Apple Pest Report:  Wednesday, April 30, 2003 

Vol. 11 No. 1

Budstage        
        In the Sanford area, 50% Green Tip (when green tissue is just visible on half the buds when looking from the side) was reported on April 21.  At Highmoor Farm in Monmouth, the date was Sunday April 27, about 3 days behind the average date. 

        Here are estimated budstage dates for Monmouth (Highmoor) and Sanford-area McIntosh trees in 2003:

McIntosh Bud Stage	Estimated date Sanford	Estimated date Monmouth
Half Inch Green	April 29 observed	May 2
Tight Cluster	May 7	May 10
Open Cluster	May 10	May 14
full Pink – extended	May 13	May 17
King Bloom	May 18	May 23
Full Bloom	May 19-20	May 24-25
95% Petal Fall	May 25	May 30

 
Apple Scab    

        The rain forecast for Thursday–Saturday May 1–3 will probably create only minimal scab infection risk in the Monmouth area because of little green tissue showing and ascospore maturation just getting started.  Bud stage is more advanced in the Sanford area, providing more target area for scab spores to land on, and thus higher infection risk.  But even in Sanford, a May 1–3 infection period would be RELATIVELY insignificant.  

        But RELATIVE is the key word.  In an orchard with heavy scab last year, ANY amount of infection risk is too much.  Scab is all about percentages.  A May 1-3 infection period would likely constitute only about 2% of the season's total scab infection pressure in both Monmouth and Sanford.  In a relatively clean orchard, trees can left unprotected for a low-pressure early infection period such as this.

        The question, as always, is "How much overwintering scab inoculum is there".  The fall scab indexing procedure provides that answer.  If you do not have that information, then the prudent choice is to assume there is too much scab to allow any unprotected infection periods.

        There is increasing concern and evidence of the scab fungus developing resistance to sterol inhibitor (Nova, Procure, Rubigan) and strobilurin fungicides (Flint, Sovran).  Because this resistance may be tied to the number of lifetime applications in a given orchard, plant pathologists I have spoken with in the past two weeks have agreed with the following statement:

"Scab management programs should be based on protectant fungicide applications.  Post-infection fungicides should be held in reserve for use only in those situations where coverage was inadequate prior to an infection period and their post-infection activity is the only recourse"

        In other words, don't plan on using post-infection fungicides.  To preserve their unique "kickback" activity as long as possible,  use them only when you are in a jam and need that activity.

        Captan is the best protectant fungicide available when you are not applying oil.  Polyram offers zinc micronutrient and oil compatibility for early use.  

        Syllit and other EBDC fungicides are also good protectants that are compatible with oil combination.  They can have some detrimental effect on predatory mites that eat pest mites.  However, early season use does not induce those effects because the predatory mites do not become active until after Tight cluster. 

 

 

Insects and Mites
        Prebloom is the easiest time to apply Lorsban to trunks to get season-long suppression of Dogwood borers and Roundheaded apple tree borer.  This is especially important for young trees on rootstocks prone to burr knots. 

        Removing white plastic trunk guards is also recommended.  Instead of replacing them in the fall, consider switching to hardware cloth as a vole guard.  Hardware cloth allows better air circulation around the trunk.

         It is still too early to spray for tarnished plant bug in the Monmouth area.  I am running out the door to set traps at Highmoor.  The traps are not perfect, but they do give good information to help in deciding if an insecticide application is need at Tight cluster - Pink.

2003 Apple IPM Program Sign Up Sheet
       You can find weather, disease and insect pest forecasts for Highmoor Farm in Monmouth at
http://pmo.umext.maine.edu/apple/AllModels/MEmodel/RadarME-Monmouth.htm

      The following Extension IPM Program resources are available to assist your pest management decisions in 2003. 

1) Apple Pest Report newsletter
        You are obviously already on the list for the email version.  If you would like to receive the Apple Pest Report newsletter by first class U.S. mail, the cost is $15 (check made out to Cooperative Extension) to cover mail and printing.

Name:
Mailing address:

        The Apple Pest Report will be posted at the Apple IPM website at time of mailing. 

2) Scouting Visits
        No-cost scouting visits will be available in 2003 for a limited number of orchards.  The scout leaves a report of observations, but does not make management recommendations.  The scouting service is made possible by subsidy from the Cooperative Extension Pest Management Office and the Maine State Pomological Society.  We fit as many locations into the route and visit most, but sometimes not all, of the growers who sign up.

Name:
Mailing Address:
(plus location of orchard if different than mailing address)
Telephone (and email if you have it)
Number of hours requested per week:

 

3)  2003 edition of the New England Apple Pest Management Guide
            The printed books are not expected to arrive from Massachusetts until mid-May at the earliest.  When they do arrive, they will be sold through Highmoor Farm.

 

4) The Apple Pest Hotline message will be at the same number as last year:  581-3898 starting May 2.  The hotline message is a quick  summary of scouting observations from the past week and management reminders for the week ahead.

 

Sincerely,
Glen

       Where brand names for chemicals are mentioned, no endorsement is implied nor is discrimination intended against products with similar ingredients.  Consult pesticide product labels for rates, application instructions, and safety precautions.  The label is the law.  Disregard any statements in this newsletter that appear to contradict label instructions.  Users of pesticide products assume all associated risks. 
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