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The UVM Apple Team

Dr. Lorraine Berkett, Dr. Elena Garcia,  Terence Bradshaw, Jessica Reardon, Linda Boccuzzo, and Karl Zahn

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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

2000 DD Accumulation for

Apple Scab Ascospore Maturity

2000  Estimated Degree-Day Accumulation (Base 32F, from McIntosh Green Tip) for Selected Sites

Date

UVM Hort.Res.Center (GT= 04/08)

Shoreham (GT= 04/15)

New Haven (GT= 04/08)

Bennington (GT= 04/05)

Saxtons River (GT=04/11)

Franklin (GT= 5/2)
04/16 82 45 45 111 60 Not Avail
04/19 112 75 75 140 90 Not Avail
04/23 159 126 166 186 134 Not Avail
04/25 175 144 182 205 150 Not Avail
04/29 222 190 227 240 182 Not Avail
05/02 267 236 271 282 222 14
05/03 282 251 286 297 236 28
05/07 410 383 415 422 354 143
05/09 476 457 486 503 430 203
05/13 569 555 576 598 517 288
05/15 609 593 617 633 552 328
05/17 647 632 655 670 589 366
05/21 721 707 728 742 661 437
05/25 826 811 832 835 751 539
05/28 898 885 906 903 823 606
05/30 946 934 955 946 866 652
06/04 1097 1088 1107 1091 1011 794
06/07 1159 1152 1170 1151 1070 853

Please use the following chart to Estimate Ascospore Maturity

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

Cumulative

90%

Degree Days2

Ascospores

Confidence Interval

Matured (%)

for Estimate3

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 "Pest Management Recommendations for Commercial

Tree-Fruit Production, 1999", Cornell Cooperative Extension Publication.

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 to:  lorraine.berkett@uvm.edu

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