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Bud stages by goodbaby

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									Apple Pest Report: Monday, April 21, 2008
Vol. 16 No. 1


      Welcome to another spring! Proof that life continues, past errors are
forgiven, and each day is a new beginning! This is the first 2008 issue for
the Apple Pest Report newsletter. I’ll be sending reports about once a week
during primary scab season which usually lasts until shortly after petal fall in
the beginning of June. After that the interval between reports will be longer
depending on what is going with different pest threats.

      Please do not hesitate to send observations or perspectives that you
think might be useful for the community of over 200 commercial and
hobbyist apple growers who subscribe to this newsletter.

Bud stages
      Orchard Radar is up and running at
http://pronewengland.org/AllModels/DecisionModels.htm Thanks to the
generosity of the Maine State Pomological Society, we have two sites this
year, Monmouth and Sanford. Monmouth is between Augusta and Lewiston
and is home of the University of Maine Highmoor Farm Agricultural Research
Station.

     Here are the estimated budstage dates for Monmouth and Sanford:
          Stage                  Sanford               Monmouth
    Half Inch Green               April 24               April 26
      Tight Cluster               April 30                May 5
      Open Cluster                 May 5                  May 9
  Full Pink - extended             May 9                 May 13
       King Bloom                 May 16                 May 19
       Full Bloom                 May 18                 May 21
    95% Petal Fall                May 25                 May 27
   ~ 100% Petal Fall              May 26                 May 29
        Fruit Set                 May 30                 June 2
Apple Scab
      While 2007 provided good weather and a bountiful crop, there were
unpleasant amounts of scab in some orchards by the end of the prolonged
warm fall. The lack of severe low temperatures and consistent snow cover
may over the winter also contribute to higher levels of overwintering scab
inoculum this spring.

       Sanitation to reduce the number of overwintered scabby leaves
producing spring ascospores ideally begins in the fall, but can still be very
effective in the spring. Many growers flail mow to chop up prunings anyway,
so it may be practical to set the flail as close to the ground as possible and
add leaf shredding to the benefit from that trip through the orchard. While
an offset mower can reach many of the leaves in the tree row, an offset
herbicide spray nozzle can reach leaves directly under the tree in the tree
row with a 5% urea solution (42 pounds urea per 100 gallons water, applied
at 100 gallons per sprayed acre to soak the leaves).

       My guess is that urea is still worth doing even at this date as most of
the microbial degradation of leaves that is accelerated with the addition of
urea occurs as temperatures warm in the spring. Flail mowing accomplishes
the same objective by creating greater surface area for leaf degradation, and
by flipping and shredding leaves into smaller pieces that work into the turf
such that released spores do not circulate into the airstream.

       There is only low probability of rain in the forecast out to Monday, April
28. Apple buds could be at Tight Cluster or beyond before we have the first
scab infection period. There is no need for fungicide protection if there is no
rain to allow scab infections to occur. A late start for scab protection can be
fully effective and save time and money. But in playing the waiting game,
consider what your reaction time will be if the weather forecast changes
suddenly. If you don’t think you can get the orchard protected in time to
respond to that scenario, a cautious approach would be to get some
protection in place when there appears to be any reasonable chance of rain

       A later start puts more pressure on the first application to get good
coverage. A typical protective fungicide program that begins with copper
shortly after green tip, followed by applications ahead of rains at Half Inch
Green and Tight Cluster, results in several doses of fungicide being applied
before the major scab spore releases that occur between Pink and Petal Fall.
While rain removes much of the fungicide from the earlier applications, there
is a cumulative effect of repeated applications and redistribution that
contributes to preventing scab infections during the time of peak scab
infection pressure. With a late start those earlier applications aren’t there
providing underlying support, the only protection you have is what was
applied in preparation for the first infection period. That’s not an argument
to go out and apply fungicide when there is no rain in the forecast. But it is
a caution to check out your spray delivery system ahead of time and make
sure equipment is calibrated and everything is working correctly before
heading into the main event without less intense early season disease
conditions to serve as a shake down cruise to discover and correct spray
delivery problems.

      It would be nice to think that in dry weather scab just dries up and
dies, but it doesn’t. Scab spores can wait it out until the rain does arrive,
and when it does there will be that many more of them ready to launch.

      Copper at green tip through quarter inch green acts as an excellent
fungicide, while also serving as a micronutrient, and helping to prevent the
spread of fire blight bacteria from overwintered cankers if there are any in
the orchard. Application at Half inch green or later increase the risk of leaf
burn or phytotoxicity to fruit if subsequent rainfall is not enough to remove
the copper before nascent fruit tissue becomes exposed during Pink and
Bloom.



