apple.gif (24166 bytes)

The UVM Apple Team

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

uvmlogogreenwhite.gif (6745 bytes)

 

The UVM Apple Program:

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

imageextapple.gif (4123 bytes)

Vermont Apple IPM Focus

  L.P.Berkett, IPM Specialist


2008 Degree Day Accumulation for Plum Curculio Oviposition

Timing Insecticide Sprays using a Predictive Model

 

2008  Estimated Degree-Day Accumulation (Base 50F, from 95% McIntosh Petal Fall Date) for Selected Sites

Date

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

95% McIntosh Petal Fall Date

5/17 5/14 5/19 5/20

5/25

57 66 25 30

5/31

82 125 90 101

6/08

201 246 196 219

6/14

327 373 322 381

Date for 308 dd base 50 from 95% PF

6/14 6/10 6/14 6/12

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

Beginning at petal fall, cumulative heat units are recorded using a base temperature of 50F. Daily heat units can be calculated as (Max+Min)/2-50 where Max and Min are maximum and minimum temperatures. If this quantity is less than zero, no heat units are accumulated. Daily heat units are summed beginning at petal fall and no further insecticide applications are required provided the last insecticide was applied no later than 10 to 14 days prior to the date when summed units reach 308. Note that thisdegree day threshold is different than the recommended value in the past.   Entomologists at Cornell have revised this value to reflect a correction in the metric to SAE conversions used (http://www.nysaes.cornell.edu/ent/scaffolds/2005/050516.html).

Click here for information on this pest.

 

 


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

Back to Vermont Apple IPM Focus home page