Germination and survival of <i>Neofusicoccum luteum</i> after different storage treatments

Abstract

Neofusicoccum luteum is a widespread fungal pathogen of grapevines The germination and survival of N luteum conidia was tested following storage at different temperatures and times The conidia (10⁵/ ml water) were incubated at 2 8 and 2023C (ambient temperature) for 0 2 4 24 48 72 h 1 2 and 3 weeks The conidial suspensions were then microscopically examined for conidial germination adjusted to 10²/ml and 100 l spread onto PDA to check for viability At ambient temperature 67 of conidia germinated after 2 h and 74 after 48 h When held at 8C 23 of conidia germinated after 24 h and the proportion gradually increased up to 33 in 2 weeks while at 2C 4 had germinated after 48 h increasing to 19 in 3 weeks The maximum periods of viability of stored conidia (as determined by their ability to form colonies on PDA) was 48 h for ambient temperature 2 weeks for 8C and 3 weeks for 2C This research showed that N luteum can germinate quickly at normal summer temperatures as well as at low winter temperatures so can infect trimming wounds during summer and pruning wounds during winter