Short-term effects of soil solarization in suppressing Calonectria microsclerotia

Calonectria species have beenreported as devastating pathogens mostly on horticulturaland forest crops worldwide. Since these pathogensrepresent a serious threat for the nurseryproduction, the aim of this study was to investigate onthe short-term potential of soil solarization for eradicatingCalonectria microsclerotia.Methods Twenty Calonectria isolates collected inItaly from different hosts and locations were identifiedby using DNA sequencing of β-tubulin. The effect ofthermal regimes and innovative solarizing films on thesoil survival of Calonectria microsclerotia was evaluatedthrough time at different sampling periods ingrowth chamber and greenhouse experiments.Results Eleven and nine isolates were identified asCalonectria pauciramosa and Calonectria polizzii,respectively. No viable Calonectria inoculum wasrecovered after 12 days from all solarized plots insideethylene-tetrafluoroethylene (ETFE) greenhouse andat 15-cm depth from solarized plots inside ethylenevinyl-acetate (EVA) greenhouse. Under EVA cover,solarization killed C. pauciramosa microsclerotiawithin 9 and 17 d at 15- and 30-cm depths in soil,respectively, whereas no viable inoculum was retrievedwithin 6 and 12 days from solarized plotsinside ETFE greenhouse.Conclusions This paper demonstrates that short-termsoil solarization is effective for Calonectria microsclerotiasuppression in nurseries, and shows thatETFE film as well as other innovative materials couldimprove this technique.