Post-harvest fog treatment of apples: deposition patterns and control of Phlyctaena vagabunda and superficial scald

Abstract

An experimental facility was constructed for post-harvest fog treatment of apple fruits stored in pallet-boxes. Its performance was tested by determining the distribution and effectiveness of fog application of the fungicide thiabendazole (TBZ) on wet and dry apples cv. ‘Abbondanza’. Deposition was greater on the upper (stalk end) than the lower (calyx end) part of the fruit but uniform between fruits in the pallet-box. The fog treatment was more effective against Phlyctaena vagabunda than the dip treatment; neither length of treatment nor pre-wetting of fruits substantially affected the distribution of TBZ fog deposit. The distribution and performance of the anti-oxidant diphenylamine (DPA) as fog on ‘Stayman red’ apples was also tested. As with TBZ deposit on cv. ‘Abbondanza’, the DPA deposit was significantly greater on the top than the bottom of the fruit. Inversion of the pallet-box during fog treatment resulted in a more uniform deposit on fruit. Fog- and dip-treatment with DPA were equally effective in preventing superficial scald.