New data on the survival of tomato pathogens after overwintering

Tomato ( Solanum lycopersicum L.) is affected by various pathogens of fungal and fungal-like diseases. Soil containing pathogens in the arable layer or on infected plant residue is usually considered the main source of infection. Although it is known that the survival time of plant pathogens in natural conditions differs, precise information on the degree of survival after overwintering on trellises and garter materials is rather scarce. In this work, the overwintering survival of pathogens on trellises and garter materials used for cultivation of a number of tomato varieties and hybrids has been proven for the first time. The survival of tomato pathogens after overwintering and storage in the open air for one year and two years was assessed. Field research was carried out at the site of the Garden non profit partnership «Agronom», created by employees of the Moscow Timiryazev Agricultural Academy and located near the Dubna River in the Kimry district of the Tver region, where in the growing season of 2021 year on a tomato plantation of 50 plants, diseases at significant level were noted. The trellises (dry miskantus stems and wooden slats with pieces of twine attached to them) released after the tomato harvest were placed in the open air from August 2021 to July 18, 2023. After a year and two years of overwintering, some of its were taken as samples for laboratory analysis. For microscopic analysis, scrapings and washes were used from the trellises, sections of twine as a garter material, adhesive tape and electrical tape fastening the trellises. After a year storage of trellises and garter material in the open air,, viable propagules of tomato leaf mold agent Cladosporium fulvum Cooke, septoria leaf spot agent Septoria lycopersici Speg., early blight agent Alternaria alternata Sorauer, oospores of late blight agent Phytophthora infestans (Mont.) de Bary, molds Chaetomium globosum Kunze and Aspergillus Micheli, as well as agents from genera Fusarium Link, Phoma (Saccardo) and Helminthosporium Link were detected. It should be noted that during this period, about 690 mm of precipitation fell, and the ninimum winter temperature reached -25 °C. After two year storage in the open air at analogical trellises Cladosporium fulvum conidia were found on all 14 trellises, and only two trellises revealed single oospores of Phytophthora infestans . All detected conidia and oospores looked viable. It should also be noted that during this two year period, about 1,400 mm of precipitation fell, and the minimum winter temperature reached -27 °C. Thus, our observations indicate successful mass overwintering and one-year preservation of 9 tomato pathogens on trellis and garter material, as well as two-year overwintering and preservation of 2 of them. The experimental data obtained on the persistence of infection on trellises and garters are important for understanding and developing recommendations for the preparation and cultivation of various varieties and the prevention of tomato infection in the Tver and Moscow regions, as well as in other regions with similar agroclimatic conditions. Within the framework of the practical significance of the study, it is necessary to give a recommendation to destroy trellises with garter material after harvesting tomatoes or to thoroughly disinfect them.