Figure 3.

Penetration frequency of the nonadapted powdery mildew Erysiphe cichoracearum on Vitis vinifera following treatment with increasing concentrations of cytochalasin E (A), brefeldin A (B) and wortmannin (C). Successful penetration was scored by the presence/absence of a haustorium. Each data point ± standard deviation is based on three biological replicates (leaves) on which a minimum of 100 germinated conidia were scored. Asterisks indicate a significant difference from the negative dimethylsulphoxide (DMSO) control (P < 0.01; Student's t‐test).