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The UVM Apple Team

Dr. Lorraine Berkett, Terence Bradshaw, Marlys Eddy

The UVM Apple Program:

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

Vermont Apple IPM Focus

2005 Degree Day Accumulation for Apple Scab Ascospore Maturity

2005 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
Date	4/19 (GT)	4/19 (GT)	4/20 (GT)	4/15 (GT)
4/16	-	-	-	14
4/19	23	19	-	88
4/23	84	88	57	164
4/27	156	158	129	232
4/30	202	206	175	281
5/04	254	255	227	331
5/07	301	301	276	375
5/10	367	369	344	436
5/14	447	453	422	527
5/21	581	586	556	671
5/29	762	763	736	839
6/04	962	958	939	1025

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, 2005", 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