EFFECTS OF THYME (ZAATAR) ESSENTIAL OIL AND SOME CHEMICAL COMPOUNDS IN THE CONTROL OF CITRUS BACTERIAL CANKER IN IRAN

• Published in: Journal of plant pathology Vol. 91; no. 3; pp. 691 - 696
• Main Authors: Samavi, S., Hassanzadeh, N., Faghihi, M.M., Danesh, Y. Rezaee
• Format: Journal Article
• Language: English
• Published: An International Journal of the Italian Phytopathological Society 01.11.2009
• Subjects: Bacteria; Chemical compounds; Citrus; Crop protection; Essential oils; Infections; Lesions; Phytopathology; Plant diseases; Plants; Seedlings; Thyme; Thymus
• ISSN: 1125-4653; 2239-7264

The efficiency of two novel compounds, thyme essential oil (TEO) produced from zaatar (Zataria multiflora) and Nanosilver (NS), as well as some commonly used chemicals were evaluated against citrus bacterial canker using detached-leaf assays in the laboratory and whole seedlings in the greenhouse. Mexican lime seedlings were used for detached leaf assays. Treatments included 0.3% copper oxychloride (COC), 1.5% Bordeaux mixture (BO), 0.3% COC+0.04% Mancozeb (MZ), 1.5% BO+0.04% MZ, TEO at 10⁻² dilution, three concentrations of NS (100, 150 and 200 ppm) and 100 ppm Streptomycin (S). The BO+MZ, COC+MZ and TEO treatments were found most effective based on mean number of lesions and type of symptoms on detached leaves. Greenhouse experiments were done to assess the protective effects of the same treatments. Nine-month-old seedlings were sprayed with the treatments and after 24h, the young leaves were inoculated with bacterial suspension by pin-prick. The number of lesions on treated leaves was counted 14 days after inoculation and rates of infection were measured. Results showed that all treatments were significantly different at P<0.01%. The best results were obtained with BO+MZ and TEO at 10⁻² dilution, with infection inhibition of 78.44% and 69.78%, respectively. Moreover, COC+MZ, BO, S and COC alone reduced the disease by 60.15%, 55.15%, 45.78%, and 41.09%, respectively. The least effective compound was 100 ppm NS which only reduced the infection by 15%.