scholarly journals Phenology of Infection on Apple Fruit by Sooty Blotch and Flyspeck Species in Iowa Apple Orchards

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 352-359 ◽  
Author(s):  
S. I. Ismail ◽  
J. C. Batzer ◽  
T. C. Harrington ◽  
M. L. Gleason
Keyword(s):  
Fruit Set ◽  
Cost Effective ◽  
Exposure Period ◽  
Apple Fruit ◽  
Economic Losses ◽  
Apple Orchards ◽  
Sooty Blotch ◽  
Sooty Blotch And Flyspeck ◽  
Time Required ◽  
Fruit Surface

Sooty blotch and flyspeck (SBFS) is a fungal disease complex that can cause significant economic losses to apple growers by blemishing the fruit surface with dark-colored colonies. Little is known about the phenology of host infection for this diverse group of epiphytes. In 2009 and 2010, we investigated the timing of infection of apple fruit by SBFS species in six commercial apple orchards in Iowa. Five trees in each orchard received no fungicide sprays after fruit set. Within 3 weeks after fruit set, 60 apples per tree were covered with Japanese fruit bags to minimize inoculum deposition. Subsequently, a subsample of bagged apples was exposed for a single 2-week-long period and then rebagged for the remainder of the growing season. Experimental treatments included seven consecutive 2-week-long exposure periods; control treatments were apples that were either bagged or exposed for the entire season. After apples had been stored at 2°C for 6 weeks following harvest, all SBFS colonies on the apples were identified to species using a PCR-RFLP protocol. A total of 15 species were identified. For the seven most prevalent species, the number of infections per cm2 of fruit surface was greatest on apples that had been exposed early in the season. Two SBFS species, Peltaster fructicola and Colletogloeopsis-like FG2, differed significantly from each other in time required to attain 50% of the total number of colonies per apple, and analysis of variance indicated a significant interaction of SBFS taxon with exposure period. Our findings are the first evidence of species-specific patterns in timing of SBFS inoculum deposition and infection on apple fruit, and strengthen previous observations that most SBFS infections resulting in visible colonies at harvest develop from infections that occur early in the fruit development period. By defining taxon-specific phenological patterns of fruit infection, our findings, when combined with knowledge of region-specific patterns of taxon prevalence, provide a foundation for development of more efficient and cost-effective SBFS management tactics.

scholarly journals First Report of Sooty Blotch and Flyspeck Caused by Species of Dissoconium, Mycosphaerella, and Peltaster on Hawthorn Fruit in China

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 670-670 ◽  
Author(s):  
H. Y. Li ◽  
R. Zhang ◽  
G. Y. Sun ◽  
M. Tang ◽  
M. L. Gleason
Keyword(s):  
Apple Fruit ◽  
Shaanxi Province ◽  
Nuclear Ribosomal Dna ◽  
Economic Losses ◽  
First Report ◽  
Sooty Blotch ◽  
Putative Species ◽  
Sooty Blotch And Flyspeck ◽  
Hawthorn Fruit ◽  
Reservoir Hosts

Sooty blotch and flyspeck (SBFS), a disease complex comprised of as many as 30 putative species of fungi, occurs on the cuticle of pome fruits in moist production regions worldwide, inciting cosmetic damage that causes significant economic losses (1). Chinese hawthorn (Crataegus pinnatifida Bge.) is an economically important tree species in China. Its fruit are sold fresh or dried and are used as a culinary spice as well as an ingredient in Chinese traditional medicine. In October of 2007, Chinese hawthorn fruit exhibiting SBFS signs were sampled from supermarkets in Yangling, Shaanxi Province and Luoyang, Henan Province, China. Thalli directly from the hawthorn fruit were transferred onto potato dextrose agar (PDA) slants under a dissecting microscope and cultured at 22 ± 1°C in darkness. DNA was extracted from pure isolates and the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA (nrDNA) was amplified and sequenced using primers ITS-1F and ITS4 (3). Phylogenetic analysis of the ITS sequences revealed that the 35 isolates generated in this study included five species in three genera: Dissoconium sp. (18 isolates), Mycosphaerella sp. (5 isolates), and Peltaster sp. 1 (4 isolates), Peltaster sp. 2 (4 isolates), and Peltaster sp. 3 (4 isolates). To fulfill Koch's postulates and verify that these fungi could also infest apple fruit, two representative isolates of each putative species were inoculated onto mature intact hawthorn and apple (cv. Fuji) fruit that had been surface disinfested with 75% ethanol and allowed to dry. Inoculum was prepared by comminuting 1-month-old cultures growing on PDA into a suspension of mycelial fragments and conidia (105 to ~106 CFU/ml) in a blender with sterile deionized water (SDW). Each isolate was inoculated on three hawthorn and three apple fruit by using cotton swabs. As controls, two surface-disinfested hawthorn and apple fruit were swabbed with SDW. After the inoculated hawthorn and apple fruit had been incubated in a moist chamber at 22 ± 1°C for 1 month, all inoculated hawthorn and apple fruit exhibited SBFS signs similar to those of the original colonies on hawthorn fruit, but the controls did not. Reservoir hosts have been inferred to play an important role in SBFS by providing the fungi with overwintering habitat and inoculum for infestations on apple. Many reservoir hosts have been reported in the United States and Japan (2). To our knowledge, this is the first report of fungi in the SBFS complex on hawthorn fruit and the first confirmation that fungi growing on hawthorn fruit can produce SBFS signs on apple fruit. These results identify hawthorn as a potential inoculum source for SBFS in apple orchards. References: (1) J. C. Batzer et al. Mycologia 97:1283, 2005. (2) K. Hemnani et al. Phytopathology 98(suppl):S66, 2008. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of Five Sooty Blotch and Flyspeck Fungi on Prunus americana in the United States

