Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
There are four points that should be considered when applying Apogee to apples: timing, rate per acre, thinning relationships and compatibility.
Apply Apogee when vegetative shoot growth is less than three inches. This is about a 7-to 10-day window commencing at the king bloom petal fall stage. Most years all varieties can be treated at this time. The second application should be applied two weeks later and the third application two weeks after the second. Sometimes a fourth application is needed, but that is optional based on crop load and tree vigor. Excessive rainfall and light crops will promote vegetative growth; therefore an additional fourth application may be needed.
Rate per acre is usually calculated on a tree row volume basis and can be adjusted to two-thirds of the label full rate. The two-thirds rate is the starting rate growers should consider if they don’t have any experience using Apogee in the past. Past experience on your block will indicate if this rate is too high or too low per acre. This suggested two-thirds rate per acre is a season long rate per acre. For example, if your trees are at 75 percent tree row volume, then 24 ounces per acre is the seasonal rate (48 * .75 * 2/3). Best results occur when seasonal rate is split into three or four sprays. For example, 8 + 8 + 8oz per acre. When fire blight is a severe risk, the first application at king bloom petal fall timing should be increased, perhaps as much as 150 percent of a split rate. For example, increased from 8 ounces per acre to 12 ounces per acre. Subsequent sprays, the second and third sprays could be reduced, so the seasonal application would be 12 + 6 + 6 = 24 ounces per season.
Apogee tends to increase fruit set, therefore more aggressive thinning is needed. Increase your thinning by 10 or 15 percent. For example, if you were going to thin with 1 pt Sevin + 8 ppm NAA, then consider 1 pt Sevin + 10 ppm NAA where you are using Apogee.
Apogee is not compatible with calcium or boron in the tank. Also, we suggest that Apogee be applied after a thinner. If the two-week timing interval is also the ideal time to thin, make your thinning application first and then a couple days later follow with Apogee. Remember to include the label recommendations for AMS and surfactants.
In summary; Apogee is an excellent tool to help control vegetative growth and especially suppress fire blight spread among shoots and within shoots. Follow these tips to get the most out of Apogee.