Potato tuber scab

The development of common scab depends on the weather, soil conditions, and compliance with agricultural practices for cultivating potatoes. Tubers affected by scab not only lose their presentation, but their taste deteriorates (the starch content decreases), and the amount of waste during cleaning increases. Such potatoes are stored worse: pathogens penetrate into the tubers through wounds and ulcers on the skin, causing various rots.

The pathogens “populate” the tubers in the first weeks of their development.Spots and sores on the skin quickly increase in size, cork and can form a continuous crust on the surface of the tuber. Scab infestation intensifies on light (sandy, sandy loam) soils that quickly overheat, as well as calcareous soils.

The latter circumstance is explained by the fact that in dry, hot conditions the activity of soil bacteria that can resist scab pathogens decreases.

Scab pathogens accumulate mainly in the soil and on post-harvest residues. This is why it is so important to observe crop rotation when growing potatoes. On seed tubers, if they are stored correctly, the infection almost does not persist.

Thin-skinned varieties are especially susceptible to this disease. Varieties

• Blue,
• Detskoselsky,
• Zhukovsky early

are resistant to common scab. And yet, prevention begins with seed material. Potatoes are considered suitable for planting if there are no more than two tubers per hundred that show signs of common scab.

Autumn (before storing) and spring sorting of potatoes helps to identify diseased tubers. Before planting, the seed material is treated with Prestige fungicide: 70-100 ml per liter of water, consumption per 100 kg of potatoes.

Before planting, potatoes are germinated for 20-25 days at a temperature of 16-20 degrees. Germination allows you to create a race in time (potatoes sprout faster), which, in combination with an early planting date, allows the plants to develop in a more favorable period and avoid mass damage to tubers by scab.

Potatoes are planted when the soil at a depth of 10-12 cm warms up to 6-8 degrees. It makes no sense to plant in colder soil: the tubers do not germinate for a long time, stolons with a large number of nodules appear on them, i.e. the potatoes grow.

In the southern regions, it is recommended to plant potatoes not in ridges, but in a well-leveled bed, planting the tubers to a depth of 8-10 cm. The soil in level beds remains moist longer, which helps the tubers to sprout together and form good roots. The row spacing is 60 cm, the distance between holes in a row is 25-35 cm. The larger the seed tubers, the less often they are planted.

Already in May, it is advisable to mulch the row spacing to avoid overdrying and overheating of the soil, which are favorable for the development of scab. For the same reason, you should avoid fertilizing potatoes with wood ash, which alkalizes the soil.