Investigations of Rhizoctonia solani in potatoes depending on the sowing time

The fungus's sclerotia ("pockmarks"), which lie on the surface of the tuber, reduce the phytosanitary quality of seed potatoes and cause marketing problems for washed potatoes intended for consumption. The pathogen is transmitted both via the seed potatoes and the soil. Disease occurrence is particularly promoted by delayed emergence of the crop due to unfavorable weather conditions (low air and soil temperatures). An overly short potato crop rotation, the inclusion of forage crops or clover grass, and a predominant supply of organic fertilizers, primarily straw-based farmyard manure, increase the risk of infestation.
Unlike other diseases, there is no way to control Rhizoctonia solani during the growing season. Countermeasures therefore consist of suitable agronomic measures, such as an optimal potato crop rotation, a reduction in organic fertilizers, and choosing an optimal sowing time when the soil temperature allows for rapid emergence of the planted tubers. Seed treatment in combination with optimal application technology also reduces infestation and thus secures yields as well as significantly increasing the quality of the harvested product.