In the coming weeks you will likely see nuts dropping from the trees. While insects can cause this as well, mass nut shedding with no visible insect injury will likely be water split. Details from previous post below:<\/p>\n Water split is a major problem exhibited by thin-shelled pecan varieties\u00a0(e.g., Schley, Caddo, Oconee, Sumner, Wichita, Frotscher, and Farley) and, to a lesser degree, by certain relatively thick-shelled cultivars (e.g., \u2018Cape Fear\u2019 and \u2018Elliott\u2019).\u00a0 The problem occurs when water pressure builds up rapidly inside the nut, causing the shell, seed coat, and sometimes the shuck to split about the time of the initiation of kernel filling and shell hardening, resulting in abortion and drop of damaged fruit about 7 days after splitting.<\/em><\/p>\n Water split is highly erratic, with incidence and severity varying depending on cultivar, location, and year. Crop loss can be severe in certain years and nearly absent in others.\u00a0\u00a0It occurs during the \u201clate water stage\u201d; a time when turgor pressure inside the nut is high and the shell is beginning to harden.\u00a0 This typically occurs during mid-August for susceptible cultivars growing in the southeastern U.S.<\/em><\/p>\n Water split is\u00a0associated with rainfall occurring at the initiation of shell hardening. There are usually 2 episodes to water split. The major episode\u00a0is\u00a0usually\u00a0triggered by rainfall (or potentially irrigation) and a relatively minor event triggered by \u201chigh humidity\/low light\u201d.\u00a0 Irrigation schedule, shading, and crop load also factor in.<\/em><\/p>\n Often, the split is inside the nut and you will simply see green nuts on the ground, which will stain a few days later. Other times when the incident is particularly violent you will see an actual longitudinal split in the shuck itself.<\/em><\/p>\n By the time you see water split, there\u2019s little that can be done. Crop loss to\u00a0water split\u00a0is minimized, but not totally prevented, by managing soil moisture to minimize the severity and duration of water stress during the last two weeks of fruit sizing, and by crop-load thinning.\u00a0 Certain varieties will always have a potential for it under the right conditions. It seems to be worse when there\u2019s been a dry spell and you suddenly get a heavy rainfall or crank up the irrigation all of a sudden. This does not mean that you do not need to irrigate. It means you don’t need to go from dry to wet extremes quickly. Instead, maintain good, consistent soil moisture before increasing irrigation for kernel filling.<\/strong> Water split also appears worse when the trees\u00a0are bearing a heavy crop load. This is another reason to maintain good soil moisture and minimize water stress through the entire season. Foliar sprays of B and Ni in the spring have also led to reductions in water split.<\/em><\/p>\n Time to Crank Up the Water<\/strong><\/p>\n When shell hardening arrives and nut sizing is done in mid-August, we shift to the kernel filling stage. This is the period of peak water demand for pecan (This occurred for Pawnee a week or two ago). Growers need to apply the maximum rate of irrigation possible up to 4000 gallons per acre per day from mid August to mid September on bearing trees. Trees with a heavy crop load will use a lot more water than most people realize to fill the kernels during this period. Therefore, remain on your full daily schedule (12-15 hrs\/day) unless you get a rain event of 2″ or more. If you do get a 2″ rain, turn the water off for 3 days and then turn it back on again. I cannot emphasize the value of adequate water in this situation enough. If you want to avoid poor quality in a year where quality will be extremely important to the price you receive for your crop do not cut corners on irrigation at this time.<\/em><\/strong><\/p>\n![\"\"](\"https:\/\/site.extension.uga.edu\/pecan\/files\/2014\/08\/Caddo-Water-Split-2.jpg\")
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