|VEGA-GALVEZ, ANTONIO - University Of La Serena
Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2016
Publication Date: 7/11/2016
Citation: Bilbao-Sainz, C., Chiou, B., Valenzuela-Medina, D., Imam, S.H., Orts, W.J., Vega-Galvez, A. 2016. Biopolymer films to control fusarium dry rot and their application to preserve potato tubers. Journal of Applied Polymer Science. 133:44017. https://doi.org/10.1002/app.44017.
Interpretive Summary: Potato tubers are usually coated with fungicide during storage to prevent infections. Some of these fungicides are coated in powder form, which leads to exposure by workers applying the coatings. This creates possible health concerns for the workers. Also, direct coating of the tubers might not be the most efficient method for fungicide application since sufficient amounts need to be applied on the tuber surface to ensure effectiveness. Consequently, over application might occur and results in some fungicide loss. One method to reduce fungicide loss is by incorporating it in a biopolymer film. The total fungicide amount incorporated in the films would be lower than those used in direct applications. In this study, we incorporated a common fungicide, fludioxonil, into sodium alginate and chitosan films. We then examined the antifungal properties of the films against two fungi, Fusarium solani, which causes Fusarium dry rot, and Phitophtora infestans, which causes potato late blight. These are two of the most common and destructive diseases of cultivated potatoes in the US and worldwide. Sodium alginate and chitosan films containing fludioxonil were effective against Fusarium solani for 8 days. Also, chitosan films containing fludioxonil were effective against Phitophtora infestans for 31 days. However, sodium alginate films were not effective against Phitophtora infestans.
Technical Abstract: Films were cast using sodium alginate, high molecular weight (HMW) chitosan and low molecular weight (LMW) chitosan as film forming biopolymers. Fludioxonil was used as fungicide. Thermal stability and water sorption properties of the films were examined. The effect of films on the fungi area growth of Fusarium solani and Phitophtora infestans was evaluated over time. Results showed that chitosan films were more thermally stable and less hydrophillic than alginate films. In addition, films containing fludioxonil successfully limited the growth of Fusarium solani for 8 days. No differences in anti-fungal properties were observed due to the film forming biopolymer used. LMW chitosan films were the most effective against Phitophtora infestans. LMW Chitosan containing fludioxonil limited fungal growth even after 31 days. In comparison, the sodium alginate films containing fludioxonil showed no antifungal properties against Phitophtora infestans.