Athogenic properties of pathogens and the damage of straw- berry varieties by mycoses of the root system

Abstract

   Fungal isolates isolated from garden strawberry plants Fusarium semitectum Berk. Et Ravenel and Verticillium albo-atrum Reinke et Berth proved to be pathogenic. Under field conditions, artificial inoculation with these isolates increased the development of verticillium disease to 24.0-57.0 % and the development of fusarium disease to 26.0-31.0 %, which significantly exceeded the growth of root rot in control at the level of 2.0-2.2 %. Inhibition of the above-ground system length in infected plants reached 6.5-30.5 % relative to the control. In a laboratory experiment, the presence of pathogenic properties in an isolate of the fungus Fusarium solani (Mart.) Sacc., also isolated from strawberry plants, was proved. Artificial inoculation caused a decrease in the length of the above-ground system by 33.2 %, the number of new leaves by 53.8%, a reduction in the size of the roots by 43.9 %, and increased rhizome necrosis by 3.2 times relative to the control. The general condition of strawberry plants in the control was satisfactory by 3.2 points. The negative effect of the phytopathogen in variants with inoculation was manifested in a decrease in the state of plants to a level of 1.3-1.4 points. According to the results of a 3-year observation, the varieties Alexandrina, Festivalnaya Romashka, and Solnechnaya Polyanka showed relative resistance to fusarium disease of strawberries (the development of the disease on average over three years ranged from 2.8 to 5.7 %, with 11.3 % in the standard variety Yunia Smaids). Varieties Feya, hybrid Lutova, Aleksandrina, Festivalnaya Romashka, Solnechnaya Polyanka, Festivalnaya, and Anastasia had relative resistance to verticillium disease (the development of the disease on average over three years ranged from 0 to 1.8 %, with 8.9 % for the standard).