Apple insect pest degree day models

Background Information for this page
Return to radar list for South Burlington VT
Weather data for South Burlington VT.  Forecast values begin May 19, 2013
 
Borers  -  Roundheaded Appletree Borer (RAB)   &   Dogwood Borer
RAB egglaying begins:  September 22.    Peak egglaying period roughly:  September 22  to September 22. 
First RAB eggs hatch roughly:  October 7.    Peak hatch roughly:  October 7  to October 12.
First Dogwood borer egg hatch roughly:  October 1.    Peak hatch roughly:  October 12.
Codling Moth  (CM)
Too early for CM status report
1st generation 3% CM egg hatch:  October 1,  Tuesday,
= target date for first spray where multiple sprays needed to control 1st generation CM.

See Codling moth tables for follow-up spray dates to maintain protection
through 1st generation CM egg hatch.
1st generation 20% CM egg hatch:  October 1,  Tuesday,
= target date where one spray needed to control 1st generation CM.
2nd generation 7% CM egg hatch:  October 1,  Tuesday,
= target date for first spray where multiple sprays needed to control 2nd generation CM.
    If needed and allowed by preharvest interval,
see the August Codling Moth table for follow-up spray dates.
2nd generation 30% CM egg hatch:  October 1,  Tuesday,
= target date where one spray needed to control 2nd generation CM.
Lesser Appleworm   LAW 
1st LAW flight begins around:  May 14,  Tuesday.          Peak trap catch:  May 25.
2nd LAW flight begins around:  September 22,  Sunday.
Mullein Plant Bug   MPB 
The expected 50% egg hatch date is:  May 18,  Saturday,
which is 5 days before rough estimate of Red Delicious petal fall date.
Most accurate time for limb tapping counts, or treatment if needed,
but possibly after some MPB damage has occurred,
is 90% egg hatch date:  May 23,  Thursday.
Obliquebanded Leafroller   OBLR 
1st generation OBLR flight begins around:  September 22,  Sunday.
Where waiting to sample late instar OBLR larvae is not an option
(= where OBLR is known to be a problem,
and will be managed with insecticide against young larvae):
Early egg hatch and optimum date for initial application of B.t., Delegate, Proclaim, Intrepid, Rimon, Altacor, Belt, pyrethroid or other insecticide effective against OBLR
(with follow-up applications as needed):  September 22,  Sunday.
Where waiting to sample late instar OBLR larvae to determine need for treatment
is an option, or to check on results from earlier sprays:
Optimum sample date for late instar summer generation OBLR larvae: September 22,  Sunday
If first OBLR late instar larvae sample is below threshold, date for confirmation follow-up:
September 22,  Sunday.
Oriental Fruit Moth   OFM 

1st generation OFM flight starts:  May 7,  Tuesday.
1st generation 55% egg hatch and first treatment date, if needed: September 1,  Sunday.
2nd generation OFM flight begins around:  September 22,  Sunday.
2nd generation - first treatment date, if needed: May 27,  Monday.
2nd generation - second treatment date, if needed: September 1,  Sunday.
Plum Curculio   PC
 Increased risk of PC damage as McIntosh and similar cultivars increase fruit size:
 May 24,  Friday.
 Earliest safe date for last PC insecticide spray:  June 29,  Saturday.
Plum curculio spray intervals
 If relying on repellance by Surround instead of PC mortality by insecticide,  Surround coverage should be maintained until PC egglaying begins to naturally decline around Saturday, June 29.
Redbanded Leafroller   RBLR 
1st RBLR flight begins around April 25,  Thursday.
  Peak trap catch and approximate start of egg hatch: May 7, Tuesday.
2nd RBLR flight begins around September 22,  Sunday.   
Peak catch and approximate start of egg hatch: September 22.
San Jose Scale   SJS
First adult SJS caught on trap:  May 23,  Thursday.
1st generation SJS crawlers appear:  September 22,  Sunday.
Spotted Tentiform Leafminer   STLM
(and presumably apple blotch leafminer)
1st STLM flight, peak trap catch:  January 1,  Sunday.
1st generation sapfeeding mines start showing:  May 24,  Friday. 
Optimum sample date is around Saturday, May 25,
when a larger portion of the mines are visible.
2nd STLM flight begins around:  September 22,  Sunday.
Rough guess of when 2nd generation sap-feeding mines begin showing:  September 21,  Saturday.  
Optimum first sample date for 2nd generation STLM sapfeeding mines is
September 21,  Saturday.
Second optimized sample date for 2nd generation STLM sapfeeding mines, if needed:
September 22,  Sunday.
Third optimized sample date for 2nd generation STLM sapfeeding mines, if needed:
September 22,  Sunday.
Tarnished Plant Bug    TPB 
Rough guess of when TPB begin showing on traps:  May 18,  Saturday.
Rough guess of when TPB damage results in deformed fruit at harvest
 instead of aborted bud: May 7,  Tuesday.
White Apple Leafhopper   WAL 
1st generation WAL found on apple foliage:  May 16,  Thursday.
2nd generation WAL found on apple foliage:  September 22,  Sunday.
* Rose leafhopper is easily confused with WAL but has different generation dates.
Rose leafhoppers typically immigrate into orchards from border row host plants
between 1st and 2nd generation WAL.