Modelling fungal spore dispersal using <i>Neonectria ditissima</i>

Abstract

Neonectria ditissima is the causal organism of European canker in apple Conidia are formed in sporodochia in canker lesions and released during rain The splash pattern of conidia was monitored in four directions from a central inoculum source held at approximately 17 m height using vertical and horizontal rain traps trap plants and petroleumjellycoated glass slides during simulated rain events Nonlinear models were fitted to the conidia count data to estimate the proportion of inoculum exceeding any distance from the inoculum source When fitted to horizontal rain trap data the model suggested that half of all spores splashed beyond 042 m from the inoculum source and 4 travelled over 2 m Conidia were observed at a greater distance from the inoculum source using rain traps than glass slides In a separate set of experiments water was dropped in single droplets from various heights onto either a sealed surface or bare soil and watersensitive paper was used to estimate droplet sizes and dispersal (height and distance) Water droplets were found to splash up to 120 cm outwards and 60 cm upwards Smaller droplets travelled further than larger droplets