In vivo application of garlic extracts in combination with clove oil to prevent postharvest decay caused by Botrytis cinerea, Penicillium expansum and Neofabraea alba on apples

• Garlic extracts and clove oil are effective in vivo antifungals when used against the pathogens Botrytis cinerea and Penicillium expansum.
• Garlic extract effectively reduced lesion diameter when applied curatively on all apple cultivars.
• Curative application of extracts was better than protective application of extracts onto the three apple cultivars.
• Garlic extracts and clove oil was not effective for the control of Neofabraea alba on apples.

Curative and protective applications of garlic extracts and clove oil directly or through volatile exposure were tested in vivo for potential to inhibit decay caused by postharvest pathogens Botrytis cinerea, Penicillium expansum and Neofabraea alba on three apple cultivars, ‘Granny Smith’, ‘Golden Delicious’ and ‘Pink Lady’. Curative application of the extracts by direct exposure proved to be more effective than a protective application for decay management of B. cinerea and P. expansum on all three cultivars. The efficacy of garlic extracts and clove oil, individually, as well as a combination treatment, did not differ significantly (P < 0.05) from each other; however, all treatments significantly (P ≤ 0.05) reduced decay when compared to the control treatments. Direct exposure of fruit that were artificially inoculated with N. alba, to the extracts, did not result in any inhibition compared to the control treatments. Exposure of inoculated fruit to the volatiles of the extracts did not inhibit postharvest decay on any of the apple cultivars, and in some cases, resulted in increased lesion diameters. This study demonstrated that the curative application of garlic extracts has the potential to reduce postharvest decay caused by B. cinerea and P. expansum, when applied directly to the fruit.