Comparison of B otrytis cinerea airborne inoculum progress curves from raspberry, strawberry and grape plantings

Airborne B otrytis cinerea conidia concentration was monitored using a new q PCR assay in strawberry, raspberry and grape plantings in 2010, 2011 and 2012. Airborne inoculum progress curves ( IPC s) were constructed and analysed using the maximum ACC ( Y max ), ACC during the flowering period ( Y f ), and area under the IPC ( AUIPC std ) and descriptors derived from fitting growth models. The structure of IPC s was examined by conducting multivariate principal component analyses. The dimensionality of the data was reduced to two principal components ( PC s) accounting for 86·12% of the variation. All descriptors derived from growth models were associated with PC 1 and descriptors derived directly from the data were associated with PC 2. Based on principal component analysis, the structure of the IPC s varied with the crop, with AUIPC std values of 28·18, 42·79 and 155·83 and Y f values of 53·58, 20·14 and 142·54 conidia m −3  h −1 in raspberry, strawberry and grape, respectively. Time to 50% of the maximum inoculum concentration was lower in raspberry and strawberry than in grape. The IPC s monitored in raspberry were characterized by narrow ranges for mean absolute rate (0·012–0·016) and AUIPC std (16·80–48·85), the IPC s monitored in strawberry were characterized by wide ranges for mean absolute rate (0·031–0·080) and AUIPC std (12·31–98·39), and the IPC s monitored in grape crops were characterized by a lower mean absolute rate (0·006–0·012) and a higher AUIPC std (50·95–335·14).