Issue link: https://read.dmtmag.com/i/506700
www.goodfruit.com GOOD FRUIT GROWER MAY 15, 2015 25 and Skeena in two orchards and found the best results of enhancing calcium tissue content came from six weekly applications, beginning at pit-hardening and up to one week before harvest. Nine weekly applications had no advantage over the six, and two applications at pit hard- ening and one week before harvest was not enough to increase calcium content in fruit tissue. Rates of about 0.1 percent calcium worked best, Wang reported. Leaf burn- ing was observed when calcium rates were higher than 0.15 percent calcium based on calcium chloride and calcium citrate. "Frequent applications were found to be more important than exact spray tim- ing," he said, and added that leaves were more susceptible to burning during the early development stage. Wang tested several different calcium formulations (calcium chloride, calcium nitrate, calcium citrate, "Cal-8," and "Chelate Ca"). He found that chelated calcium at 0.05 percent calcium and Cal-8 at 0.2 percent calcium (their label rates) were more effective in improving fruit firmness than calcium chloride (at 0.1 to 0.15 percent calcium), calcium nitrate (at 0.1 to 0.15 percent calcium), and calcium citrate (at 0.07 percent calcium of its label rate). If sprays were made six times on a weekly basis, both calcium chloride and calcium citrate decreased fruit size— although size was not a problem with any of the other calcium formulations. By enhancing fruit tissue calcium concentrations through the preharvest sprays, Wang found improved shipping quality in terms of reducing pitting, decay, pedicel browning, skin darkening, and losses of firmness and acidity after three weeks of cold storage. Wang also investigated adding cal- cium chloride to hydro-cooled water as a way to increase calcium content. Hydro-cooling fruit shortly after harvest is commonly done to eliminate field heat. Adding calcium chloride to the hydro-cooling water at 0.2 to 2.0 percent calcium and running fruit through the hydro-cooled water for five minutes under research conditions was enough to significantly increase the tissue calcium content without fruit uptake of chlorine. Wang's hydro-cooling addition increased calcium content in Lapins, Sweetheart, Skeena, and Bing by 30 to 190 percent. The increases were dependent on the calcium rate and cultivar. Benefits of adding calcium chloride to the hydro-cooling included: —Increased fruit firmness —Reduced pitting susceptibility —Reduced splitting potential —Reduced respiration rate and maintained acid and flavor —Reduced decays He also found that low rates of calcium chloride (0.2 to 0.5 percent), helped keep stems green in fruit held in storage for three weeks. However, stem quality was damaged if higher rates of 1 to 2 percent calcium were used. Wang also conducted the hydro- cooling trial under commercial settings by adding 2,040 parts per million of calcium (Opti-Cal) to the hydro-cooling water at a commercial cherry packing house. Six lots of Bing and Tieton cherries were treated with calcium in the hydro-cooling water. The calcium increased firmness of most of the fruit, though not of fruit that was very firm to start with (firmer than 350 grams per millimeter). But it did decrease pit- ting in all the lots. Wang will continue his calcium research this year, expanding it to more varieties and gathering more data, including effects on return bloom, yield, size, and storage quality. • "Fruit that had higher calcium concentrations were ϔ least amount of pitting." —Yan Wang Contact your local crop advisor or dealer, or visit cheminova-us.com FUNGICIDE Specialty Crops Give your crop the advantage This season make TOPGUARD® Fungicide Specialty Crops your ĮƌƐƚĂƉƉůŝĐĂƟŽŶƚŽƉƌŽǀŝĚĞĞĂƌůLJĐŽŶƚƌŽůŽĨƉŽǁĚĞƌLJŵŝůĚĞǁŝŶLJŽƵƌ ƉŽŵĞĂŶĚƐƚŽŶĞĨƌƵŝƚĐƌŽƉƐ͘LJƌĞĚƵĐŝŶŐŝŶŽĐƵůƵŵůĞǀĞůƐ͕ ŝƚǁŝůůůŽǁĞƌƚŚĞŝŵƉĂĐƚŽĨŽǀĞƌͲǁŝŶƚĞƌŝŶŐĨƵŶŐŝĂŶĚŐŝǀĞLJŽƵ ĂŶĂĚǀĂŶƚĂŐĞƚŽƐƚĂƌƚƚŚĞƐĞĂƐŽŶ͘ ŌĞƌƚŚĞĮƌƐƚĂƉƉůŝĐĂƟŽŶ͕ŝŶĐŽƌƉŽƌĂƚĞTOPGUARD Specialty Crops ĂƐĂǀŝƚĂůĐŽŵƉŽŶĞŶƚŽĨLJŽƵƌĨƵŶŐŝĐŝĚĞƉƌŽŐƌĂŵƚŽŵĂdžŝŵŝnjĞ LJŽƵƌĨƌƵŝƚƋƵĂůŝƚLJĂŶĚƚƌĞĞŚĞĂůƚŚ͘ ůǁĂLJƐƌĞĂĚĂŶĚĨŽůůŽǁůĂďĞůĚŝƌĞĐƟŽŶƐ͘dKW'hZ&ƵŶŐŝĐŝĚĞ^ƉĞĐŝĂůƚLJƌŽƉƐŝƐŶŽƚƌĞŐŝƐƚĞƌĞĚŝŶĂůŝĨŽƌŶŝĂ͘ ΞϮϬϭϱŚĞŵŝŶŽǀĂ͕/ŶĐ͘dKW'hZŝƐĂƌĞŐŝƐƚĞƌĞĚƚƌĂĚĞŵĂƌŬŽĨŚĞŵŝŶŽǀĂ͕/ŶĐ͘