Scaffolds 01 index

(Jim Schupp,jrs53@cornell.edu, Horticultural Sciences, Highland)

The timing of the first Apogee application is critical to getting optimal growth control in orchards in northern states. This is because most of the annual shoot growth occurs in a relatively short, rapid burst in orchards north of the Mason-Dixon Line. Shoot growth begins about full bloom, quickly enters the phase of the most rapid growth, then gradually slows and usually ends by mid- to late July. To get the best growth control from Apogee, it must be applied before the start of the rapid growth phase.

It takes 10—14 days for Apogee to fully take effect, and a lot of the season's growth will have already occurred if the spray is late. Also, once shoots are rapidly growing, it seems to take a higher concentration of Apogee to get them under control. Observations suggest this last point is especially true with McIntosh.

The first Apogee application should be made when the new terminal growth is 1 to 3 inches long. This amount of growth often coincides with late bloom to petal fall, and we suggest that growers use petal fall to time Apogee applications. Growers do not have time to measure shoots, and are usually not attuned to how rapidly shoots are growing at this time of season. In short, if a grower waits until 3-inch long shoots are present to schedule an Apogee spray, then waits 2 or 3 days so that he can apply Apogee along with a scheduled pesticide spray, then waits a little longer to get good spray conditions, the results will be sub-optimal. Timing is everything. Apogee is non-toxic to bees; go knock off some petals with Apogee sprays!

The duration of growth control depends upon the dose and tree vigor. The Apogee label permits a wide range of dose options, from 3 to 16 ounces per 100 gallons, dilute basis. We suggest that growers select the dilute rate, then use the TRV calculations as outlined in Cornell Recommends to determine rate per acre. For New York conditions, 6—12 ounces of Apogee per 100 gallons dilute basis will provide growth control for trees of good-to-high vigor, respectively. The growth control at these rates will usually last 4 to 6 weeks. Lower doses may also be effective, but the response may last only 2 to 4 weeks.

Two well-timed sprays should provide season-long growth control in most orchards in the northeast. Excessively vigorous trees may require a third application to achieve season-long control.

One strategy for timing the second spray is the calendar method. Apply the second spray 2 weeks after the first. This is an effective strategy that involves the least time investment. For operations that are stretched thin on management, this may be the best strategy.

The other option is monitoring. Three weeks after the first spray, start scouting the orchard twice weekly. Monitor the longest shoots in the top of the canopy for new growth, and apply the second spray as soon as the first shoots resume growth.

Monitoring may provide the most growth control for the least cost. If growth control from the first spray persists, growers may be able to reduce the rate of the second Apogee spray and still achieve season-long control. It is important to leave a few untreated check trees in the block to compare the effect of Apogee and to gauge the need for the second spray.

Poor monitoring that fails to detect the first regrowth, or a slow response that fails to re-apply Apogee before shoot growth resumes will result in poor growth control. Continue to monitor shoot growth in excessively vigorous blocks to determine if a third spray is necessary, keeping the 45 day pre-harvest interval in mind.

How about spray volume? Apogee has performed well with a wide range of volumes. Use enough water to get thorough coverage for the size and density of the canopy being treated.

The suggested retail price of Apogee is $90 per pound, equal to $5.63 per ounce. If a grower has a block of trees with tree row volume of 200 gallons per acre and decides to apply 6 ounces per 100 gallons dilute basis, then each spray will apply 12 ounces per acre. The estimated cost of the material is 12 ounces/acre x $5.63/ounce = $67.56 per acre per spray. Two sprays to obtain season-long growth control will require a total of 24 ounces for an estimated $135.12 per acre. This will lead some growers to ask how thin Apogee can be stretched before it breaks.

My suggestion for 2001 is to treat the majority of the block exactly as described in the previous paragraph. The most expensive spray is the one that fails, and it is important to see what Apogee can do before experimenting with lower rates. That said, there are some legitimate ways to try to achieve savings.

The first opportunity for savings may come about by using the monitoring strategy. If the first Apogee application of 6 ounces per 100 gallons dilute controls growth for 6 weeks or more and the untreated check trees are slowing down at the time that a second spray is needed, then 3 ounces per 100 dilute may be all that is needed in that second spray to achieve control for the rest of the season. This would use only 18 ounces of Apogee for the season. The estimated cost of the Apogee would be $101.34 per acre, saving $33.78 per acre.

A similar idea would be to plan on making 3 sprays at 3 ounces per 100 gallons, dilute rate. In the example of a 200 gallon tree row volume block, this plan also aims to control growth with a total of 18 ounces of Apogee per acre, by monitoring growth to get the maximum duration out of each spray.

Another opportunity to get results and savings comes about when the need to control vigor in the trees is confined to the top of the canopy. Shutting off the bottom 2 nozzles will direct the Apogee to where it is needed, while reducing the spray output per acre. This will extend the amount of acreage covered by each tank of spray, and reduce the cost per acre.

(Jim Schupp, jrs53@cornell.edu, Horticultural Sciences, Highland)

Evaluating spur quality and bloom density is always a good idea, and especially so this year. Healthy spurs with numerous, large leaves have the highest potential for setting fruit and for supporting fruit during the early stages of growth. Since most of the early growth in developing fruits is due to cell division, this early growth also largely determines the fruit growth potential for the rest of the season.

Once development reaches the pink stage, growers can begin to evaluate return bloom and make some preliminary notations about bloom density this season. This spur and blossom information can then be combined with notes on pollination, initial fruit set, early fruit growth, seed number and other observations that you will find valuable for decision-making at thinning time.

Many orchards in N.Y. have produced large crops for two years in a row. This may have depleted nutrient reserves and such blocks may have lighter bloom and be predisposed to set a lighter crop in 2001. Other blocks carried big crops in 1999 and came back a little light in 2000. These trees will be predisposed to have heavier bloom and set in 2001, as will those blocks that had light crops last year due to blossom damage from a freeze last April.

Some growers thinned hail-damaged blocks very aggressively last year to remove as much of the damaged fruit as possible. This practice should result in heavier bloom and set in 2001. Strong thinning materials, such as ethephon and naphthalene-acetic acid (NAA) stimulate return bloom through direct hormonal action as well as by removal of competing crop. Even in blocks where these late thinning treatments weren't very effective for removing last year's crop the tendency of these materials to increase flower formation may be noticeable.

Some hail-damaged blocks received minimal care in 2000. Pesticides, herbicides and mowing were curtailed to cut expenses. In some cases the crop was not harvested or was harvested late for juice. Bloom will probably be lighter and weaker in such "low maintenance" blocks.

Many regard chemical thinning to be the most important single spray decision a grower makes in any given year. Little wonder then that this spray also causes a lot of worry. It is too early to make thinning decisions, but not too early to jot down some notes to include in your decision-making process on chemical thinning. Recording this information now can help you to remember all the relevant information about thinning decisions and will result in less stressful decision making when the time comes. Take the time to jot down your observations for each block in a small notebook that fits in your shirt pocket. While not as trendy as a palm pilot, the batteries don't run down and you can sharpen a pencil with a pocketknife.

What can be done to increase set, if bloom appears light and the flowers weak? Foliar sprays of urea tank-mixed with boron at pink, petal fall and first cover have been beneficial. See the new Nutrient Management section of Cornell Recommends for details on rates, timing, and compatibility. A new and less proven method for increasing set in apple is Apogee. The label recommends 10—12 ounces Apogee per 100 gallons, dilute basis, at 1—3 inches of shoot growth for increasing fruit set.

Scaffolds 2001 index