestalotio-psis Pseudomonas. At present, the genus Pseudomonas is identified in our country.
Transmission routes and disease conditions
The pathogen survives the winter as mycelium in diseased branches, leaves, fruit cobs and other diseased residues, and can also survive the winter as conidia on branches, buds and tendrils. When the temperature and humidity are suitable in the spring of the following year, conidia discs and conidia will be produced. Conidia spread by airflow, wind and rain, invade from host wounds, and begin to develop disease after 2 to 5 days of incubation.
Prevention method
(1) Remove the source of bacteria, and cut off the diseased branches when pruning in autumn.
(2) Strengthen the management of the orchard, cut off the auxiliary shoots, tendrils and leaves in time, and keep the surface of the shelf ventilated and light-transmitting.
(3) Chemical control. Spray 800 times liquid of 70% thiophanate-methyl wettable powder or 4000 times liquid of 37% difenoconazole water dispersible granule, or 8000 times liquid of 40% flusilazole EC before the onset of the disease, and use different agents after 10 days Spray again.
