Short-term effects of soil solarization in suppressing Calonectria pauciramosa and C. polizzii microsclerotia

Background and aims Calonectria species have been reported as devastating pathogens mostly on horticultural and forest crops worldwide. Since these pathogens represent a serious threat for the nursery production, the aim of this study was to investigate on the short-term potential of soil solarization for eradicating Calonectria microsclerotia. Methods Twenty Calonectria isolates collected in Italy from different hosts and locations were identified by using DNA sequencing of ?-tubulin. The effect of thermal regimes and innovative solarizing films on the soil survival of Calonectria microsclerotia was evaluated through time at different sampling periods in growth chamber and greenhouse experiments. Results Eleven and nine isolates were identified as Calonectria pauciramosa and Calonectria polizzii, respectively. No viable Calonectria inoculum was recovered after 12 days from all solarized plots inside ethylene-tetrafluoroethylene (ETFE) greenhouse and at 15-cm depth from solarized plots inside ethylene-vinyl-acetate (EVA) greenhouse. Under EVA cover, solarization killed C. pauciramosa microsclerotia within 9 and 17 d at 15- and 30-cm depths in soil, respectively, whereas no viable inoculum was retrieved within 6 and 12 days from solarized plots inside ETFE greenhouse. Conclusions This paper demonstrates that short-term soil solarization is effective for Calonectria microsclerotia suppression in nurseries, and shows that ETFE film as well as other innovative materials could improve this technique.