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Healthy Fruit 2010 Vol. 18:19

Sep 21, 2010

The way I see it

Sitting here on a cool morning I don't have much to say, other than the fact it has generally been a great stretch of weather to get the apple harvest in. I am not sure we could ask for much more consistency in relatively cool nights -- it dropped down to 41 here in Belchertown last night -- and seasonal, sunny days. I sent out an apple maturity report last week which I will repeat here. If the next two weeks hold weather-wise, apple harvest should be 90% done. I wonder if there will be any apples left for Columbus Day weekend? JC

Apple maturity test results

In table-form below are results of maturity testing from apples picked at the UMass Cold Spring Orchard in Belchertown.

date Cultivar pre-harvest drop fruit diameter inches color % red firmness lbs soluble solids starch index comments
9/21/2010 Macoun significant 3.0 75 16.1 12.6 3.5 ready to start to pick
date Cultivar pre-harvest drop fruit diameter inches color % red firmness lbs soluble solids starch index comments
9/16/2010 Empire nil 3.0 70 17.5 11.2 3.4 need another week to pick
9/16/2010 Jonagold DeCoster nil 3.2 80 16.9 14.6 7.2 some watercore; 3rd leaf tall-spindle trees; quite ready to harvest by red color
9/16/2010 Delicious nil 3.1 98 16.6 13 3.2 (2-6.5) picking very easy; some watercore; ready to harvest next week for sure
date Cultivar pre-harvest drop fruit diameter inches color % red firmness lbs soluble solids starch index comments
9/15/2010 Redcort Cortland nil 3.3 85 15.5 11.6 3.1 (1.5-5) could be picked now
9/15/2010 Rising Sun Fuji none 2.9 60 13.1 11.7 7.2 heavy crop adverse affect on quality
9/15/2010 Blondee nil 2.95 NA 15.7 12.6 7.5 at end of harvest period
9/15/2010 Macoun some 3.2 65 still dull 16 11.8 3.5 not quite ready with full varietal flavor; wait another week

All harvested at UMass Cold Spring Orchard, Belchertown.

What is it?

San Jose Scale on Macoun

  1. ozone damage?
  2. sunburn?
  3. oh, it's typical Macoun! (Why DO people find this apple so great, anyways???)
  4. San Jose scale?

Ha-ha. If you chose 4. San Jose Scale, you are correct. We don't see much of this pest for several reasons. Usually only in unsprayed orchards, rarely in orchards that receive spring oil for mites, not particularly winter-hardy. But, I havejust found this damage in a managed orchard in Belchertown, that yes, has not had oil for several years now, and yes, last winter was mild. Why no oil? Well, there are rumors out there that oil has an adverse affect on productivity, and sometimes it is just a pain to get on at the right timing, etc. Mites have been a relative non-issue, easily cleaned up with a summer miticide if necessary. (None was necessary this year.) Interestingly too, this orchard has been extremely productive -- we just finished picking a thinning experiment on these Macoun apples that yielded-out to an equivalent of 1,750 bushels per acre! (The thinning treatments did not work too well.)

But Scale bothers me a bit, because left unchecked, can build up and cause tree damage, and result in this unsightly fruit. Options for control next year include resuming oil sprays, or using one of several insecticides (Lorsban, Esteem, Movento, Centaur). If anyone else is seeing more scale than usual, drop me a note. JC

Guest article—Foliar Nitrogen for Sweet Cherry Now for Increased Yields in 2011

Win Cowgill, County Agricultural Agent, Rutgers Cooperative Extension

Foliar applications of urea nitrogen have been shown to aid fruit size in sweet cherry and increase cold hardiness.

Dr. Greg Lang, Michigan State University reported on this work both at the International Fruit Tree Association Meeting in California and 2007 and repeated the work in 2008. Here are the details: The current suggestion to cherry growers is apply two fall foliar applications of low-biuret (spray) urea, applied at about 15 to 20 lbs per acre per application. Spray volumes have been as low as 50 GPA up to 250 GPA and with a curtain(tunnel) sprayer. Standard is probably 100 GPA. D.r Lang reports that they actually got the least amount of marginal leaf burn with the low volume since there was no pooling along the leaf margins.

The nitrogen application definitely increases the flowering spur N going into winter and can improve spur leaf size the next spring. This translates into larger fruit size.

The best timing is in earl September, with a second application two weeks later. They did application-timing research with applications made through October but saw the best increase in leaf nitrogen levels from the earlier treatments (September). The September applications were also best for improvement in cold acclimation. Dr. Lang Reports that this is just one year's data, but it was so strikingly consistent that he feels the mid-September through mid-October is looking more like the best window for Michigan growers. (They usually expect leaf senescence from Halloween through the 2nd week of Nov).

In New Jersey (and Massachusetts) we expect the same results depending on how well we have controlled cherry leaf spot and the nutritional status of the tree and leaves. At the Rutgers Snyder Farm I have applied 20 lbs urea/100 gallons, spraying at tree row volume dilute on both sweet and tart cherries with no foliar burn in late September, in 2008 and 2009. I will repeat this week and repeat in 10-14 days. In my cherry research plots at the Snyder Farm I also controlled cherry leaf spot through out the summer and fall months with regular fungicide applications and have also made my first application of Bordeaux mix (using Cuprofix and safened with canola oil) to control Bacterial Canker. I will make one more spay in September and two more in October. I would not suggest added nitrogen to the copper sprays as this is untested. I.e., they should be separate sprays.

Useful links

UMass Extension Fruit Program

Scaffolds Fruit Journal

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