EPIDEMIOLOGY AND MANAGEMENT OF APPLE AND PEACH DISEASES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0222065
• Project Start Date: Apr 1, 2010
• Project End Date: Sep 30, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
WEST VIRGINIA UNIVERSITY
886 CHESTNUT RIDGE RD RM 202
MORGANTOWN,WV 26505-2742

Performing Department
Plant & Soil Sciences

Non Technical Summary
The overall aim of this project is to address selected aspects related to epidemiology and management of pressing disease research needs on apple (Malus x domestica) and peach (Prunus persica), West Virginia's most important fruit crops. In 2008, the two crops were produced on ca. 5,000 and 1,000 acres, and their statewide farm gate values totaled $8.5 and $3.4 million, respectively (NASS, 2008). On the national scale that same year, West Virginia ranked tenth in apple production and eighth in peach production (NASS, 2008). Given the increased consumer awareness of the health benefits of fresh fruits and vegetables along with the increased support for specialty crops in the 2008 Farm Bill, grower interest in the production of fruits will continue to increase in the foreseeable future. Apple and peach production in West Virginia are favored by early harvest dates, relative to other northeast locations, which enable premium producer prices. Unfortunately, however, the state's warm and often humid climate is associated with substantial disease problems in both crops. In apple, fungal diseases, particularly apple scab, powdery mildew, rust diseases and fire blight are very widespread, but - owing in part to WVU research and extension efforts during the past 20 years - these diseases are generally well controlled. This is perhaps best illustrated by the low (s Cooperative Extension Service. Undoubtedly these enormous losses were favored by disease-conducive weather in these two years, but two troubling trends contributed significantly to disease control failure and increased losses: fungicide resistance in M. fructicola. Thus, the third and fourth objectives of this project are concerned with, respectively, fungicide resistance management of M. fructicola, and efforts to improve management of brown rot disease in mid-Atlantic region peach orchards.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1110	1160	50%
212	1114	1160	50%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1114 - Peach; 1110 - Apple;

Field Of Science
1160 - Pathology;

Keywords

west virginia

apple scab

fire blight

brown rot

maryblyt

disease forecasting

disease management

fungicide resistance

Goals / Objectives
The objectives of this project include: 1) Validate fire blight forecasting software Maryblyt for Windows version 7; 2)Provide data on the population structure of Venturia inaequalis with respect to its sensitivity to key fungicide classes; 3)Develop data on the population structure of Monilinia fructicola with respect to its sensitivity to key fungicide classes; 4)Based on data collected in Objective 2 and 3, develop a regional resistance management strategy for pome and stone fruits in the eastern U.S.; and 5)Develop and test a brown rot infection risk model to develop strategies for improved brown rot forecasting and fungicide resistance management. Outputs will include validated fire blight forecasting software, data and publications on fungicide resistance for the apple scab and brown rot pathogens, publications on resistance management for tree fruit diseases, a prototype brown rot risk model.

Project Methods
To assure rapid implementation of the results, historic data will be used to initiate the study. The data will consist of a subset of the original Maryblyt data sets and data collected over several years from WV orchards, as well as data from other fruit pathologists. Additional data will be collected over a three-year period as described below. Orchards in which Maryblyt will be evaluated are located at the AFRS in Bardane, WV, the TFREC Kearneysville, and the WMREC in Keedysville (27 km northeast of AFRS). At AFRS, all weather and research data will be collected in blocks of susceptible apple. To determine the presence of epiphytic bacteria, bulk samples of blossoms will be collected once or twice each week from a 1.5- to 4.0-ha orchard block. A 0.1-ml sample of wash water from each bag will be spread on M-S medium. Plates will be incubated at 26 C for 48-72 hr, and E. amylovora colonies counted. The model's EIP index will be compared with the recovery of E. amylovora from blossoms and the first blossom blight symptom prediction of the season will be compared with the appearance of natural symptoms. A nonparametric sign test will be used to test the null hypothesis that each difference between observed and predicted fire blight had a median value of 0. At KTFREC and WMREC, the Maryblyt model will be evaluated in blocks of Rome Beauty apples. Temperature and rainfall data will be collected. The number of fire blight strikes per tree will be counted approximately 1 week after Maryblyt predicts BBS. Presence of E. amylovora in blossoms will be confirmed by isolation on NYGA. Symptom development will be monitored and compared with Maryblyt. Copies of the Maryblyt program will be distributed to growers. For brown rot modeling, field trials will be conducted in orchards at KTFREC in 2010 - 2014. During bloom, all sites will be surveyed for the presence of mummified fruit and apothecia in the tress and on the ground. Samples of dried and mummified fruit will be collected and incubated to detect M. fructicola. The fruit will be picked into trays inside cardboard cartons which will be enclosed in bags, and incubated. Fruit will be inspected for rots and the causal organisms identified by microscopy. The relationship between postharvest rots and occurrence of brown rot infection periods will be examined in relation to the timing and type of fungicide sprays used. Thirty-five isolates will be collected from mummified fruit and mature fruit. These will be grown on PDA and colony morphology compared against similar age cultures of reference isolates of M. fructicola. Brown rot infection risk model: The Tate Peach Brown rot model will be used to determine the infection risk associated with surface wetness events and temperature. Infection risk for blossom and fruit will be calculated by multiplying the hours of wetness (rain) by the mean temperature during the wet period. The intensity of the infection risk will be categorized as: marginal; light; moderate; or severe. Infection periods predicted by Tate's Peach Brown rot model will be compared to brown rot studies of temperature and wetting and the model adjusted, if needed.