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1685-1685 ◽  
Author(s):  
J. Latinović ◽  
J. C. Batzer ◽  
K. B. Duttweiler ◽  
M. L. Gleason ◽  
G. Sun
Keyword(s):  
United States ◽  
The United States ◽  
Apple Fruit ◽  
Economic Losses ◽  
Research Station ◽  
First Report ◽  
Sooty Blotch ◽  
Sooty Blotch And Flyspeck ◽  
Pcr Products ◽  
Pure Cultures

The sooty blotch and flyspeck (SBFS) complex includes more than 30 fungi that blemish the cuticle of apple fruit, causing economic losses in humid regions worldwide (1). In August 2005, we sampled SBFS-infested wild plum (Prunus americana) fruit growing in hedgerows in Iowa. Colonies were categorized according to mycelial type (1), and isolates were made from representative colonies onto acidified water agar (AWA). Plum skins with SBFS signs were excised, pressed, and photographed. DNA was obtained from purified isolates and also from mycelium and fruiting bodies scraped directly from plum fruit skins. Extracted DNA was amplified using primer pair ITS1-F/Myc1-R (ACTCGTCGAAGGAGCTACG) and PCR products were sequenced using primer pair ITS-1F/ITS4. Six sequences were obtained from pure cultures and seven from colonies on plum fruit skin. BLAST analysis of the 470-bp sequences showed 100% homology to five known species in the SBFS complex: Zygophiala cryptogama, Zygophiala wisconsinensis, Pseudocercosporella sp. RH1, and Stomiopeltis spp. RS1 and RS2 (GenBank Accession Nos. AY598854, AY598853, AY5988645, AY598882, and AY598883, respectively). Observations of colony and fruiting structure morphology from cultures on potato dextrose agar (PDA) and colonies on plums confirmed species identity. A modified version of Koch's postulates was conducted to verify that these fungi caused the signs observed on plum and could also infest apple fruit. In June 2006, 1-month-old cultures on PDA were pulverized in a blender with sterile distilled water, passed through four layers of sterile cheesecloth, and transferred to sterile jars. Each isolate was inoculated onto 20 fruit on plum trees (P. americana) on the Iowa State University (ISU) campus and 20 fruit on cv. Golden Delicious apple trees at the ISU Research Station, Gilbert, IA. Each fruit was disinfested with 70% ethanol, air dried, swabbed with inoculum, and covered with a Fuji bag. At harvest, fungal colonies on fruit were reisolated onto AWA. DNA was extracted from pure cultures; when isolations on agar were unsuccessful, DNA was extracted directly from colonies on fruit. PCR was conducted using ITS1-F/Myc1-R, and PCR products were sequenced using ITS1-F/ITS4. All five species were reisolated and sequenced from apple. Pseudocercosporella sp. RH1 and Stomiopeltis sp. RS1 were sequenced from inoculated plums. Although flyspeck, presumably caused by Schizothyrium pomi, was reported on Japanese plum (P. salicina) in Japan (2) and black cherry (P. serotina) in the United States (3), to our knowledge this is the first report of SBFS fungi on plum in the United States and the first confirmation that fungi from plum can produce SBFS signs on apple fruit. Wild plum may therefore act as a reservoir host, providing inoculum for SBFS infestations on apple. References: (1) J. Batzer et al. Mycologia 97:1268, 2005. (2) H. Nasu and H. Kunoh. Plant Dis. 71:361, 1987. (3) T. B. Sutton. Plant Dis. 72:801, 1988.

