Study of the influence of limestone ameliorants on the germination of zoosporangia of the pathogen of potato cancer in the foci of the disease

Goal. To determine the effects of limestone meliorants of raw grind and phosphorite flour on the germination of zoosporangia of the pathogen of Cynchytrium endobioticum (Schilb.) Perc. in the foci of the disease. Methods. Laboratory (study of the effectiveness of limestone meliorants against the pathogen of potato cancer), field (study of the effectiveness of the action of reclamation against the pathogen in the field), phytopathological (detection and identification of zoosporangia of the cancer pathogen before and after processing), mathematical (processing of research results). They determined the soil pH by methodological recommendations [28], and technical efficiency according to the methodology [29]. Experiments were carried out in 2021–2023 on a variety of potatoes Poliska rozheva susceptible to cancer. Results. At the use of raw grind (in doses of 0.5; 1.0; 1.5 and 2.0 t/ha), the soil pH increased from slightly acid (6.2) to alkaline (8.6). At the same time, the germination of zoosporangia of the pathogen of potato cancer in the foci of the disease decreased from 46.3 to 37.9 pcs./g of soil, which was 4.7–11.3%. With the increase in the soil pH from 6.2 to 7.8 (slightly alkaline) with the use of limestone meliorant of phosphorite flour, zoosporangia germination decreased from 46.3 to 41.9 pcs./g of soil (8.2–10.1%). The use of both meliorants (raw grind and phosphorite flour) contributed to the increase of soil pH to 8.6 and a decrease in the germination of zoosporangia of the pathogen from 46.3 to 29.7 pcs./g of soil (17.1–30.4%). Conclusions. Laboratory and field studies fixed that in cancer foci at the use of limestone meliorants, the acidity of the soil was reduced. This contributed to greater efficiency (19.5–35.9%) of soil purification from zoosporangia of the cancer pathogen, depending on the used doses of meliorants. With the use of safe substances, it was possible to reduce the infectious load of the cancer pathogen in the foci of the disease. This environmentally friendly measure of the control of the potato cancer pathogen to limit the spread of the pathogen is proposed to be introduced in the foci of the disease to improve their phytosanitary condition.