scholarly journals Fungal communities isolated from dead apple leaves from orchards in Quebec

2005 ◽  
Vol 77 (3) ◽  
pp. 129-134 ◽  
Author(s):  
J. Bernier ◽  
O. Carisse ◽  
T.C. Paulitz
Keyword(s):  
North America ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Causal Agent ◽  
Biocontrol Agents ◽  
Fungal Communities ◽  
Malus Pumila ◽  
Apple Leaves

Venturia inaequalis, the causal agent of apple scab, overwinters in apple (Malus pumila) leaves on the orchard floor by producing pseudothecia. The objectives of this survey were to make a collection of fungi to be subsequently tested for their potential as psychrophile biocontrol agents against V. inaequalis and to acquire knowledge on the diversity of the microflora of dead apple leaves. Fungi were recovered from dead apple leaves collected in the spring and fall of 1993. A total of 345 isolates from 49 genera were identified. Fifteen gene were not previously recorded as colonizers of apple leaves in North America.

Constituents from Morus root bark against Venturia inaequalis – the causal agent of apple scab

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
JM Rollinger ◽  
R Spitaler ◽  
M Menz ◽  
P Schneider ◽  
EP Ellmerer ◽  
...  
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Causal Agent ◽  
Root Bark

scholarly journals A genetic linkage map of Venturia inaequalis, the causal agent of apple scab

2009 ◽  
Vol 2 (1) ◽  
pp. 163 ◽  
Author(s):  
Xiangming Xu ◽  
Tony Roberts ◽  
Dez Barbara ◽  
Nick G Harvey ◽  
Liqiang Gao ◽  
...  
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Causal Agent

scholarly journals A New Phytosanitary Method to Reduce the Ascospore Potential of Venturia inaequalis

Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 414-420 ◽  
Author(s):  
Franziska M. Porsche ◽  
Barbara Pfeiffer ◽  
Andreas Kollar
Keyword(s):  
Leaf Litter ◽  
Yeast Extract ◽  
Untreated Control ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Nutrient Media ◽  
Apple Leaves ◽  
Litter Decay ◽  
Ascospore Discharge ◽  
Infection Pressure

Ascospores of Venturia inaequalis, released from pseudothecia in overwintered, infected apple leaves, serve as the primary inoculum for apple scab. In this study, we tested a new sanitation strategy to reduce ascospore inoculum under orchard conditions over three overwintering periods. After leaf fall, nutrient media containing different concentrations of degraded casein or a yeast extract from Saccharomyces cerivisiae were applied to leaf litter infected with apple scab. The application of 30 and 60% yeast extract showed the greatest efficacy, and significantly reduced ascospore discharge by 99% (P < 0.01) in 2013 and 2014. The efficacy of the treatments did not differ from treatment with 5% urea (P > 0.05). Leaf litter decay was accelerated in the plots treated with yeast extract compared with untreated control plots. Moreover, apple leaves treated with yeast extract had completely decayed due to earthworm activity before ascospore maturity. In comparison, up to 26% of the leaves in untreated control plots had not decayed. These results suggest that the treatment of leaf litter with yeast extract can almost completely eliminate apple scab inoculum in the course of the whole primary season. These sanitation practices may be beneficial for both organic and conventional cultivation. The reduced infection pressure may allow growers the usage of fungicides with lower efficacy or to reduce the number of applications needed to manage apple scab in spring.

scholarly journals A 33-year Evaluation of Resistance and Pathogenicity in the Apple Scab–crabapples Pathosystem

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 599-608 ◽  
Author(s):  
Janna Beckerman ◽  
James Chatfield ◽  
Erik Draper
Keyword(s):  
North America ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Apple Breeding ◽  
Residential Landscape ◽  
Ornamental Trees ◽  
First Time ◽  
Trial Plot

Crabapples (Malus spp.) are popular ornamental trees in the commercial and residential landscape. Over a 33-year period at the Secrest Arboretum, Wooster, OH, 287 accessions of ornamental crabapple were evaluated for their resistance to apple scab caused by the fungus Venturia inaequalis. Of these 287 accessions, 31 had no symptoms of scab for longer than a 10-year period and were identified as resistant to the disease. Of these 31 resistant accessions, 14 eventually displayed symptoms, presumably as a result of infection by one or more newly present races of the pathogen in the trial plot. Notable resistance breakdowns in accessions previously classified as resistant include the development of scab on M. × ‘Prairifire’, M. × ‘Bob White’, M. × ‘Red Jewel’, and M. floribunda. Corresponding to these changes of resistance is the putative development of new V. inaequalis races in North America: Race 5, possessing virulence to the Vm gene in ‘Prairifire’; Race 3 that infects M. × ‘Geneva’ but not M. baccata ‘Dolgo’; and the first identification and report of scab on a M. floribunda population that was reported as resistant even before the first 25 years of the evaluation. The detection of scab on this species suggests the presence of Race 7 in North America for the first time. Five named accessions remained free from scab for the entire 33-year trial: M. sargentii ‘Sargent’, M. baccata ‘Jackii’, M. × ‘Beverly’, M. × ‘Silver Moon’, and M. × ‘White Angel’ and may serve as sources of durable resistance in crabapple and commercial apple breeding in the Midwest.

Benomyl-marked populations of Chaetomium globosum: survival on apple leaves with and without benomyl and antagonism to the apple scab pathogen, Venturia inaequalis

1985 ◽  
Vol 31 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Daniel Cullen ◽  
John H. Andrews
Keyword(s):  
Resistant Strain ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Chaetomium Globosum ◽  
Wild Type ◽  
Population Densities ◽  
Apple Trees ◽  
Initial Inoculum ◽  
Apple Leaves ◽  
Rate Of Decline

Resistance to the fungicide benomyl (BenR) was induced with N-methyl-N′-nitro-N-nitrosoguanidine in Chaetomium globosum isolated from apple leaves. The population densities of a resistant strain reintroduced to leaves on apple trees in an orchard were determined at 3 h, and 1 and 3 weeks following inoculation. Relative to wild-type parents, BenR populations declined more rapidly on orchard trees, but the rate of decline was reduced by amending initial inoculum with 18.5 ppm benomyl. Survival of BenRC. globosum increased 40–58% relative to BenRC. globosum applied without benomyl. In growth chamber experiments with potted apple seedlings, the BenR strain was as antagonistic as were the wild-type parents to the scab pathogen, Venturia inaequalis. The marked strain alone did not significantly reduce scab infection on saplings in the field; however, when it was applied with benomyl, scab severity was significantly (P = 0.01) less than with benomyl alone.

Sign in / Sign up

Export Citation Format

Share Document