Fire blight
      United Agri Products (UAP) in Lewiston is has a supply of Firewall
bactericide. This material is good to have on hand should hot weather
during bloom create conditions for fire blight blossom infections. Firewall is
approved for use in organic orchards.

       We normally don’t have blossom blight weather in Maine. Last year
we did. The outcome of those conditions was less than feared but there
were a few orchards that did have fire blight symptoms, enough to remind
us that there is some inoculum around. Fire blight remains a difficult to
predict disease for which concern and attention are due as highly susceptible
cultivars like Honeycrisp, Gingergold, Gala, Fuji and Jonagold replace less
(but still) susceptible cultivars like McIntosh, Cortland, and Golden Delicious.
Insects and Mites
   European red mite egg hatch is forecast for May 8 in the Sanford area,
and by May 11 in Monmouth. Oil applications should be completed before
then in order to have best effect.

      Even with oil prices escalating, prebloom oil remains a wise investment
for most orchards. The recommended rate is 2 gallons oil per 100 gallons
water from Green Tip through Half Inch Green (HIG), 1.5 gallons from HIG
to Tight Cluster (TC), and 1 gallon from TC to early Pink. Once trees reach
Pink stage, it is better to wait until after Petal Fall to evaluate the mite
population.

      The price of water hasn’t gone up like oil, and it is useful to remember
that water is a cheap miticide. While you can’t deliver the amount of water
needed to suppress mites in the way that heavy rains can, good spray
coverage is essential to get the best effect from oil application. So spraying
at no more than 3X concentration is (i.e. no less than 1/3 the dilute rate of
water per acre) is advised.




Other News
1. The 2008 New England Tree Fruit Pest Management Guide is
available from Highmoor Farm for $20 mailed, or $15 if you pick it up.
There were extensive revisions from last years editions to incorporate new
pesticide registrations and to continue the adaptation of the New York guide
for use in New England.

2. With support from the Maine State Pomological Society and USDA-APHIS
(Animal and Plant Health Inspection Service), Cooperative Extension will
operate the orchard scouting co-op and conduct a baseline trapping
survey for several key apple feeding caterpillar species. If you are already
on the orchard co-op list you receive an email message just prior to this
edition of the Apple Pest Report. If you did not receive a confirmation
message and would like to be on the scout route, please send an email to
gkoehler@umext.maine.edu. Participating orchards must have at least one
acre of commercial orchard. Due to limited resources and travel constraints
we are not able to service all interested, qualified orchards, but we try to fit
in as many as we can.
3. An orchard twilight meeting is being planned for June 4 in southern
Maine. A twilight meeting at Highmoor Farm is being planned for June 11.
Details to follow

4. The TRAC pesticide application recordkeeping software published by
Cornell, updated for 2008, is now available for free! You can download it at
http://www.nysipm.cornell.edu/trac/downloads/. There are versions for
apples, pears, stone fruit (peach, nectarine, plum), cherries, grapes, and
berries, along with user manual. You will need to have Microsoft Excel for
Windows to use the program. TRAC will not work if you are using the 2008
version of Excel for Apple computers (Office for Mac).

5. The 238-page “Tree Fruit Field Guide to Insect, Mite and Disease Pests
and Natural Enemies of Eastern North America” is available from Highmoor
Farm for $20 mailed, or $17.40 if you pick it up. This is a great book to
have on hand to identify the less common insect and disease symptoms that
pop up in tree fruit plantings.

6. Quick Identification Guide to Apple Postharvest Defects & Disorders, is a
color, laminated, 36 page guide of 4” X 6” cards held together in a ring that
can allow new cards to be added. It was compiled by entomology,
horticulture, and plant pathology experts at Washington State University.
The cards have photo and text descriptions of arthropod damage, diseases,
physiological disorders, mechanical/field injury, and fruit finish
defects/disorders. Useful to have on hand in packinghouses. Cost is $30.
Contact Craig Kahlke at 585-735-5448 or cjk37@cornell.edu\

7. Not Far from the Tree: A Brief History of the Apples and the Orchards of
Palermo, Maine, 1804-2004 was written by Maine’s own John Bunker. This
is a 200 page, 8-1/2 x 11, softcover book. You can read about it at
http://morningsentinel.mainetoday.com/news/local/4702157.html,
and you can buy it at:
http://www.mofgastore.org/product.sc;jsessionid=4081286F289CCB542E784122968EE
C22.qscstrfrnt03?categoryId=7&productId=71

8. It’s never too early to arrange for bee hives for pollination, especially this
year with increasing sugar and fuel prices adding more complications to the
beekeeping industry. For an interesting update on the Colony Collapse
Disorder, see the link below.
http://www.bangordailynews.com/news/t/city.aspx?articleid=162050&zoneid=176

								
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