Even though, I am retired from Virginia Tech, this might be a subject your
readers might like to pursue.
I woke up this morning (about 5 am) thinking of the freeze out in southern
Indiana, and the huge pruning job facing my brother, David, at Applacres in
2007-2008. It occurred to me that there are a few things that might make
sense with a complete freeze out in 2007 where vigors tree growth will
likely be a huge problem in 2008 (close plantings, vigors rootstocks, no
crop or very little).
In one experiment some years ago, we used 6 reduced rate Apogee (63ppm)
+Ethephon (135ppm) + NH3S04 + Choice (a surfactant /penetrant) applications
starting at petal fall about 3 week apart . Tree growth (as shoot length
of the longest shoots) was reduced to less than 60% of the
Controls. Although we did not measure effects on shorting shoots, shoot
length and shoot weights were likely much greater. The research paper has
been going from editor to editor for over 2 years now and I really do not
know the status of it. Publishing is not now on my short list of things to do.
The Ethephon reduces the cost of the plant growth regulator combination ,
and the ethephon has a longer lasting effect on reducing shoot growth than
Apogee, but it increases flowering and will cause thinning of fruit above
the 135 ppm level with some cultivars.
Higher rates of ethephon will have a dramatic effect on shoot growth at
increasing rates so if thinning is not an issue (due to the loss of crop)
270 ppm or higher rates might be used in this combination. To further
reduce the cost Ethephon might be used alone . The reduced crop trees will
flower heavily next year anyway, but Ethephon will further increase
flowering so early fruit thinning will be a must in 2008. (Gibberellins
can not overcome the increased flowering and will increase shoot growth so
that approach will not work, in my opinion in a low crop situation).
I have some photographs of the retarding effect of Ethephon + Apogee and
will try to post them later.
If vigors tree growth after a freeze is a subject that is of interest to
you, be aware I do not check e-mail every 10 min anymore due to all the
spam. I check more like every 3 weeks and I also expect to be changing my
email address soon.
At 11:09 AM 4/11/07 -0400, you wrote:
At our research farm near Winchester, VA our low Sunday morning was
26. Lows the previous nights were 29 and 27. There was some wind each of
those nights. The most advanced cultivars, such as Idared and Red
Delicious, were showing some early pink at the higher elevations, but were
not yet at open cluster. Peaches were near full bloom.
I see damage to some king bloom of earlier cultivars, but at this point
would say there is still the potential for a full crop of apples on our
trees. The peaches still have enough live flowers to make a full crop, but
I will reserve judgment on them because I think the miserable pollination/
fruit set conditions might be as much of a factor as the freeze in final
fruit set in our situation.
Yesterday we visited an orchard in central Virginia, south of
Charlottesville, which also has the potential for a full crop in spite of
cold and windburn on petals of open bloom and flower cluster leaves.
Reports from farther south in Virginia are generally less optimistic, with
colder temperatures and more advanced bud stage than we had in the
Winchester area. I am reminding those who are more pessimistic of a
situation I observed some years ago where Golden Delicious trees responded
to an apparent frost wipe-out with stimulated shoot tip bloom about two
weeks later that developed into a good crop!
Keith Yoder
Research and Extension Tree Fruit Pathologist
Va. Tech Ag. Research and Extension Center
595 Laurel Grove Road
Winchester, VA 22602
At 05:17 PM 4/10/2007 -0400, you wrote:
A week ago we were setting record highs in the mid 70s and apricots were in
full bloom. Frigid weather arrived on Wednesday with snow and highs near
freezing for the next four days. We had low temps in lower 20's with a wind
for 6, 8 and 12 hours on successive days. Lows near 20 occurred on Friday
and Saturday mornings. Low temperatures were a few degrees higher close to
Lake Michigan and the extreme cold did not last as long so they fared better
but away from the Lake we got hit hard. We are not wiped out but many fruit
crops were damaged by the freeze. It seems obvious to me that the entire
eastern half of the nation has been hit hard and that fruit crops here in
the east will be scarce, and a lot of growers will be looking to supplement
their income.
Does anyone south of Michigan have any fruit left?
How are things in New York and New Jersey?
The MSU Fruit Crop Alert Letter was posted today with initial reports from
Michigan
http://www.ipm.msu.edu/cat07fruit/f04-10-07.htm
-----------------------------------------
Mark Longstroth
SW Michigan District Fruit Educator
Van Buren County MSU Extension
801 Hazen Street, Suite A
Paw Paw, MI 49079
Bus (269) 657-7745
Fax (269) 657-6678
Email - [EMAIL PROTECTED]
Check Out My Webpages
http://web1.msue.msu.edu/vanburen/disthort.htm
-----------------------------------------
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