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Effect of simulated rainfall events on spore dispersal and spore stocks in three tropical pathosystems

Savary S., Janeau J.L., Allorent D., Escalante M., Avelino J., Willocquet L.. 2004. Phytopathology, 94 (6) : S92. Annual Meeting of the American Phytopathological Society, 2004-07-31/2004-08-04, Anaheim (Etats-Unis).

Tap and puff followed by dry spore transport (TP), spore dislodging from lesion and drip (DR) along plant tissues, and splash dispersal (SP) were monitored under simulated rain conditions in coffee rust, peanut rust and bean angular leaf spot. All three processes were triggered by rainfall events in the three diseases. Results suggested that TP predominates in low intensity and short rainfalls, whereas SP remains stable in importance under high intensity, long rainfalls. Any rainfall event strongly depleted (20-40%) stocks of spores in a diseased canopy rendering the event of major epidemiological importance when repletion is slow. Medium-duration and intensity rainfalls (e.g., 5-10 mn, 30 mm.h-1) generated large flows of spores to the soil (10-40% of stocks). For biotrophic pathogens, such events are thus strong epidemiological penalties if they do not lead to efficient disease spread. (Texte intégral)

Mots-clés : phaeoisariopsis; puccinia arachidis; hemileia vastatrix; Épidémiologie; spore fongique; pluie; maladie fongique; rouille; phaseolus; arachis hypogaea; coffea

Thématique : Maladies des plantes

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