Progress 04/01/10 to 09/30/14

Outputs
Target Audience: Target audience included commercial pome fruit producers and county extension educators. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Producers will be instructed on the use of the updated Maryblyt model. How have the results been disseminated to communities of interest? Results have been dissemination via presentations at producer educational events and in popular articles in trade magazines. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Apple white rot inflicts severe economic losses in the main apple-producing areas in Asia nd North America. In Asia, the causal agent of the disease has been identified by various researchers as Physalospora piricola and Botryosphaeria berengeriana f. sp. piricola, although B. dothidea is currently the more widely accepted pathogen name, especially in North America. In the present study, genealogical concordance phylogenetic species recognition (GCPSR) was applied to pathogenic fungal isolates from apple and pear ring rot from several locations in the US and China. Phylogenetic results based on sequences of four nuclear loci (ITS, EF-1α, HIS and HSP) revealed the existence of an unrecognized, cryptic species within the B. dothidea complex. Morphologically, the cryptic species presented an appressed mycelial mat in Petri dishes (PDA) whereas B. dothidea displayed columns of aerial mycelia reaching the lids, and conidia of the latter were longer than the former. B. dothidea had a faster growth rate than the cryptic species under relatively high temperatures. Pathogenicity tests showed that on pear stems the cryptic species caused large-scale cankers along with blisters whereas B. dothidea was non-pathogenic, but on apple shoots the two fungi induced large and small wart-like prominences, respectively. Overall, this cryptic species demonstrated sufficient genetic variations and biological differences from B. dothidea, and is therefore described here as a new combination, Botryosphaeria kuwatsukai. The epitype is designated. Both B. kuwatsukai and B. dothidea are considered to be the main causal agents for apple white rot. Maryblyt 7.1 was released in 2014. Version 7.1 incorporates several cosmetic and functional changes; the re-programming for Version 7.1 was done by Turechek and Biggs under a subcontract to Walter Britton. Among the changes, Version 7.1 is capable of using international units for decimal numbers (e.g., 20,3) and date formats (DD/MM/YYYY) and this is initiated by selecting the ‘International’ option through the Season Properties dialogue box (Figure 1). Earlier versions were able to accept only U.S. units for numbers and dates, and the program would invariably “crash” if the wrong number and/or date formats were used. The audible warning beep, which was missing in Version 7.0, was re-established to alert users of an infection event. The additional option allowing users to toggle the beep on and off was also incorporated into Version 7.1. The Maryblyt manual was also revised, reformatted, and integrated into the program software. Another option that has been added to Maryblyt 7.1 is the ability to turn on and off the effect that applying antibiotic has on EIP and subsequent blossom blight symptoms (BBS). This is particularly useful so that users can track symptom development as if they had not treated with antibiotics so that BBS can be monitored more effectively and application effectiveness can be evaluated. In a typical scenario, once a spray has been applied, the infection event (denoted as “I” under the BHWTR) will usually be downgraded to a high risk event (“H”) because the EIP is often reduced to below 198 due to the antibiotic application. As a result, the BBS clock will not be activated. However, because applications are less than perfect, it is likely that some infection may have occurred and it is of interest to initiate the BBS clock to track infection. To accomplish this, users can turn off the Spray Mode, temporarily removing the application to allow users to identify when blossom blight symptoms would be expected as if an application was not made. A new feature in Maryblyt 7.1 is the Spray Effectiveness Module which allows users to enter an applicationefficacy threshold to account for treatments that are less than 100% effective. This can be accessed under the Program Thresholds dialogue box. In earlier versions of Maryblyt it was assumed that when an antibiotic was applied, coverage was thorough, that all flowers open at the time of treatment were protected, and that the chemical treatment (agricultural streptomycin) was 100% effective. However, in practice these assumptions often are not met. Users can now account for less than perfect applications (i.e., we often advise growers that streptomycin applied the day after infection is only 90% as effective as streptomycin applied the day before or day of infection), or for applications of alternatives to streptomycin that are known to be less effective, by entering an estimate of the actual level of efficacy into the Spray Effectiveness box. When this is done, the accumulated number of degree-hours is reduced by a factor equal to (100 - % Spray Effectiveness) and subsequent EIP calculations are reset to begin from the date of application; i.e., the 65 degree hour clock starts on the date of application. Users should be aware that this feature is conceptual and has not been tested or validated.

