ESSENTIAL OILS OF PRIPRIOCA AND PIMENTA ROSA IN MYCELIAL GROWTH AND DEVELOPMENT OF SCLERODES OF Sclerotinia sclerotiorum

The fungus Sclerotinia sclerotiorum is considered one the most important pathogens in the world and is distributed in all producing regions, be they temperate, subtropical or tropical. Their control through cultural practices and use of fungicides, often with little efficiency. The objective of this work was to evaluate the effect of essential oils of Pimenta rosa (Schinus terebinthifolius) and Priprioca (Cyperus articulatus L.) under mycelial growth and development of S. sclerotiorum as an alternative form of control. The work was carried out during the year 2018, in phytopathology laboratory of UTFPR- Dois Vizinhos. The essential oils obtained by steam trapping in Clevenger-type equipment, at a concentration of 15μL, were applied on autoclaved filter paper (1cm2) and attached to the top lid of the Petri® plate. A mycelial disc (7mm) of S. sclerotiorum pathogen was placed in the center of the plate containing BDA (Potato-Dextrose and Agar) medium. For control, distilled water was used instead of the oil. The plates were kept in B.O.D. type incubation chamber for 10 days at a temperature of 25 ° C ± 1 ° C and a 12 hour photoperiod, and mycelial growth was evaluated daily and at the end of the experiment the formation of sclerotia. The data measured were MCM, Mycelial Growth Index, Mycelial Growth Rate Index, Number of Formed Sclerodes and Mean Sclerode Size. The experimental design was completely randomized, and the experimental unit was composed of a plate with five replicates. The essential oils of pimenta rosa had a mycelial growth of 6.14 cm2, while the essential oil of priprioca showed growth of 6.36 cm2, the two were statistically different from the control (7.32 cm2). The mycelial growth index of the pimenta rosa, priprioca and control oils were 1.11, 1.15 and 1.33 respectively. For mycelial growth rate, the indices did not differ between the treatments. As for sclerotia production, the essential oil of priprioca presented a reduction of 10% in the production compared to control, while the oil of pimenta rosa had a 53% increase in the amount of sclerodia produced. Regarding the size, the essential oils did not present significant differences. It was concluded that the essential oils of pimenta rosa and priprioca presented positive results in relation the mycelial growth, but in the production of sclerotia, the essential oil of priprioca presented better results when compared with the control, making the best treatment.