EFFICIENCY OF FUNGICIDES IN THE SUPPRESSION OF Pseudoperonospora cubensis

Abstract

Pseudoperonospora cubensis is one of the most important cucumber diseases. Its continued appearance in most parts of Europe, Asia and the United States and its persistence represent a significant threat to the production of cucumbers around the world. Although the disease has been successfully suppressed for many years, severe epidemics have been reported since 2004, especially in the United States (Ivanović, M. et al. 2001). Whether this is the result of a change in the pathogen population or changes in the environment, it is currently unknown. The control of the Pseudoperonospora cubensis relies on the application of fungicide and the resistance of the host itself to the pathogen. Nonetheless, the resistance of Ps. Cubensis is recorded worldwide, and host resistance is no longer sufficient to control the disease as it once was possible. Additional costs on fungicides, along with the potential loss of yield and up to 100% caused by the Pseudoperonospora cubensis, endanger the long-term sustainability of cucumber production (Đurovka, 2001). Knowledge of Ps. cubensis, its epidemiology, the process of infection and genetics of the population is currently lacking, which is why it is necessary to encourage future efforts for the development of resistant sorts as well as fungicides in order to successfully combat Pseudoperonospora cubensis (Ivanović, et al. 2007). Researching this pathogen can help us understand it, and develop effective measures for diagnosing and suppressing Ps. cubensis. In addition to preventive measures in the protection of cucumbers against plant diseases, the efficiency of fungicides, which suppress Pseudoperonospora cubensis, is a limiting factor in cucumber production. Pesticides with the following active substances were used in the study: propineb, metalaxyl + mancozeb, metiram, dimethomorph + mancozeb, azoxystrobin, amethotradine + dimethomorph, azoxystrobin, fluazinam (Vojinović 2014, Vojinović 2015.). The efficiency of the tested fungicides was calculated according to Abbot's formula, and it is 92-97% (Table 1.).