Occurrence and Control of Potato Black Shank Disease

Symptom

Potato black shank is a bacterial disease that infects vascular tissues and can infect potato stems and tubers. The disease can occur from seed potato germination to the later growth stage, and it is the most popular in the seedling stage. Most of the diseased plants droop under water, the leaf color does not change, the whole plant wilts, and most of the black shins soften and rot. The color of the disease is yellowish brown, light brown or dark brown, light green and so on. The vascular bundles in the stem and the vascular bundles of the underground stem changed color basically into a ring-shaped stem and the connection between the base of the stem and the sweet potato blackened at first, and then developed near the ground to form a black shin. When the humidity is high, the black shin can rise to 3.3 to 6.6 centimeters above the ground, and some have bacterial pus on the surface. In the adult stage, the black shank is mostly dark brown to dark black, and the pith of the underground stem is often empty. The pathogenic bacteria can send along the stolon to the new tuber, and the symptoms of the black shin also develop to the new potato, making the navel dark brown. Seriously ill potato pieces, the epidermis darkened, dull. There was no significant difference between lightly susceptible potato and healthy potato.

The pathogen of potato black shank belongs to Eucalyptus, which is short rod-shaped. The pathogen can adapt to a wide range of temperature, growing well in the range of 10-38 ℃, the most suitable for 25-27 ℃, and losing its ability to live at 45 ℃.

Disease regularity: the disease is mainly carried by diseased potato, which is transmitted to seed potato through cutting knife, causing mother potato to rot and entering the aboveground stem of plant from mother potato through vascular bundle and pith. In the later stage, the pathogen was introduced into the new tuber from the aboveground stem through the stolon. During storage, diseased potato contact, bacteria can be transmitted through wounds or lenticels, transmission quickly. The diseased potatoes and remnants left in the soil are also the sources of primary infection. Diseased plants in the field can be transmitted by insects and running water, and then infect healthy plants from the wound.

The occurrence of black shank disease is closely related to temperature. Rain Water has a lot of disease in low-lying land. During the storage period and in the cellar, poor ventilation, high temperature and humidity, bacteria spread quickly through the wound and lenticels, which is easy to cause rotten cellar.

Prevention and cure measures

1. Disease-resistant varieties were selected from some of the more disease-resistant or disease-tolerant varieties in various regions.

two。 The establishment of disease-free seed field was selected by single plant, bud planting or whole potato sowing.

3. To promote sprouting and drying seeds and eliminate diseased potatoes, soil trench film can be used to accelerate sprouting and drying seeds. The specific method is as follows: about 25 days before sowing, dig a soil ditch with a depth of 0.5 meters, a width of 1.0 to 1.3 meters, and a length according to the number of seed potatoes. The bottom of the ditch was covered with grass 10.0cm 13.3cm thick, covered with 3 layers of seed potato, covered with plastic film and kept under 17mm 25 ℃ for about 7 days. when the young buds were driven out of the matchstick head, the seeds were exposed in the daytime, covered with grass curtain to prevent freezing at night, and the diseased potatoes could be completely eliminated by navel inspection.

4. Plant ash mixed with seeds can promote the suberization of the wound, and sow immediately after mixing.

5. Dig out the diseased plants and remove the diseased remains in the field, reasonably rotate the stubble and avoid continuous cropping.

6. Early sowing should pay attention to drainage, reduce soil moisture, select fields with high dryness and good drainage, increase ground temperature, promote early emergence, and reduce the infection and epidemic of black shank disease.

7. Field chemical control of foliar spraying 0.1% copper sulfate solution or copper hydroxide or copper hydroxide can significantly reduce black shank disease.