Tank-Mixing Boron and MaxCel
Influences 'Gala' Apple Size and Quality
Because large ‘Gala' apples are in short supply and consequently generate high premiums, there is considerable effort made to enhance ‘Gala' fruit size. MaxCel (Valent BioSciences, Libertyville, IL) can be applied for the express purpose of enhancing fruit size. The MaxCel is reported to increase cell division during early fruitlet development, which ultimately will produce large fruit. The belief than tank-mixing boron (B) can enhance the activity of selected plant growth regulators has been around in the industry for 10 years or more. Substantially increasing ‘Gala' fruit size may predispose fruit to quality problems, such as firmness loss and stem- end splitting.
Treatments in 2004:
4 sprays at 3 to 10 day intervals starting at petal-fall -
• 10 ppm MaxCel + 0, 447, or 894 ppm B as boric acid
• 30 ppm MaxCel + 0, 447, or 894 ppm B as boric acid
• 50 ppm MaxCel + 0, 447, or 894 ppm B as boric acid
• 50 ppm MaxCel + 2378 ppm calcium as MiraCal
Fruit were harvested on 16 August 2004 and analyzed individually for mass and splitting. Fruit firmness was measured on all apples weighing between 180 and 200 grams.
• the MaxCel sprays alone increased fruit size without reducing firmness or increasing splitting;
• adding low to moderate levels of boric acid slightly enhanced fruit size at 10 and 30 ppm MaxCel;
• adding a high level of boric acid reduced fruit size, reduced firmness, and increased splitting.
• tank-mixing MiraCal had no effect on fruit responses.
Frank J. Peryea, Ph.D., and Kaz Lorentz
December 22, 2004