Issue link: http://read.dmtmag.com/i/291333
www.goodfruit.com GOOD FRUIT GROWER APRIL 15, 2014 19 First, the new herbicides will come in complicated "packages" so growers won't be able to choose to use 2,4-D alone to attack glyphosate-resistant weeds; they will now attack weeds with a cocktail of herbicides in premixes. Some of the companies selling the new prod- ucts may have them labeled in such a way that it would be an off-label, technically illegal use to spray them with any other herbicide but the premix. Second, she questions the merit of adding more her- bicide-resistance genes when Roundup has already demonstrated that weeds can become resistant to even the most lethal herbicide. A decade ago, it was considered highly unlikely that any weed would ever become resistant to Roundup. Now there is a growing list. Herbicide damage Growth regulator herbicides, espe- cially 2,4-D and dicamba, can cause severe leaf distortion and stunting in grapevines, according to Bruce Bordelon, the grape specialist at Purdue University. Damage is most severe when exposure occurs early in the season (April-May) during the early stages of shoot growth prior to grape flowering, he said. Grapes injured at this time can have severely dis- torted shoots and leaves, aborted or failed flowers, poor fruit set, and low yield. Leaves and shoots that develop a few weeks after 2,4-D exposure may be nor- mal. After dicamba exposure, vine growth usually fails to return to normal through- out the growing season. Late-season exposure to 2,4-D or dicamba may distort young leaves, but probably does not cause economic loss, Bordelon said. Grapes repeatedly exposed to these compounds become less productive, ripen later, and may eventually die from other causes due to their weakened condition. In Indiana, 2,4-D is primarily a burn- down herbicide used in no-till crop pro- duction. It's most frequently applied in April and May, which coincides exactly with the most sensitive grape growth period, Bordelon said. Dicamba is pri- marily applied postemergence to corn when plants are four inches or taller. With the new herbicide-resistant crops, use patterns of the herbicides will change. Ultimately, the resistant weeds that arise in corn and soybean fields will have to be fought in orchards, vineyards, and specialty crops fields as well, where genetic crop modification is not a tool. Glyphosate, which is widely used in tree fruits, will become less effective as resis- tant weeds move in, warns Dr. David Mortensen, weed ecologist with Pennsyl- vania State University. "During the period since the intro- duction of glyphosate-resistant crops, the number of weedy plant species that have evolved resistance to glyphosate has increased dramatically," he said. This list includes many of the most problematic weed species, such as common ragweed, horseweed, Johnson grass, and several of the most common pigweeds. According to the Penn State research team, despite company-sponsored research that indi- cated resistance would not occur, 21 different weed species have evolved resis- tance to glyphosate, 75 percent of which have been documented since 2005. • Effects of Using Nutri-Cal with Nutri-K on Cherries Effects of Using Nutri-Cal with Nutri-K on Cherries 366.28 g 369.50 g GRAMS FORCE TO SQUEEZE SKIN 1mm 364 365 366 367 368 369 370 FIRMNESS EVALUATION OF BING CHERRIES COMBINED MAHOGANY & DARK MAHOGANY % PREMIUM COLORS OF BING CHERRIES 89.25 95.75 75 80 85 90 95 100 Ron Britt & Associates, Yakima, WA 2012 Application Rate of 2 Quarts Nutri-Cal & 1 Quart Nutri-K Applied 6 times beginning at Petal Fall 2011 Application Dates: May 23, May 27, June 3, June 11, June 19, June 24 C.S.I. CHEMICAL CORP. 800-247-2480 • www.nutri-cal.com 10980 Hubbell Ave., Bondurant, Iowa 50035 PACIFIC NORTHWEST Walt Grigg: 509-952-7558 C.S.I. CHEMICAL CORP. 800-247-2480 • www.nutri-cal.com 10980 Hubbell Ave., Bondurant, Iowa 50035 PACIFIC NORTHWEST Walt Grigg: 509-952-7558 ® Make Sure You Always Ask For ® Make Sure You Always Ask For ® Make Sure You Always Ask For 17.00% 21.25% BRIX QUALITY OF BING CHERRIES 0 5 10 15 20 25 20 56.7 80 44.2 PREMIUM MEDIUM % MARKETABLE GRADES OF BING CHERRIES 0 10 20 30 40 50 60 70 80 Nutri-Cal 36% Increase in Premium Grade 8.5-9! DRIFTWATCH grows I n 2009, Purdue University created a system called DriftWatch so that specialty crop growers and field crops growers could better live in harmony. Specialty crops growers could input their crops and field locations on a Web site, and pesticide applicators could know where they were and avoid spraying in ways that might allow herbicides to drift in their direction. DriftWatch caught on quickly, as beekeepers and organic grow- ers also began mapping their locations on DriftWatch, hoping to keep all kinds of pesticides away from them. A new wave of crops that are resistant to 2,4-D and dicamba is of even greater concern. These older herbicides are less envi- ronmentally friendly than glyphosate, and vapor drift is much more frequent. Besides threatening injury to other crops, they can potentially affect natural landscape vegetation as well. Anyone wanting to participate, or just see what DriftWatch is about , can go to the registry Web site www.driftwatch.org or to the new company Web site at www.fieldwatch.com. —R. Lehnert