Issue link: http://read.dmtmag.com/i/61297
Soils & Nutrients Selecting herbicides FOR TREE FRUIT F Herbicide rotation programs avoid weed resistance and improve weed control. by Richard Lehnert ruit growers have a choice among several resid- ual herbicides and postemergence herbicides that are registered for application in tree crops, and they should use several each year to manage the vegetation in the tree strip. Reliance on too few herbicides can lead to weed resist- ance to herbicides, proliferation of weed species that are not suppressed by the chosen herbicides, or to a build-up of herbicides in the soil that may result in tree injury, says Dr. Bernard Zandstra, the horticultural weed control specialist at Michigan State University. Zandstra reported that several new herbicides have been labeled for fruit trees in recent years, and others are in the process of registration. With several active herbi- cides available for residual weed control, he advises grow- ers to know the modes of action of the various herbicides, and then use herbicides with at least two different modes THE of action when making applications of preemergence materials in fall and spring. Then rotate herbicides with different modes of action every year. Along with the resid- ual herbicides, he recommends using foliar-active herbicides to kill emerged weeds. Zandstra spoke to apple and cherry growers at the Northwest Michigan Orchard and Vineyard show in January 2012. He outlined some "model" herbicide programs that fruit growers might use over several years. Weed control in apples In apple orchards established for three years or more, Zandstra suggested this three-year program for apples (rates are pounds of product per acre of land treated, not per acre of orchard): Starting in the spring of year one, apply 1 pound of Sinbar (terbacil)or 3 pounds of Karmex (diuron). Then follow-up in June with a quart of glyphosate and 2 ounces of Venue (pyraflufen-ethyl). In the fall, use 5 ounces of Alion (indaziflam) and 1 quart of glyphosate. In the spring of the second year, apply 4 ounces of Matrix (rimsulfuron), 3 pounds of Karmex, and glyphosate. In June, apply 1 ounce of Treevix (saflufenacil) and 1 ounce of Venue. In the fall, apply 4 pounds of Solicam (norflurazon) and 1.4 gallons of Casoron CS (dichlobenil), and 1 quart of glyphosate. In year three, start with 4 pounds of Princep (simazine) plus 4 quarts of Surflan (oryzalin) or Prowl H2O (pendimethalin) in the spring. In June, apply 3 pints of Rely 280 (glufosinate-ammonium) and 1 ounce of Venue. In the fall of year 3, apply 8 to 12 ounces of Chateau (flumioxazin), plus glyphosate. Zandstra recommends using glyphosate once or twice each year, in spring and in fall, to kill emerged weeds. If no SPIDER POLE Cherry Thinner NNO MORE LS! 32 APRIL 15, 2012 GOOD FRUIT GROWER www.goodfruit.com NEW Call Foothills EW Call Today!