Determination of the optimum treatment strategy against the early blight of potato under epiphytotic conditions

• Main Authors: Kuznetsova, M. A., Denisenkov, I. A., Rogozhin, A. N., Smetanina, T. I., Demidova, V. N., Statsyuk, N. V.
• Format: Conference Proceeding
• Language: English
• Subjects: Efficiency; Epidemics; Flowering; Foliage; Fungicides; Harvesting; Late blight fungus; Outbreaks; Pesticides; Potatoes
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0068481

Early blight (EB) has become a growing problem for potato production in temperate zones of Europe and North America, since climate changes resulted in more frequent favorable conditions for its outbreaks. The use of well-timed fungicide programs including a rotation of fungicides with different modes of action is critical for the proper protection of potato crops. However, no information is available concerning the comparative efficiency of different recommended EB-specific fungicides and schemes of their use under epiphytotic conditions in Russia. Using artificial infection of potato field intended to provoke an EB outbreak, a comparative evaluation of 8 different EB-specific protection schemes was carried out. The tested fungicide products included mandipropamide+diphenoconazole (Revus Top), mancozeb (Penncozeb), and boscalid+pyraclostrobin (Signum). Late blight-specific treatments included into all protection schemes make it possible to evaluate the contribution of the EB infection on the foliage blight development and yield losses and to determine the biological efficiency of the tested fungicides in relation to the EB only. The calculated EB development levels in different experimental variants expressed via the Area Under Disease Progress Curves (AUDPC), varied from 50 to 980 (1670 for the control) with the corresponding biological efficiency varying between 41 and 97%. The best results were obtained for the protection scheme which included a triple consecutive treatment with different fungicides (Revus Top, Penncozeb, and Signum) applied between the flowering phase and 25 days prior to harvesting. In this case, the AUDPC value did not exceed 55, the biological efficiency reached 96%, the corresponding yield increase compared to the control was 15.4 t/ha (the total yield was 57.5 t/ha) and the fraction of marketable potatoes reached 95%. This treatment scheme can be recommended as the optimum strategy for the practical use, especially under epiphytotic conditions.