NON-CHEMICAL APPROACHES TO POSTHARVEST DISEASE CONTROL
The past ten years has seen a steady increase in the interest of finding alternatives to the use of synthetic fungicides for postharvest disease control. In particular, this has led to considerable research on the use of microbial antagonists as protective agents in much the same way as packing houses use synthetic fungicides for disease control. Biological products such as Aspire, BioSave, and Yield Plus, based on either yeast or bacteria, are now available in the marketplace and several new products are in various stages of development. The success of these products, however, remains limited. This is for several reasons, among which are the variability experienced in the efficacy of these products, and the lack of understanding how to adapt “biological approaches” to a commercial setting. Researchers and industry have responded by trying to find “super” antagonists, which may result in the use of particular strains for particular commodities or even cultivars, finding additives that may enhance the performance of the selected antagonists, or integrating the use of their products with other “physical” treatments that induce resistance in the selected commodity. Examples of these approaches are: using combinations of different antagonists; combining antagonists with chitosan; combining antagonists with additives such as sodium bicarbonate, calcium chloride, EDTA, potassium sorbate, calcium propionate, etc.; and, pre-treatment of produce with UV-C light or heat. Gamma-irradiation of produce has also been demonstrated as a feasible approach, especially with concerns about food contamination, but has met with consumer resistance. Genetic engineering of microbial antagonists to enhance performance, or of the commodity itself to enhance disease resistance is also being explored but may meet with consumer resistance. While it is not possible to determine which of these approaches will lead to widespread, commercial application, it is apparent that the interest in reducing the use of synthetic chemicals has led to the discovery of creative alternatives that have strong potential. Successful adaptation of these alternatives may require a more integrated and holistic understanding of postharvest disease management.
Wisniewski, M., Wilson, C., El Ghaouth, A. and Droby, S. (2001). NON-CHEMICAL APPROACHES TO POSTHARVEST DISEASE CONTROL. Acta Hortic. 553, 407-412
heat treatments, salt solutions, induced resistance, microbial antagonists, yeast, bacteria, chitosan.