Publications

• Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Xu, C., Wang, C., Ju, L., Zhang, R., Biggs, A. R., Tanaka, E., Sun, G. Y. 2015. Multiple locus genealogies and phenotypic characters reappraise the causal agent of apple ring rot in China. Fungal Diversity 69:xxx-xxx.
• Type: Journal Articles Status: Accepted Year Published: 2015 Citation: Turechek, W. W. and Biggs, A. R. 2015. Maryblyt v. 7.1 for Windows: An Improved Fire Blight Forecasting Program for Apples and Pears. Online. Plant Health Progress doi:xx.xxxx/PHP-2015-xxxx-xx-RS

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Target audience included commercial pome fruit producers and county extension educators. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Results have been dissemination via presentations at producer educational events and in popular articles in trade magazines. What do you plan to do during the next reporting period to accomplish the goals? The project will continue as described. We expect to release an updated version of Maryblyt software in 2014.

Impacts
What was accomplished under these goals? The computer software Maryblyt is utilized extensively for fire blight management. The software was downloaded 290 times in 2013 with visits recorded from 40 countries. The software allows for proper timing of antibiotic applications and facilitates monitoring activities. Project evalutations indicated that users regarded the new software very highly. Apple cultivar evaluations for disease relative susceptibility are widely used by growers to fine tune management strategies for cultivars with notable resistance or susceptibility characteristics. Apple core rot often is a limiting factor in both conventional IPM systems and organic systems, especially with open calyx cultivars such as Fuji. An improved understanding of the fungal complex involved in this disease is needed to reduce fungicide use and production costs. Increasing the postharvest shelf life of papaya with preharvest application of calcium salts is a potential organic alternative to fungicides. We were able to increase the storage life of calcium-treated fruits by up to 4 weeks with preharvest calcium treatments.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Gao, L. L., Zhang, Q., Sun, X. Y., Zhang, R., Sun, G. Y., and Biggs, A. R. 2013. Diversity of pathogens associated with moldy core and core rot of Fuji apple in Shaanxi Province, China. Plant Disease 97:510-516.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Madani, B., Mohamed, M. T. M., Biggs, A. R., Kadir, J., Awang, Y., and Tayebi-Meigooni, A. 2014. Effect of preharvest calcium chloride applications on fruit calcium level and postharvest anthracnose disease of papaya. Crop Protection 55:55-60.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Working with a computer programmer, we initiated the first upgrade to the fire blight prediction model Maryblyt to supplement its recent release in the first Windows-compatible version. Contacts were made to initiate development of wide-scale disease forecasting with a GIS-based system of models and weather data acquisition. After the recent release of Maryblyt v. 7 for Windows, which is available for free from the WVU-KTFREC web site, the software was downloaded by 270 unique users in 2012. We described new biological findings on the apple core rot fungal complex in cooperation with colleagues in China. Results from our previous work with cultivar relative susceptibility testing tests has been made available on a new eXtension web site for apple rootstocks and cultivars, as well on the WVU-KTFREC web site. PARTICIPANTS: The following individuals and institutions were informal cooperators on this project. George W. Sundin, Dept. Plant Pathology, 103 CIPS, Michigan State University, East Lansing 48824; David A. Rosenberger, Cornell University's Hudson Valley Laboratory, Highland, NY 12528; Keith S. Yoder, Dept. of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University Agricultural Research and Extension Center, Winchester 22602; Turner B. Sutton, Dept. Plant Pathology, North Carolina State University, Raleigh 27695; Daniel. R. Cooley, Dept. Plant, Soil, and Insect Science, University of Massachusetts, Amherst 01003; and W. W. Turechek, U.S. Department of Agriculture, Agricultural Research Service, Ft. Pierce, FL. TARGET AUDIENCES: Target audience included commercial producers of apples and pears worldwide. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The computer software Maryblyt is utilized extensively for fire blight management. The software was downloaded 270 times in 2012 with visits recorded from 40 countries. The software allows for proper timing of antibiotic applications and facilitates monitoring activities. Project evalutations indicated that users regarded the new software very highly. Apple cultivar evaluations for disease relative susceptibility are widely used by growers to fine tune management strategies for cultivars with notable resistance or susceptibility characteristics. Apple care rot often is a limiting factor in both conventional IPM systems and organic systems, especially with open calyx cultivars such as Fuji. An improved understanding of the fungal complex involved in this disease is needed to reduce fungicide use and production costs.

