Penicillium verrucosum is one of the main producers of ochratoxin A (OA) in agricultural commodities. To forecast the risk of OA
contamination, there is a need to improve our knowledge on the ecology of P. verrucosum in the field. Dilution plating on ‘dichloran
yeast extract sucrose 18% glycerol agar’ (DYSG) offers a simple and very sensitive method of detecting P. verrucosum propagules in
soil. The properties of DYSG are illustrated in a suspension mixture experiment and confirmed in a soil mixture experiment. In the
latter, P. verrucosum could be detected in conidial concentrations below 200 colony forming units (cfu) g−1 soil even when it
constituted no more than 0·3% of the cfu. Furthermore, the DYSG method can be used to estimate the abundance of P. verrucosum
propagules in soil with good precision. In some of the analysed cases, however, it was necessary to use appropriate mathematical
models to treat results with high numbers of cfu on the Petri dishes.