38 research outputs found
Epidemiological characteristics of angular leaf spot of bean: a systems analysis
No full textInternational audienceIn this review, available knowledge on angular leaf spot (ALS) of bean, caused by Phaeoisariopsis griseola, is analysed and synthesised. This is done through a systems-analytical approach, and successive flowcharts of the system, in order to identify knowledge gaps and guide further research. Six connected sub-models of the ALS monocycle are used as a framework: lesion establishment, lesion extension, defoliation, sporulation, spore liberation, and spore deposition. Each of the sub-models enables the linking of processes to various effects of environmental (physical and host) factors. Disease-induced defoliation is one feature of the pathosystem, leading to a depletion of infectious tissues from the canopy, which are transferred to the ground. Consequences of defoliation may include: strong reductions of the amount of inoculum and of vacant sites in the canopy, limited maximum disease severity, and progressive accumulation of inoculum below the canopy, which may become impor! tant a later stage of disease epidemics. These elements are hypothesised to explain the typical behaviour of ALS epidemics in the field, especially late onset, high apparent rate of disease increase, and low level of terminal disease severity in the standing canopy. Epidemiological consequences of lesion expansion, sporulation, and survival of spores deposited onto the canopy are other knowledge gaps in this pathosyste
Sécurisation des pratiques en réanimation : mise au point d’un outil de validation des incompatibilités entre les médicaments injectables administrés en Y
Full text linkEffect of simulated rainfall events on spore dispersal and spore stocks in three tropical pathosystems
Full text linkTap 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
Effect of simulated rainfall events on spore dispersal and spore stocks in three tropical pathosystems
Full text linkTap 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
Isolation of photoprotective signal transduction mutants by systematic bioluminescence screening in Chlamydomonas reinhardtii
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