Publications

• Hoover, E., Marini, R., Tepe, E., Autio, W., Biggs, A. R., Clements, J., Crassweller, R., Foster, D., Foster, M. J., Miller, D., Parker, M., Racsko, J., Robinson, T., and Warmund, M. 2012. eApples: A Case Study in using eXtension.org to Increase Access to Research-Based Information. HortTechnology 22:576-579.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: We collected data to validate the fire blight prediction model Maryblyt and its recent release in the first Windows-compatible version. Contacts were made to initiate development of wide-scale disease forecasting with a GIS-based system of models and weather data acquisition. After the recent release of Maryblyt v. 7 for Windows, which is available for free from the WVU-KTFREC web site, the software was downloaded by 180 unique users in 2011. We described new biological findings on sooty blotch/fly speck fungal complex in copperation with colleagues in the US, Europe, and China. Results from our previous work with cultivar relative susceptibility testing tests has been made available on a new eXtension web site for apple rootstocks and cultivars, as well on the WVU-KTFREC web site. Studies were initiated to characterize the resistance in the stone fruit brown rot pathogen, Monilinia fructicola. In spiral dilution tests, the EC50 for fenbuconazole ranged from 0.003 to 0.129 microG/microL, and for the baseline isolates ATCC 16103 and ATCC 46606 it was 0.020 and 0.016 microG/microL, respectively. The identity of the isolates at the species level was confirmed using sequences from the ITS region of the nuclear ribosomal RNA gene. PARTICIPANTS: The following individuals and institutions were informal cooperators on this project. George W. Sundin, Dept. Plant Pathology, 103 CIPS, Michigan State University, East Lansing 48824; David A. Rosenberger, Cornell University's Hudson Valley Laboratory, Highland, NY 12528; Keith S. Yoder, Dept. of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University Agricultural Research and Extension Center, Winchester 22602; Turner B. Sutton, Dept. Plant Pathology, North Carolina State University, Raleigh 27695; Daniel. R. Cooley, Dept. Plant, Soil, and Insect Science, University of Massachusetts, Amherst 01003; and W. W. Turechek, U.S. Department of Agriculture, Agricultural Research Service, Ft. Pierce, FL. TARGET AUDIENCES: Target audience included commercial producers of apples and pears worldwide. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The computer software Maryblyt is utilized extensively for fire blight management. The software was downloaded 180 times in 2011 with visits recorded from 35 countries. The software allows for proper timing of antibiotic applications and facilitates monitoring activities. Project evalutations indicated that users regarded the new software very highly. Apple cultivar evaluations for disease relative susceptibility are widely used by growers to fine tune management strategies for cultivars with noteable resistance or susceptibility characterisitcs. Sooty blotch and fly speck disease often is a limiting factor in both conventional IPM systems and organic systems. An improved understanding of the fungal complex involved in this disease is needed to reduce fungicide use and production costs.

