by Terence Bradshaw

As we see harvest coming right around the corner, the time to apply ReTain for drop control is upon us. Dr. Duane Greene from UMASS presented at the 2015 UVM Apple Program / Vermont Tree Fruit Growers Association meeting on the use of ReTain and NAA for drop control, slides from his talk can be found at: http://www.uvm.edu/~fruit/treefruit/tf_meetings/PGRsVTFGA15.pdf

In summary:

• The ReTain label limits application to a maximum of 333g active ingredient per acre, but lower rates and multiple applications may be made.
• Earlier application timing results in greater delay in ripening, later timings improve drop control.
• Multiple applications at reduced rates may be more successful than a single application.
• NAA (Fruitone) may also improve drop control but when used alone may advance ripening and reduce storage life.
• NAA when applied with a half-rate or ReTain will improve drop control with less delay in ripening and reduction in red color than ReTain applied alone.

Growers should consider beginning ReTain applications on September-ripening cultivars (McIntosh, Gala, Cortland, Honeycrisp) in the next week if they have not already. Full rates may be made at this time, or half rates so long as a follow up spray will be applied. Inclusion of 10 ppm NAA may be warranted on cultivars and blocks where poor color development has been an issue where ReTain was used alone. A second application of ReTain may be made in another two weeks. This will allow for harvest of McIntosh and Gala beginning the week of September 7. For Honeycrisp and Gala, lower rates may be warranted. All ReTain sprays should include a non-ionic surfactant to increase uptake of the active ingredient. Plant growth regulator applications should be made alone without tank-mix components that may reduce material effectiveness.

by Terence Bradshaw

As the calendar flips to August, it’s time to wrap up field activities in preparation for harvest in Vermont orchards.

Foliar nutrient analysis – It is the time in the growing season to collect leaf samples for analysis. Samples are usually collected between July 15 – Aug. 15. The UVM Agriculture and Environmental Testing Lab can provide analysis, but at this time their output does not generate fertility recommendations. The following are potential options of labs for analysis. It is recommended that you contact the lab for instructions and costs before samples are sent. Plus, it is important to confirm that they will send recommendations along with the analysis.

(1) University of Maine Analytical Lab: http://anlab.umesci.maine.edu/
(2) University of Massachusetts Soil and Tissue Testing Lab: http://www.umass.edu/plsoils/soiltest/
(3) Cornell Nutrient Analysis Lab: http://cnal.cals.cornell.edu/

Wrapping up spraying – Primary insects of concern are apple maggot and codling moth. Both should be managed in high-pressure orchards. AM can often be managed with a single insecticide application based on monitoring with red sticky traps. The threshold is one fly per unbaited trap, or five flies per trap if apple volatile baits are used. Codling moth are entering their second flight in many orchards, so management is advised if this pest is a problem for you. Insecticide options are listed in the 2014 New England Tree Fruit Management Guide. Dr. Arthur Agnello discusses these summer insect pests in more detail in the July 7, 2014 issue of Scaffolds .

Summer diseases – It is important to maintain fungicide coverage to protect against sooty blotch, fly speck, and summer fruit rots. Materials should be applied after every 200 accumulated hours of leaf wetness or 2 inches of rainfall, whichever occurs first. Except on later-harvested cultivars, a fungicide application made by mid-month should provide good control through harvest. For retail orchards, fungicide sprays are likely wrapped up by now.

Remember to watch pre-harvest intervals on all products at this time of year.