Dispersal of the entomopathogen Hirsutella cryptosclerotium by simulated rain

Fernández García, E.; Fitt, B.D.L.

Dispersal of the entomopathogen Hirsutella cryptosclerotium by simulated rain

1993

Fernández García, E. | Fitt, B.D.L.

When simulated rain fell 11 m down a rain tower onto sporulating cultures or spore suspensions of Hirsutella cryptosclerotium, a pathogen of the mealybug Rastrococcus invadens, large numbers of spores and mycelial fragments were dispersed in splash droplets. Negative exponential models fitted the decreases in numbers of spores, spore-carrying droplets, and mycelium-carrying droplets with distance, and regressions of log (number) on distance accounted for more than 65% of the variance. About 50% of the droplets carrying inoculum were deposited within 10 cm of the source and none were collected beyond 40 cm. Sizes of spore-carrying and mycelium-carrying droplets did not decrease greatly with increasing distance from the source but the number of spores per droplet decreased rapidly. When the distribution of inoculum-carrying droplets with droplet size was examined, the greatest proportions of spore-carrying droplets and mycelium-carrying droplets were, respectively, in the range 200-400 and 600-800 micrometer, and mycelium-carrying droplets were generally larger than spore-carrying droplets.

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