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The UVM Apple Team

Dr. Lorraine Berkett,  Terence Bradshaw,  Sarah Kingsley-Richards, Morgan Cromwell

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The UVM Apple Program:

Extension and Research for the commercial tree fruit grower in Vermont and beyond...

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Vermont Apple IPM Focus

  L.P.Berkett, IPM Specialist


2010 Degree Day Accumulation for Apple Scab Ascospore Maturity

2010  Estimated Degree-Day Accumulation (Base 32F, from McIntosh Green Tip) for Selected Sites

UVM HRC

South Burlington Chittenden Co.

Elev. 71 M

    Shoreham

Addison Co.

Elev. 107 M

South Hero

Grand Isle Co.

Elev. 54M

Dummerston

Windham Co.

Elev. 171 M

East Dorset
Bennington Co.

Elev. 408 M

Green Tip Date 4/03 4/03 4/04 4/03 4/05
4/04 59 56 27 55  
4/10 180 187 141 192 100
4/17 268 2777 230 289 200
4/24 380 392 343 407 299
5/01 489 504 455 531 403
5/08 683 702 644 743 591
5/15 790 808 750 854 684
5/22 980 999 945 1045 860

Date for 900 dd

5/20 5/19 5/21 5/17 5/23

Degree Day and other weather information received from Skybit E-Weather Service: http://www.skybit.com/

 

Please use the following chart to Estimate Ascospore Maturity

Cumulative Percentage of Ascospores Matured at Various Degree Day Accumulations (Base=32 F)1

 

Degree Days (2)

Cumulative

Ascospores

Matured (%)

90%

Confidence Interval

for Estimate (3)

35

1

0-7

110

3

0-14

145

5

1-19

215

12

2-32

325

25

7-55

450

50

21-80

575

75

46-94

685

90

69-98

740

95

79-99

790

97

86-100

865

99

93-100

1-Table from 2010 New England Tree Fruit Management Guide

2- DD should be recorded from the date when 50% McIntosh fruit buds are between silver tip and green tip. The base temperature = 32F. Data of Gadoury and MacHardy, 1982.

3-The width of the 90% confidence interval is a statistical measure of the precision of estimated maturity. It is the range within which the estimate should fall 90% of the time.


Please send comments and suggestions tolorraine.berkett@uvm.edu

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