Inhibition of conidium germination and mycelial growth of Botrytis cinerea by natural products

Using in vitro tests, 21 oil extracts were assessed at 0.1. 1.0 and 10% concentrations for effects on conidium germination, germtube elongation and mycelial growth in Botrytis cinerea. Reduction (P less than or equal to 0.05) of conidium germination and germtube length was achieved at 0.1% concentration with extracts of thyme R (Thymus capitatus) (100% and 100% respectively), clove (Syzygium aromaticum) (67% and 93% respectively) and Australian minttree (Prostanthera rotundifolia) (65% and 65% respectively). Thyme R oil and Trichoderma harzianum metabolites 6-pentyl-alpha-pyrone (6-PAP) and a 6-PAP derivative, gave the greatest inhibition of mycelial growth of the extracts tested at 10% concentration.