scholarly journals First Report of Microcyclosporella mali Causing Sooty Blotch and Flyspeck Disease on Plum in Poland

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 493-493
Author(s):  
E. Mirzwa-Mróz ◽  
M. Wińska-Krysiak ◽  
J. Marcinkowska ◽  
M. L. Gleason
Keyword(s):  
Tap Water ◽  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Apple Fruit ◽  
Economic Losses ◽  
First Report ◽  
Sooty Blotch ◽  
Sooty Blotch And Flyspeck ◽  
Branched Chains

Sooty blotch and flyspeck (SBFS), a disease caused by a complex of fungi, results in substantial economic losses for commercial growers of scab-resistant apple (Malus × domestica Borkh.) cultivars in Poland. However, many species causing SBFS in Poland are unidentified and sources of inoculum are uncertain. In August 2009, signs of SBFS were noted on fruit of plum (Prunus domestica L., cvs. Sweet Common Prune and Oullins Golden Gage) in orchards near Mostki in central Poland. Colonies consisted of olive green-to-black mycelial mats with few sclerotium-like bodies; infections ranged in severity from scattered spots to nearly complete coverage of the fruit surface. Ten of these colonies were isolated on potato dextrose agar (PDA). After 10 days of incubation at 22°C, total DNA was extracted; amplification of the internal transcribed spacer (ITS) region of rDNA utilized primers ITS1 and ITS4 (1). Nucleotide sequences were analyzed by ClustalW and compared with sequences in GenBank using BLAST. Sequences showed 99 to 100% homology to Microcyclosporella mali (2), which was formerly assigned as Pseudocercosporella sp. (1). Sequences from five isolates were submitted to GenBank (Accession Nos. HM101275, HM101276, HM101277, HM101278, and HM101279). Morphological characteristics–conidiogenous cells integrated, sympodial and polyblastic; conidial scars nonthickened and inconspicuous; conidia hyaline, subcylindric, narrow, straight or very slightly curved, truncate at the base and obtuse at the apex, often catenulate in simple or branched chains, with one (commonly) to five septa (12.5 × 2.6 to 50.7 × 4.0 μm)–were consistent with descriptions of M. mali (2). To fulfill Koch's postulates, each of the 10 isolates was used to inoculate three healthy apple fruit (cv. Golden Delicious) that had been previously washed under tap water and disinfested with 70% ethanol. After fruit were swabbed with cotton plugs that had been saturated with a suspension of spores in sterile distilled water (SDW), inoculated fruit were placed on filter paper that had been moistened with SDW, then sealed in foil bags and incubated at 22°C. When bags were removed 5 weeks later, dark colonies had appeared on the fruit. Isolates obtained from these colonies were morphologically identical to those used for inoculation. Control (SDW-inoculated and noninoculated) fruit that were incubated in the same manner developed no colonies. To our knowledge, this is the first report of SBFS on plum caused by M. mali in Poland; it had previously been noted as part of the SBFS complex on apple in Germany and Slovenia (2) and on apple and plum in the United States (3). References: (1) J. C. Batzer et al. Mycologia 97:1268, 2005. (2) J. Frank et al. Persoonia 24:93, 2010. (3) J. Latinović et al. Plant Dis. 91:1685, 2007.

Improving sooty blotch and flyspeck severity estimation on apple fruit with the aid of standard area diagrams

2010 ◽  
Vol 129 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Piérri Spolti ◽  
Luana Schneider ◽  
Rosa M. V. Sanhueza ◽  
Jean C. Batzer ◽  
Mark L. Gleason ◽  
...  
Keyword(s):  
Apple Fruit ◽  
Severity Estimation ◽  
Sooty Blotch ◽  
Sooty Blotch And Flyspeck

scholarly journals Evaluating the Performance of a Relative Humidity-Based Warning System for Sooty Blotch and Flyspeck in Iowa

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1721-1728 ◽  
Author(s):  
Hafizi Rosli ◽  
Derrick A. Mayfield ◽  
Jean C. Batzer ◽  
Philip M. Dixon ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Warning System ◽  
Decision Support Tool ◽  
Cost Effective ◽  
Economic Benefits ◽  
Tree Canopy ◽  
Support Tool ◽  
Sooty Blotch ◽  
Budget Analysis ◽  
Sooty Blotch And Flyspeck

