60 Phytopathogenic Mollicutes, Vol. 3(1), June 2013 Perspectives for the management of phytoplasma diseases through induced resistance: what can we expect from resistance inducers? Phytopathogenic Mollicutes Vol. 3(1), June 2013, 60-62 Perspectives for the management of phytoplasma diseases through induced resistance: what can we expect from resistance inducers? Gianfranco Romanazzi Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University. Via Brecce Bianche, 60131 Ancona, Italy Received: April 26, 2013; Accepted: May 19, 2013 Abstract Because there are no effective means to control the phytoplasma-associated diseases when they are established, an effective management could be the application of abiotic or biotic resistance inducers. Among the latter some arbuscular mycorrhizal fungi and plant-growth-promoting rhizobacteria were tested together with several chemical compounds able to start a reaction of the plant. Recovered plants following application of resistance inducers showed qualitative and quantitative production parameters similar to those of healthy plants. The possibility to contain phytoplasma diseases within an integrated approach that include, together with the applied control measures based on clean propagating materials, vector control and weed management, a stimulation of plant defences can become practically important for growers. Keywords: phytoplasma, recovery, induced resistance, management Phytoplasma disease can cause severe losses to a long list of crops since no protocols to control phytoplasma diseases are available, and preventive measures rely on the use of healthy propagating materials and in the control of insect vectors. One of the few possibilities to reduce disease symptoms is the use of resistance inducers (Romanazzi et al. , 2009a). Resistance inducers, called also elicitors, can be of abiotic or biotic nature and challenge the plant, leading to a reaction, often linked to the production of antimicrobial compounds and/or the elicitation of plant defense mechanisms. The treatment with resistance inducers can be successful in i) decreasing the number of infected plants, ii) reducing the severity of disease symptoms, and iii) delaying the appearance of disease symptoms. Abiotic resistance inducers are usually chemical compounds able to start a reaction of the plant. The most common elicitors used to control phytoplasma Corresponding author e-mail : (g.romanazzi@univpm.it) doi : 10.5958/j.2249-4669.2.1.001 diseases are: benzothiadiazole (BTH), Phosetyl-Al, prohexadione calcium, indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), chitosan, salicylic acid (SA), mixture of glutathione and oligosaccharines (GOs). Most studies were carried out on experimental hosts infected with a phytoplasma, e.g. Arabidopsis thaliana challenged with X-disease phytoplasma (Bressan and Purcell, 2005), Catharanthus roseus inoculated with chrysanthemum yellows (CY) or elm yellows (EY) phytoplasmas (Prati et al. , 2004; Chiesa et al. , 2007), or with aster yellows (AY), EY or “stolbur” (Curkovic Perica, 2008; Leljak-Levanic et al. , 2010). SA was applied in crops as tomatoes infected potato purple top phytoplasma (Wu et al. , 2012). Trials on woody crops infected by phytoplasmas can be more difficult because it is not easy to find a high number of plants that after application allow getting significant differences in recovery induction. First evidence of resistance inducer application was obtained in Sardinia Scientific Correspondence