Chemical protection of potatoes from fungal diseases, taking into account the stability of the variety

Abstract

In the conditions of the Moscow region in 2019-2022 the effectiveness of funicides of new chemical classes in the potato protection system against rhizoctoniosis, late blight and alternariosis was studied, taking into account the different resistance of varieties (Gulliver, Grant, Sante) to diseases. Potato tubers were treated with the preparation Idikum, SC before planting, its biological effectiveness in reducing the incidence of rhizoctoniosis in the full germination phase was 76.7-95.7 %. It was found that the effectiveness of the preparation depended on the degree of disease development, the stability of the variety and the phase of crop development. In addition, when etching the planting material with Idikum, SC, there was no population of rhizoctosis sclerotia and the spread of dry rot on tubers of the new yield significantly reduced (1.6-5.0 times) compared to the control. The proposed scheme of potato protection in conditions of epiphytotic development of late blight and early blight based on combined chemicals Metaxil, SP, Inside, SC with contact fungicides Raek, CE, Talent, SC, Tirada, SC showed high efficiency in reducing harmfulness of the diseases, which allowed to extend the growing season of plants, to ensure a higher yield of potatoes, its marketability and quality. The use of preparations provided an increase in yield by 36.3-47.5 %, depending on the prevailing weather conditions of the growing season and on the variety in relation to the control (without treatment). It has been established that the biological effectiveness of the protection scheme in reducing the degree of late blight and early blight increased from susceptible to relatively stable varieties and, accordingly, this trend continued with an increase in yield. Higher increases were obtained on unstable varieties Gulliver and Sante (10.6-13.5 t /ha, or 45.7-56.0 %), lower – on the relatively stable variety Grand (7.8 t/ha, or 36.0 %). The contribution of the application of the protection scheme to the overall variation of gross and marketable potato yields was 76.5-81.0 %, gene-type - 7.9-12.5 %, the interaction of these factors – 3.7-4.7 %.