Strictly guard against diseases when introducing sweet potato

At present, sweet potato cultivation in our province is expanding into non-traditional growing areas. In these areas, sweet potato storage and seed preservation techniques are not up to standard, and when the storage pits are opened in spring, the tubers are severely rotten, so the supply of seed potatoes cannot be guaranteed. Some sweet potato farmers have to introduce seed from other places, which increases costs. Because farmers lack knowledge about introducing seed, they often bring in diseased seed potatoes when introducing varieties, causing outbreaks of pests and diseases. Many sweet potato pests and diseases are spread by the tubers, and introducing seed has become the main route for spreading pests and diseases. The main pests and diseases spread through seed potatoes include root rot, black spot disease, stem nematode disease, and the sweet potato weevil. In recent years, because northern Jiangsu blindly introduced seed from diseased areas, sweet potato stem nematode disease became widespread over large areas, and root rot also caused damage in certain regions.

Stem nematode disease is also called pith-heart disease. After the tuber is infected, the inside becomes pithy while the outer skin remains intact, so its appearance is the same as a healthy tuber, but it has no use value. Once stem nematode disease and root rot contaminate the soil, they are difficult to eradicate, and the diseases accumulate year by year, seriously affecting sweet potato production. Therefore, the first issue to pay attention to when introducing sweet potato is not to introduce diseased tubers. In addition, attention must also be paid to the different uses of sweet potato and the adaptability of varieties.

1. Do not introduce seed from diseased areas. At present, the main sweet potato diseases in northern sweet potato areas are stem nematode disease and root rot. Both diseases reduce sweet potato yields to varying degrees, and in severe cases can even cause total crop failure. Before introducing seed, first investigate the source area, and only introduce seed after confirming there is no disease, so as to avoid bringing in diseased seed potatoes.

2. Introduce seed according to use. Sweet potato types can be divided into starch-processing type, edible baking type, and so on. Among them, the starch-processing type requires that the variety's dry matter rate not be too low; generally, the dry matter rate of starch-type varieties is above 28%, and the flesh color is best white or pale yellow. Edible baking-type varieties require the tuber flesh to be yellow or orange-red, and the dry matter rate can be appropriately relaxed.

3. Pay attention to variety adaptability. Sweet potato varieties have special adaptability to soil quality, cultivation methods, climate, and other factors. Planting can be expanded on the basis of demonstration trials; do not blindly introduce large quantities.