A warning system for the sooty blotch and flyspeck (SBFS) fungal disease complex of apple, developed originally for use in the southeastern United States, was modified to provide more reliable assessment of SBFS risk in Iowa. Modeling results based on previous research in Iowa and Wisconsin had suggested replacing leaf wetness duration with cumulative hours of relative humidity (RH) ≥97% as the weather input to the SBFS warning system. The purpose of the present study was to evaluate the performance of a RH-based SBFS warning system, and to assess the potential economic benefits for its use in Iowa. The warning system was evaluated in two separate sets of trials—trial 1 during 2010 and 2011, and trial 2 during 2013–2015—using action thresholds based on cumulative hours of RH ≥97% and ≥90%, respectively, in conjunction with two different fungicide regimes. The warning system was compared with a traditional calendar-based system that specified spraying at predetermined intervals of 10 to 14 days. In trial 1, use of the RH ≥97% threshold caused substantial differences between two RH sensors in recording number of hours exceeding the threshold. When both RH thresholds were compared for 2013–2015, on average, RH ≥90% resulted in a 53% reduction in variation of cumulative hours between two identical RH sensors placed adjacent to each other in an apple tree canopy. Although both the SBFS warning system and the calendar-based system resulted in equivalent control of SBFS, the warning system required fewer fungicide sprays than the calendar-based system, with an average of 3.8 sprays per season (min = 2; max = 5) vs. 6.4 sprays per season (min = 5; max = 8), respectively. The two fungicide regimes provided equivalent SBFS control when used in conjunction with the warning system. A partial budget analysis showed that using the SBFS warning system with a threshold of RH ≥90% was cost effective for orchard sizes of >1 ha. The revised warning system has potential to become a valuable decision support tool for Midwest apple growers because it reduces fungicide costs while protecting apples as effectively as a calendar-based spray schedule. The next step toward implementation of the SBFS warning system in the North Central U.S. should be multiyear field testing in commercial orchards throughout the region.

scholarly journals Diversity and Biogeography of Sooty Blotch and Flyspeck Fungi on Apple in the Eastern and Midwestern United States

2010 ◽  
Vol 100 (4) ◽  
pp. 345-355 ◽  
Author(s):  
María M. Díaz Arias ◽  
Jean C. Batzer ◽  
Thomas C. Harrington ◽  
Amy Wang Wong ◽  
Steven C. Bost ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
Large Subunit ◽  
Morphological Characteristics ◽  
Taxonomic Diversity ◽  
Apple Fruit ◽  
Geographic Region ◽  
Environmental Biology ◽  
Sooty Blotch ◽  
Efficient Management ◽  
Sooty Blotch And Flyspeck

Sooty blotch and flyspeck (SBFS) fungi on apple fruit were sampled from nine orchards in four midwestern U.S. states during 2000 and 30 orchards in 10 eastern U.S. states during 2005 in order to estimate taxonomic diversity and discern patterns of geographic distribution. Forty apple fruit per orchard were arbitrarily sampled and colonies of each mycelial phenotype were counted on each apple. Representative colonies were isolated, cultures were purified, and DNA was extracted. For representative isolates, the internal transcribed spacer (ITS) and large subunit (LSU) regions of ribosomal DNA were amplified and sequenced. In total, 60 SBFS putative species were identified based on ITS sequences and morphological characteristics; 30 of these were discovered in the 2005 survey. Modified Koch's postulates were fulfilled for all 60 species in an Iowa orchard; colonies resulting from inoculation of apple fruit were matched to the original isolates on the basis of mycelial type and ITS sequence. Parsimony analysis for LSU sequences from both surveys revealed that 58 putative SBFS species were members of the Dothideomycetes, 52 were members of the Capnodiales, and 36 were members of the Mycosphaerellaceae. The number of SBFS species per orchard varied from 2 to 15. Number of SBFS species and values of the Margalef and Shannon indexes were significantly (P < 0.05) lower in 21 orchards that had received conventional fungicide sprays during the fruit maturation period than in 14 unsprayed orchards. Several SBFS species, including Schizothyrium pomi, Peltaster fructicola, and Pseudocercosporella sp. RH1, were nearly ubiquitous, whereas other species, such as Stomiopeltis sp. RS5.2, Phialophora sessilis, and Geastrumia polystigmatis, were found only within restricted geographic regions. The results document that the SBFS complex is far more taxonomically diverse than previously recognized and provide strong evidence that SBFS species differ in geographic distribution. To achieve more efficient management of SBFS, it may be necessary to understand the environmental biology of key SBFS species in each geographic region.

