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Citrus canker disease is one of the most devastating diseases that attacks citrus, especially limes in the Southern parts of Iran, and is caused by Xanthomonas citri subsp. citri (Xcc). The efficacy of several formulations of copper compounds including Bordeaux mixture, copper oxychloride and copper sulphate in controlling Xcc in Key lime was estimated in vitro and in planta using artificial inoculation. Specific primers were used to detect copper‐resistant genes copA, copB and copL in 30 isolates of Xcc. The copA and copL genes were present in all isolates, and copB was detected only in 6 strains. In this study, we observed a very good in vitro growth inhibition activity of copper compounds against Xcc pathotype A. S14 strain (pathotype A*) was the sole isolate that grew on media amended with 2/4 mM of Bordeaux mixture, copper oxychloride and copper sulphate. All other strains (pathotype A) failed to grow on media amended with this concentration. Bordeaux mixture exhibited high efficacy in controlling Xcc in both conditions. However, there were no significant differences in the efficacy of copper oxychloride and copper sulphate at 1.2 mM concentration in planta. A significantly minimum canker necrotic spot and highest disease control was achieved with Bordeaux mixture and copper oxychloride. There was a significant difference in disease severity of the type strain LMG9322 (pathotype A) and Xcc strain S14 (pathotype A*). Our experiments showed that Bordeaux mixture exhibited satisfactory efficacy in controlling the causal agent of citrus canker.

Effects of Pseudomonas fluorescens L. (jimsonweed) (Pf) isolate and the two plant extracts, Datura stramonium and Myrtus communis, were investigated on hatching and juvenile (J2s) mortality of Meloidogyne javanica(Tylenchida: Heteroderidae) under laboratory conditions. After determining the values of LC30, LC50, and LC70 of each extract, four leaf stage seedlings of tomato were treated by 20 ml of Pf suspension at a concentration of 108 CFU/ml, using a soil drenching method. After 1 week, the tested plants were inoculated by 4000 eggs and (J2s) of M. javanica and simultaneously were treated by 100 ml of the selected concentrations of D. stramonium (1.1, 1.4, and 1.8%) and M. communis (1.8, 3 and 5.2%), as soil drench. Results showed that a combination of Pf and the leaf extract, D. stramonium at the rate of 1.8% or M. communis at the rate of 5.2%, respectively, reduced the number of eggs per root system and the reproduction factor by 68 and 45%, the number of galls by 64 and 33%, and the number of egg masses by 65 and 43%, than the control. In conclusion, combination of Pf and D. stramonium at the rate of 1.8% or M. communis at the rate of 5.2% can significantly reduce the damage of M. javanica on tomato, under greenhouse conditions.

The efficacy of single and combined application of Trichoderma harzianum and Pseudomonas fluorescens (CHA0) in the controlling of Meloidogyne javanica on tomato plants was evaluated under green house conditions. Seeds of the susceptible tomato cv. Early-Urbana were sown in clean plastic pots containing 1.5 kg steam sterilized soil. Four weeks after planting, the soil of each pot was infested with a suspension of 20 ml/kg soil of T. harzianum (106 spores/ ml) and a suspension of 15 ml/kg soil of P. fluorescens (CHA0) (108 CFU/ ml). Soil of other pots were infested with the two tested bio-agents together as a combined application. Seven days later, plants in all pots, except the controls, were inoculated with M. javanica at initial population densities of 1, 2 or 4 eggs/ cm3 soil. Sixty days after nematode inoculation, the parameters of plant growth and nematode reproduction were determined. Results showed that the nematode reproduction factor (Rf) on the plants infected with 1, 2 and 4 eggs/ cm3 decreased by 58, 63 and 31% after the single application of T. harzianum, 11, 33 and 12% after the single application of P. fluorescens (CHA0) and 43, 55 and 49% after the combined application of the bio-agents, respectively. Combined application of the two bio-agents was found to be the most effective in controlling the higher initial population density of the nematode (4 eggs/ cm3).

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