Abstract

Damping-off disease, caused by Rhizoctonia solani, leads to severe worldwide economic losses in many important crops. The current strategies to control this disease are inadequate. This study addresses the possibility of using ZnO nanoparticles (NPs) and two cultivars of sunflower to be employed in control strategies. The ZnO NPs were significantly (P=0.01) more inhibitory to R. solani growth at high concentrations than lower treatments indicating a dose-dependent effect. This effect was found to be fungistatic when fungal inoculum was transferred to standard medium after challenging with the ZnO NPs. Additionally, the two cultivars of sunflower tested were found to be susceptible to pathogen R. solani showing a high percentage of damping-off incidence and severity of symptoms. Although, most treatments of ZnO nanoparticles applied did not significantly reduce the damping-off incidence, the disease severity was significantly reduced. This was particularly clear when the seedlings of the two sunflower cultivars were sprayed with ZnO NPs two days prior to planting the best suppression ranging from 100 to 53.12% in Euro flower cv. and from 95.31 to 54.68% in Flame cv. The reported findings in this study suggest that the application of the ZnO NPs together with current control approaches could improve the health of field grown sunflower crops and therefore the overall yield.