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The UVM Apple Team

Dr. Lorraine Berkett, Dr. Elena Garcia,

Terence Bradshaw, Chris Benedict

The UVM Apple Program:

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

Vermont Apple IPM Focus

L.P.Berkett, IPM Specialist

2003 Degree Day Accumulation for Apple Scab Ascospore Maturity

2003 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	Bennington Bennington Co. Elev. 370 M	Dummerston Windham Co. Elev. 171 M
Date	4/20 (GT)	4/21 (GT)	4/22 (GT)	4/16 (GT)	4/17 (GT)
4/26	103	79	47	157	131
4/28	143	118	87	195	171
5/03	233	215	175	300	286
5/10	371	352	312	428	427
5/17	518	495	462	558	563
5/25	727	698	673	737	753
6/01	909	878	856	907	934
6/07	1064	1033	1014	1054	1090

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 "Pest Management Recommendations for Commercial Tree-Fruit Production, 2003", 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