Control of Ergot (Claviceps purpurea (Fr) Tul.) with New Pesticides

Abstract

The studies were carried out at the Federal Agrarian Scientific Center of the Northeast during the period from 2013 to 2017 and in 2019. Model experiments tested seventeen chemical and biological preparations for the ability to limit the germination of sclerotia of the fungus Claviceps purpurea Fr. Tul. The dynamics of growth of mycelium of the fungus Spacelia segetum Lev. have been studied in paired microbial associations (in vitro). The experiments had three replications, and in vitro studies had four replications. The highest biological efficacy was found in the new Turion fungicide, which averaged 90% for 3 years. The Bunker, Dividend Star, and Vitazit preparations showed quite high efficacy (70–80%). In these variants, sclerotia that preserved their viability formed 2–6 stroma with fruiting bodies, while they formed 3–27 stroma in the control variant. Among biofungicides, Pseudobacterine had the highest efficacy (69%). Despite the same active ingredient, all preparations were found to significantly differ in antibiotic properties; therefore, the work with fungicides is individual. A series of laboratory experiments revealed a marked and prolonged antagonism in the biosystem Spacelia segetum–Streptomyces hygroscopicum, strain А-4. The sterile area around S. hygroscopicum averaged 1.95 cm² for all isolates. It was maintained after 14 days of incubation of the test culture, which makes this strain promising for the construction of a new target biopreparation. Weak inhibition in growth of S. segetum colonies was found in the presence of the fungus Acremoniella occulta and the bacterium Flavobacterium fulvii, strain L-30.