Even though data showed no significant differences between the garlic extracts and clove oil treatments, the garlic extract at 40% and 50% elicited a slightly smaller lesion diameter compared to the 40% garlic extract + 1% clove oil treatment, for the curative application indicating that the garlic treatments alone performed better at reducing pathogen development.
The effect of protective treatments differed depending on the cultivar with 1% clove oil + 40% garlic extract giving significantly better control of B. cinerea. With this treatment there was no significant difference observed for the cultivars tested. A significant reduction in lesion diameter relative to the control is noted on all three cultivars ( Fig. 1).
Curative application of garlic extracts and clove oil by direct exposure of the pathogen to the extract showed a significant treatment and cultivar interaction (P ≤ 0.05) for the control of P. expansum ( Fig. 2). All treatments significantly reduced the lesion diameter on all three cultivars compared to the control. Although not significantly different to other treatments such as 40% and 50% garlic extract and 1% clove oil, the combination treatment worked best to inhibit growth of P. expansum on ‘Granny Smith’ and ‘Golden Delicious’ apples.