Issue link: https://read.dmtmag.com/i/481870
26 APRIL 1, 2015 GOOD FRUIT GROWER www.goodfruit.com Vineyards may need both postharvest and early spring irrigations to ensure adequate soil moisture at bud break. by Melissa Hansen E ven a two-week delay in filling up the soil profile in early spring when vines begin to break bud can reduce cluster counts and impact yields, according to Washington State University scientists. In recent years, WSU researchers have shown the importance of adequate soil moisture during bud break and the connection between bleeding or sap flow and bud break. Dr. Markus Keller, WSU horticulturist who specializes in grapevine physiology, and his colleague Dr. Bhaskar Bondada used potted Merlot vines to show the link between soil moisture and delayed bud break, reduced shoot growth, and reduced fruit set. (See "Irrigate early if winter is dry," Good Fruit Grower, February 15, 2013.) After the dry winter of 2005—when the Pacific Northwest received less than half of normal precipita- tion—many Washington vineyards had stunted shoot When soil moisture is CRITICAL Grape Irrigation Soil moisture can be depleted by spring A lthough applying a timely postharvest irrigation to fill up the soil profile before winter can go a long ways in helping ensure there is adequate mois- ture the following spring, not all growers are doing so, says Dr. Hemant Gohil. "There are many reasons why vineyard soil mois- ture is not adequate in spring," said Gohil, grape and tree fruit extension educator at Rutgers. Some growers forget to irrigate after harvest is done. Others may still be picking when irrigation districts shut down for the season and fear that irrigating while fruit is still hang- ing will affect fruit quality. "Moderately watering fruit before harvest has not been found to dilute fruit qual- ities," said Gohil, former technology transfer specialist with Washington State University. Filling up the soil profile at the end of the growing season can be particularly important for growers who practice regulated deficit irrigation strategies in red wine grapes because they likely have soil moisture levels that are below field capacity at the end of the season and need recharging. Gohil says that for those growers who implement severe deficit irrigation, it's even more critical that the vineyard is fully irrigated before winter. He's also heard some growers express fear that irrigating early in spring with cold water will delay Pest-Effective: • Season-long mating disruption • More starting active ingredient • 20% more pheromone released during the growing season Cost-Effective: • Season-long control with one application • Hand-application costs cut in half; no labor-intensive twist-ons • Minimal regulation • No harm to beneficial insects • No girdling losses Consistent, Season-Long Codling Moth Control NoMate ® CM Spiral is superior by design and performance for codling moth mating disruption in apple and pear orchards. No competing product goes on more easily, works harder, or gets better results. NoMate® CM Spiral is designed, manufactured, and supported in the United States by Scentry Biologicals, Inc., maker of the first pheromone-based product approved by the U.S. EPA. 610 Central Avenue Billings, MT 59102 (406) 248-5856 1-800-735-5323 www.scentry.com Slip-on NoMate® CM spirals consistently release volatilizing solid-matrix pheromone through flexible PVC dispensers. Female moth scent plumes are overwhelmed, thwarting male moth mating efforts. For more information, call 1-800-735-5323 or visit www.scentry.com.