Studies on the Mode of Survival of Diplocarpon mali Causing Premature Leaf Fall of Apple

Goyal, Anupam; Sharma, J.N.; Phurailatpam, Sumitra

doi:10.20546/ijcmas.2018.708.249

Cited by 5 publications

(2 citation statements)

References 3 publications

(5 reference statements)

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“…In addition to the timing of primary infections, we were also interested in the origin of the primary inoculum. Several studies report that conidia inside acervuli overwinter in leaf litter (Back et al 2015;Dong et al 2015;Gao et al 2011;Goyal et al 2018;Lee et al 2011;Sastrahidayat and Nirwanto 2016;Sharma et al 2009). This is in accordance with our finding of Dc spores above leave litter deposits in spring and also with the observation that in May, most spores were captured in the Mycotrap on the ground, and not in the Mycotrap in the tree canopy.…”

Section: Discussionmentioning

confidence: 99%

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Boutry

Bohr²,

Buchleither³

et al. 2023

Phytopathology®

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Apple blotch (AB) is a major disease of apple in Asia and recently emerged in Europe and the USA. It is caused by the fungus Diplocarpon coronariae (Dc) (formerly: Marssonina coronaria; teleomorph: Diplocarpon mali) and leads to severe defoliation of apple trees in late summer resulting in reduced yield and fruit quality. To develop effective disease management strategies, a sound knowledge of the pathogen’s biology is crucial. Data on the early phase of disease development is scarce: no data on spore dispersal in Europe is available. We developed a highly sensitive TaqMan qPCR method to quantify Dc conidia in spore trap samples. We monitored temporal and spatial dispersal of conidia of Dc, and progress of AB in spring and early summer in an extensively managed apple orchard in Switzerland in 2019 and 2020. Our results show that Dc overwinters in leaf litter and spore dispersal and primary infections occur in late April and early May. We provide the first results describing early-season dispersal of conidia of Dc, which, combined with the observed disease progress, helps to understand the disease dynamics and will be a basis for improved disease forecast models. Using the new qPCR method, we detected Dc in buds, on bark, and on fruit mummies, suggesting that several apple tissues may serve as overwintering habitats for the fungus, in addition to fallen leaves.

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Section: Discussionmentioning

confidence: 99%

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Boutry

Bohr²,

Buchleither³

et al. 2023

Phytopathology®

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“…In addition to the timing of the primary infections, we were also interested in the origin of the primary inoculum. Several studies report that conidia inside acervuli are overwintering on fallen infected leaves (Back et al 2015;Dong et al 2015;Gao et al 2011;Goyal et al 2018;Lee et al 2011;Sastrahidayat and Nirwanto 2016;Sharma et al 2009). The conidia are released in a water film on the leaf surface and are then dispersed by rain splashes onto apple leaves (Hinrichs-Berger 2015).…”

Section: Leaf Litter and Other Sources Of Primary Inoculummentioning

confidence: 99%

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Boutry

Bohr

Buchleither

et al. 2021

Preprint

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Apple blotch (AB) is a major disease of apples in Asia and recently also emerging in Europe and the USA. It is caused by the fungus Diplocarpon coronariae (Dc) (formerly: Marssonina coronaria; teleomorph: Diplocarpon mali) and leads to severe defoliation of apple trees in late summer and thus to reduced yield and fruit quality. To develop effective crop protection strategies, a sound knowledge of the pathogen's biology is crucial. However, especially data on the early phase of disease development is scarce, and no data on spore dispersal for Europe is available. In this study, we assessed different spore traps for their capacity to capture Dc spores, and we developed a highly sensitive TaqMan qPCR method to quantify Dc conidia in spore trap samples. With these tools, we monitored the temporal and spatial spore dispersal and disease progress in spring and early summer in an extensively managed apple orchard in Switzerland in 2019 and 2020. Our results show that Dc overwinters in leaf litter and that spore dispersal and primary infections occur already in late April and beginning of May. We provide the first results on early-season spore dispersal of Dc, which, combined with the observed disease progress, helps to understand the disease dynamics and improve disease forecast models. Using the new qPCR method, we finally detected Dc in buds, on bark and on fruit mummies, suggesting that these apple organs may serve as additional overwintering habitats for the fungus.

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Effects of Temperature and Moisture on Conidia Germination, Infection, and Acervulus Formation of the Apple Marssonina Leaf Blotch Pathogen (Diplocarpon mali) in China

Lian

Dong

et al. 2021

Plant Disease

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Apple marssonina leaf blotch (Diplocarpon mali) is a severe disease of apple that mainly causes premature leaf defoliation in many apple growing areas in the word. Its epidemic development is closely related to temperature and rainfall. The effects of temperature and moisture on conidium germination, infection on leaves, and acervulus production were investigated under controlled environments. Temperature required for conidium germination and infection ranged from 5 oC to 30 oC with the optimum around 23 oC, and temperature required for acervulus formation was slightly wider with the optimum at 24.6 oC. Wetness was needed for conidia to germinate and infect; only few conidia germinated at RH=100%. However, lesions can produce acervuli in dry conditions. The minimum duration of leaf wetness required for conidia to complete the entire infection process were 14, 8, 4, and 6 hours at 10, 15, 20, and 25°C, respectively. A model describing the effect of temperature and leaf wetness duration was built. The model estimated that conidial infection has the optimum temperature at 22.6°C and the minimum wetness duration required of 4.8 hours. The model can be used to forecast the conidial infection of D. mali to assist in disease management in commercial apple production.

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Studies on the Mode of Survival of Diplocarpon mali Causing Premature Leaf Fall of Apple

Cited by 5 publications

References 3 publications

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Monitoring Spore Dispersal and Early Infections of Diplocarpon coronariae Causing Apple Blotch Using Spore Traps and a New qPCR Method

Effects of Temperature and Moisture on Conidia Germination, Infection, and Acervulus Formation of the Apple Marssonina Leaf Blotch Pathogen (Diplocarpon mali) in China

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