Using Maryblyt to Manage Fire Blight in NY Deborah I. Breth Cornell CooperativeExtension Lake Ontario Fruit Program
Tree Fruit Industry in NY 42,360 acres of apples, 697 farms, 9.5 M trees, to produce ~ 30 M bushels of apples. 1700 acres of peaches, 48 acres of nectarines, 266 farms 1200 acres of pears, 255 farms 1688 acres of tart cherries, 141 farms 689 acres of sweet cherries, 194 farms 185 acres of plums, 128 farms 80 acres of apricots, 56 farms
Major varieties: Varieties *FB susceptible McIntosh, Empire, Delicious, Rome*, Cortland*, Gala*, Idared*, Golden Delicious* Miner varieties: Honeycrisp*, Gingergold*, Autumn Crisp*, Crispin*, Jonagold*, Macoun*, Fuji* 50 % Fresh: 50% Process
Rootstocks M9*, Bud. 9, G.16, G16 G. 41 M26*, G.11, G. 202 G. 30, G. 935 M7* M9/106* or 111* MM106 MM 111 Seedling 2006 NY Fruit Tree and Vineyard Survey
New Plantings of 1200 trees per acre Tall spindle system
Old Plantings of 50 trees per acre
Situation in NY No streptomycin resistance except 2 3 streptomycin sprays per season during bloom Growers with the most problems are processing growers planting new fresh fruit orchards, varieties and rootstocks susceptible to FB. New plantings can suffer 75% infection rates, and young plantings have suffered 50% tree loss with rootstock blight. Integrated processing orchards with fresh high value orchards results in ready supply of bacteria to infect new plantings.
Managing Fire Blight in NY Rainfall average annual precip 34 inches Compared to Salt Lake City, UT 14 inches Avg RH% in May and June 75 in AM, 55 in PM Compared to UT 55 in AM, 35 in PM Dew periods? Morning fog off lake or dew is common in spring. No measurable precipitation but leaves and blossoms are wet.
Maryblyt TM Computer based model, began in DOS version Updated to Windows version Maryblyt 7 Assumes the abundance of inoculum Predicts potential risk of infection based on the occurrence of certain conditions in sequence Predicts the development of symptoms http://www.maryblyt.com
Requirements for Blossom blight infection must have open blossoms bacteria only live on flower stigmas that are 3-4 days old accumulation of at least 198 DH>65F wetting event, dew or rain (.01 or >.1 the day before reaching DH threshold) for a continuous film of water to wash the bacteria from the stigma to the nectaries average daily temperature at least 60F? Maryblyt model.
Weakness # 2 Risk vs. Severity? Zoller and Sisevich, 1979
The risk of infection is not a prediction of severity, only that an infection event is likely. 3-5% of open blossoms are colonized at threshold of 198 DH(65), EIP = 100. At 30% bloom, 1-2 flowers open, EIP of 300 or 600 degree hours will quickly increase to 20% spur loss. At 60% bloom, and an EIP of 350 or CDH of 700 will result in 50% spur loss.
Creating a New Season File To create a new season file, press the Start new season button. The following dialog will appear:
New season: Click Add or Modify data
Program Menu Commands Menu Command Save/Save As Print/Print Preview Export to CSV... Description Saves the current data to a MARYBLYT file (*.mb7). Prints the grid data. Exports all data in the grid to a comma-delimited text file. Season Information... Shows the Season Information dialog. Set Thresholds... Display Metric Units Shows the Program Thresholds dialog, allowing thresholds to be changed. Refer to the Program Thresholds section for details on changing program thresholds. When checked, displays units in metric, otherwise units are displayed in US.
Main Toolbar Commands Toolbar Command Save Screen As Image View Graph Add or Modify Data Prediction Mode Description Saves a screen capture of the document window to an image file. Shows or hides the graph pane from the bottom of the document window. Enters Data Entry Mode, allowing data to be input into the grid. Enters Prediction Mode, allowing data to be input into the grid. Any changes to data are discarded when Prediction Mode is exited.
Graph Toolbar Commands Graph htoolbar Description Command Choose Data Copy Graph Save Graph as Image View Graph in Separate Window Selects graph items to be displayed. Copies an image of the graph to the Windows clipboard. The copied image can be pasted in another application such as a word processing program or image editing program. Saves a picture of the graph to an image file. Shows the graph in a separate window that can be maximized or resized.
Entering Data into MARYBLYT (Data Entry Mode) To enter new data or modify the existing data, press the Add or Modify Data button. MARYBLYT will enter Data Entry Mode, allowing data to be entered into Inputs section of the grid. After the desired data has been entered, press Accept Changes to accept the data or Discard Changes to cancel the data entry. When finished entering data, the season information must be saved. To save the file, select Save or Save As from the File menu, or press the Save button.
Maryblyt TM Output for BB DH EIP B H W T R DH = Degree hours accumulated EIP = Epiphytic pp Inoculum Potential B = Blossom present H = Degree hour threshold met W = Wetting event T = Average temperature of 60F R = Risk prediction
Maryblyt Risk prediction DH EIP B H W T R 144 73 + - + + H 216 109 + + + + I 144 73 + - + - M 408 206 + + + - H 264 133 + + - - M 168 85 + - - - L L =+ M =++ H = +++ I = ++++
Making Predictions with MARYBLYT (Prediction Mode) Prediction mode is useful for experimenting with data that is not intended to be saved. All changes made to the data while in Prediction Mode are discarded when Prediction mode is exited. Press the Prediction Mode button to enter Prediction Mode.
Prediction of Symptoms Blossom blight: 103 CDD>55F after predicted infection Canker blight: 196 CDD>55F after green tip Shoot blight: 103 CDD>55F after BB or CB symptoms Trauma blight: 103 CDD>55F after late frost, wind, hail Rootstock blight: 2-4 weeks after blight symptoms develop in scion, or following season?
Maryblyt is not a black/white model Thresholds can be changed for temperature after infection DH requirements can be lowered Life of flowers can be lengthened Critical factors are EIP or CDH using highest predicted temperatures, and bloom status Growers need to assess wetting potential on farm, and if only missing T, SPRAY!
Program Thresholds The MARYBLYT prediction model uses several parameters, or program thresholds, to generate its output. These program thresholds h are accessible from the Program Thresholds and Advanced Thresholds dialogs. Modification of these thresholds is considered advanced usage of MARYBLYT, and detailed descriptions of the thresholds can be found in the accompanying MARYBLYT documentation.
Summary Model output is only as good as weather and biological data input. Risk based on proximity to source of infection Risk based on susceptibility of variety and rootstock If approaching threshold, and variety and rootstock are highly susceptible, be more conservative in interpretation. Don t underestimate the possibility of some wetting event short shower, or dew, or spray
Keyboard Command Arrow Keys (Up/Down/Left/Right) HOME END ENTER Description Move to the adjacent cell. Holding Shift while moving will allow selection of multiple cells Move to the first row. Move to the last row containing data. Accept input in the current cell and move to the next cell. Pressing ENTER in the DATE column will automatically fill in the next record's date or the current date if it is the first row. TAB F2 DEL/Backspace CTRL-C CTRL-V CTRL-A Accept input in the current cell and moves to the next cell Edit the existing information in the current cell. Clear the data from the selected cells. Copy data from selected cells to the Windows Clipboard Paste copied data into grid, starting at selected cell. Select all cells.