Conidia of Metarhizium flavoviride were suspended in oil formulations and received fatty and other acids before germination. This was done by the acids being added either to the conidial suspensions before inoculation onto agar plates or directly into the agar before the conidia were applied. Certain acids of chain lengths C10 and below, including lactic, salicylic, caprylic and capric acids produced significant inhibition of germination when added to the oil formulations. When incorporated into the agar, all acids of C10 and below were inhibitory, with the exception of sebacic and succinic acids. Sebacic acid (a C10 saturated dicarboyxlic acid) and all the longer chain fatty acids sampled produced no inhibition of germination, either when added to the formulation or the agar. Tests were carried out on a sample of conidia which showed no germination; a few acids stimulated some germination. These included sebacic acid and longer chain fatty acids such as stearic and (inconsistently) lauric acids. Conidia from a long term storage experiment showed increased germination on the addition of stearic and/or lauric acids. The inhibitory effect of capric acid on germination was overcome by a 4–15 times higher concentration of stearic acid.