Publications

• Gleason, M., Batzer, J., Harrington, T., Guangyu, S., Zhang, R., Diaz, M. M., Sutton, T., Crous, P., Ivanovic, M., McManus, P., Cooley, D., Yoder, K. S., Oertel, B., and Biggs, A. R. 2011. A new view of the sooty blotch and flyspeck complex. Plant Disease 95: 368-383.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: We described the fire blight prediction model Maryblyt and its recent release in the first Windows-compatible version. A brief discussion of the biological basis for the model was provided, including its integrated use of multiple cumulative heat unit "clocks". Furthermore, we described the recent release of Maryblyt v. 7 for Windows, which is available for free from the WVU-KTFREC web site. We described the relative susceptibility of 45 apple cultivars to apple scab and the sooty blotch/fly speck fungal complex. Data were collected over several years from plantings of new apple cultivars and selections established at multiple locations in 1995 (23 entries) and 1999 (22 entries) as part of regional project NE-183. Golden Delicious and McIntosh were the standards in both plantings. Data on incidence of scab on leaves and fruit were collected and analyzed to determine differences due to location and cultivar. None of the analyses indicated significant cultivar differences due to location, likely confirming the diversity of the apple scab fungus in the eastern United States. In general, for scab on leaves, the cultivars Ginger Gold, Orin, Cripps Pink, Silken, and Delblush were as susceptible as McIntosh, a common standard for scab susceptibility in the eastern United States. For scab on fruit, the cultivars Fuji, Cameo, Cripps Pink, Ambrosia, and Silken, and the selection NJ 90, were as susceptible as McIntosh. As expected, the cultivars and selections with genetic resistance to the scab pathogen exhibited the lowest incidences of apple scab on foliage and fruit. Gala Supreme, Sansa, and Honeycrisp, while susceptible to scab, exhibited relatively low levels of the disease. For sooty blotch and fly speck, cultivar differences were primarily the result of harvest date, with cultivars that were harvested latest having the highest disease incidences. Lower SBFS incidence on the earlier maturing cultivars apparently resulted from disease avoidance, as these apples were exposed to fewer hours of wetting and high relative humidity, environmental factors favorable for growth of SBFS fungi. Management tactics targeting SBFS are especially critical for cultivars that mature late in the season. Results from cultivar tests will be made available on a new eXtension web site for apple rootstocks and cultivars, as well on the WVU-KTFREC web site. PARTICIPANTS: The following individuals and institutions were informal cooperators on this project. George W. Sundin, Dept. Plant Pathology, 103 CIPS, Michigan State University, East Lansing 48824; David A. Rosenberger, Cornell University's Hudson Valley Laboratory, Highland, NY 12528; Keith S. Yoder, Dept. of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University Agricultural Research and Extension Center, Winchester 22602; Turner B. Sutton, Dept. Plant Pathology, North Carolina State University, Raleigh 27695; Daniel. R. Cooley, Dept. Plant, Soil, and Insect Science, University of Massachusetts, Amherst 01003; and W. W. Turechek, U.S. Department of Agriculture, Agricultural Research Service, Ft. Pierce, FL. TARGET AUDIENCES: Target audience included commercial producers of apples and pears worldwide. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The computer software Maryblyt is utilized extensively for fire blight management. The software was downloaded 145 times in 2010 with visits recorded from 25 countries. The software allows for proper timing of antibiotic applications and facilitates monitoring activities. Project evalutations indicated that users regarded the new software very highly. Apple cultivar evaluations for disease relative susceptibility are widely used by growers to fine tune management strategies for cultivars with noteable resistance or susceptibility characterisitcs. A poster summarizing the results of all the disease evaluations was prepared and displayed at five regional growers meetings.

Publications

• Biggs, A. R., and Turechek, W. W. 2010. Fire blight of apples and pears: epidemiological concepts comprising the Maryblyt forecasting program. Online. Plant Health Progress doi:10.1094/PHP-2010-0315-01-RS.
• Biggs, A. R., Sundin, G., Rosenberger, D. A., Yoder, K. S., and Sutton, T. B. 2010. Relative susceptibility of selected apple cultivars and selections to apple scab caused by Venturia inaequalis. Plant Health Progress doi:10.1094/PHP-2010-0408-01-RS.
• Biggs, A. R., Cooley, D. R., Rosenberger, D. A., and Yoder, K. S. 2010. Relative susceptibility of selected apple cultivars to sooty blotch and flyspeck. Online. Plant Health Progress doi:10.1094/PHP-2010-0726-01-RS.
• Sugimoto, T., Watanabe, K., Yoshida S., Aino M., Furiki, M., Shiono, M., Matoh, T., and Biggs A. R. 2010. Field experiments with two calcium compounds that reduce Phytophthora stem rot disease of soybean, and calcium distribution in plants using scanning electron microscope analysis. Plant Disease 94:812-819.