Contents

Observations from Belchertown

Apple maturity report

Jmcextman blog posts

Getting the most from the "old" stop-drop: NAA

Observations from Belchertown

Apple harvest is genuinely underway with Jerseymac, Paulared, Sansa, and Zestar! being picked. Seasonal -- or slightly below -- temperatures and fair skies are far more than what we could have asked for. (We deserve it after a month of rain.) I expect harvest of earlier strains of McIntosh, including Marshall and Lindamac to begin this week. See my apple maturity report below for more details. If temperatures stay cool we may be in full-swing McIntosh harvest next week. It's probably not too late to apply ReTain to Macs that will be harvested after mid-September, and Gala might still benefit from a shot of ReTain to even out maturity.

Peach harvest is probably at it's peak or declining. Redhavens are just reaching optimum maturity, which seems a little late. Again, the fair weather has benefitted peach harvest operations.

J. Clements

Apple maturity report

Below are some of my observations on apples we are harvesting in Belchertown. All-in-all, I don't see any huge departures from a 'normal' harvest. I will say color looks good overall, and you should start to be alert for signs of drop in McIntosh and Honeycrisp. (See article below on using NAA 'stop-drop.') I also expect to see more watercore than usual, given the large fruit size and excess water we have had in the past month. I'm also thinking maturity will be a little uneven between varieties, so be on your toes.

Harvest date: 23-August

Harvest date: 26-August

Jmcextman blog posts

TUESDAY, AUGUST 19, 2008
4 rules for pruning tall-spindle apple

Getting the Most From The "Old" Stop-Drop: NAA

by Jim Schupp, PhD.
Specialist in Pomology, Penn State University
Reprinted from Scaffolds Fruit Journal
August 18, 2003 Volume 12 No. 23
http://www.nysaes.cornell.edu/ent/scaffolds/
Edits by Win Cowgill, County Agricultural Agent NJAES, and again reprinted from Rutgers Cooperative Extension Plant & Pest Advisory, Fruit Edition, August 19, 2008

The use of NAA (Fruitone N, L; K-Salt Fruit Fix) for control of preharvest drop has been overshadowed in recent years by that of ReTain; however, ReTain use must be planned weeks prior to harvest. With the effective application time so close to the onset of drop, NAA offers a "rescue" treatment, should the threat of preharvest drop be increased due to unforeseen circumstances. Examples of such situations include unavoidable delays in harvest due to bad weather or labor issues, slow red color development, and overlapping harvest schedules of varieties with similar maturity windows, such as McIntosh with Macoun, or Empire with Delicious. While it is not the purpose of this article either to promote or condemn the use of ethephon (Ethrel, Ethephon II) to promote fruit coloring, those growers using one of these products also need to use NAA to prevent excessive fruit drop resulting from accelerated fruit maturation. The following tips and reminders are offered to help growers brush up on using NAA to best effect.

Timing NAA stop-drop sprays is a little like a game of chicken, requiring both steely nerves and a good understanding of your opponent. The label says to apply NAA when the first sound fruit begin to drop. A single spray of 10—20 ppm NAA offers drop control for about seven days from the date of application, but it takes two or three days to "kick in". Apply NAA three days too early and the window of effective drop control is about halved. Apply three days too late and perhaps a quarter of the crop will be on the ground before the NAA takes effect!

Stem loosening coincides with the climacteric rise in ethylene that signals fruit ripening. Unlike ReTain, which delays drop by delaying fruit maturation, NAA stops drop by delaying stem loosening.

Varieties such as McIntosh that are highly susceptible to preharvest drop require careful monitoring to determine when fruit drop is beginning. Limb tapping should be used to determine the onset of drop as fruit near maturity. Bump several scaffold limbs of three or four inches in diameter throughout the block on a daily basis. Use the palm of your hand with a short firm stroke, striking the limb at its mid-point (just like golf, this skill improves with practice and experience). If zero to one apples per limb drop on average, it's too soon to apply NAA. If the average is about two, check again later the same day or the next morning. When several apples drop in response to limb bumping, its time to harvest within two days or apply NAA.

When NAA is used to control drop on ethephon-treated trees, the two may be tank-mixed if the fruit is to be harvested within seven days. If the fruit is to be left on the tree longer than seven days after the ethephon, then NAA should be applied three days after the ethephon.

Rates of 10—20 ppm NAA are usually needed to be an effective stop-drop. To obtain the maximum drop control, use a split application of 10 ppm in the first spray, followed by a second spray of 10 ppm five days after the first. Split applications can provide drop control for about 12 days from the date of the first application.

As with thinning sprays, stop-drop sprays of NAA work best when applied with good coverage and plenty of water. Concentrating beyond 4X (less than 75 gallons of water per acre for 300 gallon TRV trees) may diminish the effectiveness. Use a non-ionic or organosilicone surfactant to enhance uptake.

When used as a stop-drop, NAA may advance ripening, especially at the maximum label rate of 20 ppm. The primary impact of his advance in maturity is reduced storage potential of the fruit, particularly in the loss of firmness. This effect is not consistent from year to year or block to block. The question then arises whether NAA-treated fruit has potential for CA storage or treatment with SmartFresh (1-MCP).
(Editors Note: this loss of firmness is not an issue on PYO blocks or fruit held for short term storage.)

Retain and NAA - Finally, a comment about use of NAA on trees previously treated with ReTain. The use of both stop-drops at the respective correct times results in drop control that is superior to that obtained by using either one alone. Fruit treated in this manner, then left for an extended time on the tree, often have limited storage potential (see above); however, this combination can be an effective way of getting the ultimate in drop control. This drop control combination program should be used on high value fruit with little or no storage period, such as for a few rows of trees held for late picking in PYO blocks or on McIntosh that Retain alone may not be as effective as we like.

Retain -If you missed your Retain application timing of 4 weeks before anticipated harvest you can still apply Retain up to 7 days PHI. This will hold the second and later pickings on the tree. You may need to use NAA as well to hold the first ripening fruits on the tree. Consult the label for more details.

Note: the next Healthy Fruit will be published on or about September 10.