Issue link: http://read.dmtmag.com/i/61297
Bernard Zandstra's herbicide testing program shows the strengths and weaknesses of individual herbicides. weeds are present, the glyphosate might not be needed. Zandstra also reminded the growers that young trees are susceptible to glyphosate injury, and their stems should not be sprayed. He said that the rotation of herbicides and modes of action is important, not the particular chemical order. You can start a herbicide rotation in spring or fall. Weed control in cherries For weed control in cherries, Zandstra recommends ounces of Matrix. Then in June, use 2 ounces of Aim (car- fentrazone) plus 2 ounces of Venue. That fall, apply 5 ounces of Alion and 1 quart of glyphosate. In year two, start in the spring with 2 quarts of Goal- use of glyphosate only once each year in the fall. Here's his "model" three-year program for cherries: In the spring, apply 4 quarts of Prowl H2O and 4 Tender (oxyfluorfen) and 2 quarts of Surflan. In June, use a quart of Gramoxone (paraquat) and 2 ounces of Venue, but remember that Gramoxone has a 28-day preharvest interval. In the fall, use 6 to 12 ounces of Chateau and a quart of glyphosate. In the third year, start in the spring with 4 quarts of Prowl H2O and 4 ounces of Matrix. In June, use 2 quarts of Gramoxone and 2 ounces of Venue. That fall, apply 5 ounces of Alion and 1 quart of glyphosate. Zandstra indicated that growers might want to try Alion for long residual control in apples and cherries. Alion, from Bayer CropScience, is a new herbicide regis- tered for pome and stone fruits, and it will be registered for additional fruit crops in the future. Alion has long residual activity, and is active against weeds that have developed resistance to Karmex, Princep (simazine), glyphosate, and other widely used herbicides, he said. Sandea (halosulfuron-methyl) is now labeled for pre- emergence and postemergence control of yellow nutsedge in apples. It also controls pigweeds and most composites. The Sandea label will be expanded to include other fruit crops in the coming years. Treevix is a new herbicide from BASF that is especially effective against horseweed (marestail). It currently is labeled for apples and pears. Zandstra reminded the growers that Kerb (pronamide) is an old herbicide that is very effective against quack- grass, especially when applied in the fall. He also said that Select Max (clethodim) is the most effective graminicide for postemergence control of annual bluegrass, which is often a problem in fruit orchards in the spring. Stinger (clopyralid) may be used postemergence in cherries for control of horseweed, common ground sel, dandelion, Canada thistle, goldenrod, and legumes. There are several other herbicides being developed for tree fruit, including Mission (flazasulfuron) from ISK Biosciences, Trellis (isoxaben) from Dow AgroSciences, Spartan (sulfentrazone) from FMC, and Pindar (penoxsu- lam plus oxyfluorfen) from Dow AgroSciences. Zandstra encouraged fruit growers to watch for news that these herbicides are labeled for their crops. • www.goodfruit.com GOOD FRUIT GROWER APRIL 15, 2012 33 photo by RIChARD LEhNERt