Sensitivity of Newly Identified Clades in the Sooty Blotch and Flyspeck Complex on Apple to Thiophanate-methyl and Ziram

2003 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Tara Tarnowski ◽  
Jean Batzer ◽  
Mark Gleason ◽  
Sara Helland ◽  
Phillip Dixon
Keyword(s):  
Radial Growth ◽  
Large Subunit ◽  
Apple Orchards ◽  
Parsimony Analysis ◽  
Fungicide Sensitivity ◽  
Thiophanate Methyl ◽  
Disease Complex ◽  
Sooty Blotch ◽  
Sooty Blotch And Flyspeck ◽  
Practical Implications

Sensitivity to the fungicides thiophanate-methyl and ziram was characterized for newly identified clades in the sooty blotch and flyspeck (SBFS) disease complex. Isolates obtained from apple orchards in Illinois, Iowa, Missouri, and Wisconsin were previously grouped into clades based on parsimony analysis of the internal transcriber spacer (ITS) and large subunit (LSU) regions of rDNA. Two isolates from each of eight clades were cultured on water agar amended with a range of fungicide concentrations. Radial growth of colonies was measured after incubation for 21 days at 25°C. Fungicide sensitivity (ED50) did not differ significantly (P = 0.05) between isolates within a clade, but several clades differed significantly. There was a greater variability among clades for sensitivity to thiophanate-methyl than for ziram. Significant differences in fungicide sensitivity among, but not within, clades provide evidence that these clades differ physiologically. Understanding differences in fungicide sensitivity among SBFS clades could have practical implications for improved management of SBFS. Accepted for publication 12 November 2003. Published 9 December 2003.

scholarly journals Precipitation Impacts Dissemination of Three Sooty Blotch and Flyspeck Taxa on Apple Fruit

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2398-2405
Author(s):  
Hafizi Rosli ◽  
Jean C. Batzer ◽  
Edward Hernández ◽  
Gustavo Beruski ◽  
Philip M. Dixon ◽  
...  
Keyword(s):  
Fruit Development ◽  
Apple Fruit ◽  
Apple Orchard ◽  
Colony Development ◽  
Sooty Blotch ◽  
Splash Dispersal ◽  
Overhead Irrigation ◽  
Sooty Blotch And Flyspeck ◽  
Irrigation Levels ◽  
Spore Dissemination

The spatial dissemination of three prevalent taxa of sooty blotch and flyspeck (SBFS) fungi under several levels of precipitation was compared during 2015 and 2016 in an Iowa apple orchard. Overhead irrigation was used to supplement ambient precipitation in order to insure SBFS spore dissemination and colony development. There were five irrigation levels, involving 1-min-long periods of irrigation that were imposed either once or twice per hour at intervals of 3, 6, or 12 h, as well as a nonirrigated control. Preselected apple fruit were inoculated with one of the three SBFS taxa to serve as sources of inoculum. Dissemination from these inoculated apple fruit was assessed at harvest by counting SBFS colonies on water-sprayed and nontreated fruit. As a further control, additional fruit were enclosed in fruit bags throughout the fruit development period. In both 2015 and 2016, the number of colonies of the SBFS fungus Peltaster gemmifer per apple increased sharply as the duration of irrigation increased, whereas the number of colonies of Microcyclosporella mali increased to a lesser extent and Stomiopeltis sp. RS1 showed no increase. In 2015, the linear relationship between the duration of irrigation-imposed precipitation levels and the number of colonies on the water-sprayed apple fruit was similar for P. gemmifer (slope = 0.09), Stomiopeltis sp. RS1 (slope = 0.07), and Microcyclosporella mali (slope = 0.13); whereas, in 2016, the slope was higher for P. gemmifer (0.28) than for Stomiopeltis sp. RS1 (−0.09) or M. mali (0.06). The results indicated that dissemination of P. gemmifer increased sharply in response to increased irrigation-imposed precipitation, and that dissemination patterns differed considerably among the three SBFS taxa. The apparent advantage of P. gemmifer in precipitation-triggered dissemination may stem from its ability to produce spores rapidly by budding. To our knowledge, this is the first article to assess splash dispersal by SBFS fungi in the field and the first to document taxon-specific patterns of dissemination in this pathogen complex.

Sign in / Sign up

Export Citation Format

Share Document