Efeito de óleos essenciais sobre a germinação miceliogênica e carpogênica de Sclerotinia sclerotiorum (Lib.) de Bary

Abstract

The Sclerotinia sclerotiorum is a plant pathogen that causes the disease known as rot esclereotinia, present in many cultures. In Brazil, the list of host species is quite extensive, including crops of great economic expansion such as soy, beans, potatoes, tomatoes and more. For further development of knowledge of pathogen biology, an important tool is the evaluation of the viability of sclerotia through miceliogênica and carpogenic germination. The objective was to verify the potential of essential oils on the miceliogênica and carpogenic germination of S. sclerotiorum. The treatments were constituted by treatments of volatilization and immersion 17 essential oils applied to the sclerotia. The viability of the sclerotia was carried out by induction of miceliogênica carpogenic and germination. The miceliogênica germination was done on PDA medium and incubation was performed in a growth chamber the BOD to 18° C and 12 hour of photoperiod. The evaluations of germination were performed at 24, 48, 72 and 96 hours after the start of incubation. The carpogenic germination was induced in sterilized soil and incubation was conducted in a growth chamber with temperature of 18° C ± 2° C, 12 hours of photoperiod and soil moisture 100% of field capacity. The experimental design was completely randomized with four replicates for both experiments. Each experiment consisted of a double factor, which are considered qualitative, with 19 levels. The obtained data were submitted to analysis of average by Scott Knott test at 5% error probability. The results show that essential oils that had fungicidal effect by inhibiting the miceliogênica germination of sclerotia in the treated effect are atermisia and melaleuca. And both effects treated and volatile was the laurel, lemon grass, cinnamon and guacatonga. To the carpogenic germination of sclerotia in emission of stems the tangerine, ginger and priprioca oils inhibited completely the stems germination in the treated effect. Already cinnamon, surinam cherry and guacatonga inhibited the germination in two effects. In the apothecia emission, thyme and pink pepper oils show fungicidal effect in the volatile effect. The laurel, tangerine, clove and ginger oils also inhibited the issuance of apothecia, but these in the treated effect. Oils were fungicides in two different effects were the pear orange, clove, eucalyptus, guava, lemon grass, priprioca, cinnamon, surinam cherry and guacatonga. The most part of essential oils were more effective than the witnesses in inhibiting carpogenic germination of sclerotia.