Tip drought is a disease that has been causing severe damages to eucalyptus trees, resulting in canker along the branches. The aim of the present study was to evaluate the effect of fungicides and plant extracts on the control of Botryosphaeria ribis. The in vitro test of fungicides was completely randomized with eight treatments: carbendazim, chlorothalonil, difenoconazole, picoxystrobin + ciproconazol, ciproconazol, azoxystrobin, picoxystrobin and control, four doses: 1 µg/mL, 10 µg/mL, 100 µg/mL and 1000 µg/mL, with five replicates. After homogenization of the medium, they were plateds, recultured in a disk with culture medium containing the pathogen and kept in BOD at 25 ° C for five days. The evaluation was done by daily measuring the mycelium radial growth in centimeters. The experimental design of chemical control in the field was in 5x3 factorial arrangement, five fungicides and three application methods, with four replicates. Four applications were done with fifteen-day intervals. Treatments were: 1. azoxystrobin, 2. carbendazim, 3. chlorothalonil + thiophanate-methyl, 4. difenoconazole and 5. control. Simultaneously evaluations were done following a scale from 1 to 6, conform the intensity of symptoms. The experimental design in vitro using plant extracts was in 5x4, factorial arrangement, with three replicates. The evaluated treatments were extracts from: a thousand leaves sao caetano melon, eucalyptus, alcohol and control, at the concentrations of 5, 10, 15 and 20%. The extracts and the alcohol were mixed with previously autoclaved culture medium, which was then plated in Petri dishes. The evaluation was done by daily measuring the mycelium radial growth in centimeters. In the test with seedlings the experimental design was in 2x2x4, factorial arrangement, and two cultivars were used besides two treatment modes (preventive and curative) and four control products (são caetano melon extract, C. citriodora extract, alcohol and water). The pathogen was inoculated into the stem of seedlings. Applications and evaluations were done weekly. The evaluation was done by counting the diseased plants. The active ingredient carbendazin showed the best results in vitro statistically differing from the other treatments according to Tukey's test at 1% probability, followed by chlorothalonil and difenoconazole. All active ingredients were superior to the controls. In the field, azoxystrobin was superior to the remaining treatments and there was no significant difference between application methods. In vitro the extracts from thousand leaves, melon and eucalyptus did not differ according to Tukey's test at 5% probability. Alcohol led to the greatest mycelial growth inhibition and differed significantly from the other treatments. The concentrations 10, 15 and 20% extracts did not differ but were superior to the concentration of 5%. In the test with seedlings, the preventive application was superior to healing application, while alcohol and C. citriodora extract did not differ, but were superior to the sao caetano melon extract. All products were superior to control.
Corymbia citriodora; Dothyorella sp.; chemical control; control using plant extracts
