Induction of systemic acquired resistance for the integrated managementof TYLCD in greenhouse tomatoes

Abstract: The use of acibenzolar-S-methyl (ASM) for inducing systemic acquired resistance is arecommended practice for the management of several plant pathogens. During 2007-2008, threetrials were carried out in commercial greenhouses in southern Sardinia (Italy) to evaluate theeffects of this resistance elicitor on the spread of Tomato yellow leaf curl disease in protectedtomato crops. In keeping with an integrated approach to crop protection, the efficacy of ASMwas evaluated alone and in combination with non-woven row covers (NWRC) during the firstweeks of the cropping period, a tactic adopted in recent years by a considerable number ofgrowers on the Island. The results obtained in our experiments suggest that ASM may be asuitable means for TYLCD management. However its efficacy is strongly dependent on correctdosage and application frequency in relation to the actual dynamics of disease spread through thecrop. The most interesting results were achieved when moderate infection progression wastreated by integrating the use of non-woven fabric with early and frequent applications of ASMover an adequate period of time. The use of NWRC, by limiting disease pressure, creates morefavourable conditions for the deployment of effective plant defence responses. However, thedefinition of IP&DM strategy based on the combination of these two tactics requires carefulregulation of ASM applications not yet determined for TYLCD control.