Scaffolds 01 index

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

Water from sources with high concentrations of calcium carbonates, known as hard water, will inactivate Apogee. Most surface water sources, such as ponds, have soft water, while many wells have hard water. Water hardness can be tested, either by a water quality lab, or with test strips available at pool and spa suppliers.

Use of a water conditioner is advisable if the calcium concentration is 200 ppm or more. Spray grade ammonium sulfate (AMS) is effective, as are a number of proprietary water conditioners, available from chemical distributors.

The best way to determine how much conditioner is needed is to test a full spray tank of plain water before adding any spray material. If the hardness is 200 ppm or more, then start by adding 1 pound of AMS for every pound of Apogee you intend to put in the tank. Follow the label instructions if you are using a proprietary product. Retest after the conditioner is thoroughly mixed, adding more product as necessary to bring the level of hardness down below 200 ppm. Once the amount of conditioning for a water source has been established, any additional tanks of Apogee using that source can be mixed with the same amount of conditioner.

Use of a surfactant is recommended. A number of different non-ionic and organosilicone spray adjuvants have been used in Apogee research plots with good success.

Apogee is compatible with most commonly used pesticides. Do not apply Apogee with calcium sprays, as the calcium will inactivate Apogee.

One of the "gray areas" in our knowledge on Apogee is whether there is a problem with applying products containing gibberellic acid (GA), such as ProVide and Promalin or their generic equivalents, and Apogee to the same trees. A 2000 study of Apogee +/- ProVide, conducted on Golden Delicious in the Hudson Valley, suggests that there is no problem; however, until we can confirm these results with additional research, it is best to avoid using GA products on Apogee-treated trees.

Another "gray area" is the potential effect of Apogee on fruit set. Some studies have shown that 12—16 ounces Apogee per 100 gallons increases fruit set. Other studies have documented no effect of Apogee on fruit set. Our 2000 study on Golden Delicious was one of the latter. While the results of research are as yet inconclusive, the Apogee label contains a section recommending its use to increase fruit set on young trees.

Apogee has no direct effect on fruit size or quality; however, if Apogee increases fruit set and the grower does not respond by thinning off excess fruit, the increased crop load will result in smaller fruit. Use lower rates of Apogee where the level of vigor permits, and be prepared to adjust thinning strategies to remove more fruit if initial set is too high. If the amount of additional thinning required is not great, a 20—30% increase in chemical thinner concentration may be adequate to get the desired result.

Increasing the concentration of thinner may not be an adequate solution in situations where fruit set is excessive. The amount of additional thinning achieved by increasing the thinner concentration often doesn't result in a proportionate reduction in fruit set. Besides the diminishing thinning activity, high concentrations of chemical thinners sometimes have undesirable side effects, most notably foliar damage and reduced fruit size. An alternative solution is to add another thinner or to apply the usual dose of thinner with spray oil to increase its activity.

Scaffolds 2001 index