Use of a Complexation of Tebuconazole with β-Cyclodextrin for Controlling Foot and Crown Rot of Durum Wheat Incited by Fusarium culmorum

The methodology for the inclusion of tebuconazole (TBC) in β-cyclodextrin (βCD), spectroscopic characterization of the inclusion complex, and its activity for the control of a major soilborne disease of wheat caused by Fusarium culmorum are reported. Controlled release measured by chemical shift of the diagnostic protons H3 and H5 of βCD confirmed stability of the complex at the solid state and in aqueous solution. Greenhouse and field experiments were conducted on durum wheat (Triticum durum cv. Prometeo) sown in substrate or in soil artificially infested with a virulent strain of F. culmorum. The inclusion complex βCD−TBC, applied as seed dressing in combination or not with carboxymethylcellulose, reduced the disease incidence caused by F. culmorum and improved grain yield, showing effects that were generally comparable to those observed upon application of a commercial formulation of TBC. In the field experiment, only seed treatment with the inclusion complex βCD−TBC allowed yield that was not different from that obtained from the uninoculated control. These results prove that by the use of the βCD−TBC complex it is possible to obtain release of TBC and bioavailabilty of the fungicide without compromising its effectiveness. Keywords: Tebuconazole; β-cyclodextrin; inclusion complex; wheat; crown and foot rot; Fusarium culmorum