Potato skins covered in scabs ruin their market appeal - how do you prevent and control scab disease?

    Potato common scab means the potato skin is covered with scabs of varying size and depth. Once common scab develops, although the lesions are limited to the potato's cortex, the affected potatoes do not keep well and look unsightly. Infected potatoes are poor in quality and low in commercial value.

Potato common scab

    Causes of common scab: first, seed potatoes were planted without being soaked and disinfected; second, the field could not avoid continuous cropping with potatoes, radishes, carrots, sugar beets and other crops that had previously suffered from common scab; third, the tuber bulking period coincided with high temperatures and drought.

    Control measures:

    First, choose disease-resistant varieties, such as Yushu No. 1, Luyin No. 1, Yushu No. 1, Chunshu No. 1, Taishan No. 1, Baifeng, Wulibai and other varieties.

    Second, practice crop rotation. First, fields where common scab has occurred should be rotated for more than 2 years; second, improve the field's irrigation facilities to ensure adequate water during the tuber-setting period and keep the field moist; third, choose slightly acidic soil for planting.

    Third, apply organic fertilizer. In fields with residual pathogens, consistently applying organic fertilizer and bio-organic fertilizer can suppress soil-borne pathogens well.

    Fourth, chemical control. ① Use a 0.2% formalin (formaldehyde) solution to soak washed potato seed pieces for 2 hours, or soak them in a 0.1% hydroquinone (chemically pure) aqueous solution for half an hour, then take them out, dry them and plant; ② in diseased fields, use 40% quintozene powder for soil disinfection, at 1.2-2 jin per mu; ③ in the early stage of the disease, spray with a 1000-fold dilution of 65% mancozeb wettable powder, once every 7-10 days, for a total of 2-3 sprays.