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W.P. Cowgill Jr., M.H. Maletta, T. Manning, W.H. Tietjen, S.A. Johnston, and P.J. Nitzsche

Research trials, conducted from 1991 to 1998, evaluated early blight forecasting systems for use in fresh-market tomato (Lycopersicon esculentum) production in northern New Jersey. Initial trials focused on determining which of three forecast systems—NJ-FAST, CU-FAST, TOM-CAST—would optimize fungicide use. The TOM-CAST system generated fungicide application schedules that reduced foliar disease rating compared to the untreated check and, in 1 year, controlled diseases as well as a weekly schedule with 3 rather than 14 applications. TOM-CAST was easier to use than NJ-FAST or CU-FAST because it required fewer weather data inputs and simpler forecast calculations. Subsequent trials evaluated and defined thresholds for using TOM-CAST in northern New Jersey and evaluated the efficacy of several fungicides with TOM-CAST. Of the six TOM-CAST modifications evaluated, TOM-CAST beginning fungicide applications at 25 cumulative dew severity values (dew SV) and reapplying fungicide at 15 or 25 cumulative dew SV reduced disease rating as much as a weekly schedule in 1995 and 1996 and with fewer applications. After 5 years of trials, decision thresholds for using TOM-CAST in northern New Jersey were chosen and this new version of the forecast system designated NJ-TOM-CAST. It was verified in 1997 and 1998 and shown to generate fungicide application schedules that reduced foliar disease rating compared to the untreated check in both years and as much as the weekly schedule in one year. From 1995 through 1998, the conservative TOM-CAST schedules, TOM-CAST 25-15 or NJ-TOM-CAST, required on average 6 fungicide applications per year compared to weekly schedules that required on average 15 applications per year. In 1996, marketable yield was increased with TOM-CAST scheduled treatment compared to the untreated check and was the same as or greater than yield with weekly treatment. In the other 3 years, fungicide applications, whether applied on a calendar-based or TOM-CAST-based schedule, did not increase marketable yields compared to the untreated check. Fungicides shown to be effective when used with NJ-TOM-CAST schedules included both low cost and new chemistry materials. Copper fungicides, some of which are allowed in organic crop production, did not consistently control fungal diseases when applied on the NJ-TOM-CAST schedule. Applying fungicides on the NJ-TOM-CAST schedule instead of calendar-based schedules did not increase bacterial disease severity. Powdery mildew damage was more severe with NJ-TOM-CAST-scheduled applications than weekly applications in 1 year, affirming the importance of disease monitoring in the field when using NJ-TOM-CAST. By 2000, through a cooperative effort of Rutgers Cooperative Extension and SkyBit, Inc. (Boalsburg, Pa.), a commercial weather service, NJ-TOM-CAST was available to northern New Jersey tomato growers by subscription.

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M.H. Maletta, W.P. Cowgill Jr., W. Tietjen, P. Nitzsche, and S.A. Johnston

Since 1990, FAST - Pennsylvania State University, CUFAST - Cornell University. and TOM-CAST - Ridgetown College, Ontario, three systems for forecasting early blight, have been field tested at The Snyder Research and Extension Farm in northwestern New Jersey for their potential use in fresh market tomato production in that area of the state. In 1993, the number of fungicide applications for tomato early blight control required by the three forecast systems was less than the number required following a weekly schedule. FAST and CUFAST scheduled applications of chlorothalonil, 1.5 lb per acre, reduced disease severity, hut TOM-CAST scheduled applications did not reduce disease severiety compared to the untreated control. Culture did not affect disease control results hut did affect disease incidence and post-harvest losses. Total and marketable yields were not affected by fungicide application schedule. Potential cost savings of $270 or $465 per acre, resulting from reduced numbers of fungicide applications following CUFAST or FAST. were estimated. Chemical name used: tetrachloroisophtalonitrile (chlorothalonil).

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M.J. Willett, E.L. Proebsting, and R.E. Redman III

Flower buds of peach, apricot, and sweet cherry are killed by low temperatures during winter and spring. Frost protection measures used commonly in the spring are applied to freeze protection during the winter in the Yakima Valley of Washington. Critical temperatures change rapidly during winter. To succeed, winter freeze protection requires adequate inversions, equipment that operates at temperatures below -15C, and reliable estimates of critical temperatures for flower bud survival. Observations and experience have shown that inversions develop on most critical winter nights. Wind machines and orchard heaters will operate under severe low-temperamre conditions. Winter freeze protection has been practiced successfully on an increasing scale in the Yakima Valley for more than 20 years. Five packinghouses operate laboratories to measure critical temperatures. A computer model that estimates critical temperatures from daily or hourly air temperatures is being incorporated into these estimates.

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Nita A. Davidson, L. Theodore Wilson, Michael P. Hoffmann, and Frank G. Zalom

Temperatures recorded by weather stations and within the canopy of tomato (Lycopersicon esculentum Mill.) crops were compared in fields near Davis, Calif., during Summer 1983 (60 days) and 1987 (50 days). For both years, the average maximum and minimum temperatures, daily temperature ranges, degree days per day, and total accumulated degree days were compared. In 1983, the mean maximum temperature at the weather station did not differ significantly from that in the canopy, but the mean minimum temperature at the weather station was significantly lower than that in the canopy. In 1987, the mean maximum temperature at the weather station was significantly higher than that in the canopy, but mean minimum temperatures did not differ significantly. Temperature ranges were significantly narrower for the weather station toward the end of the 1983 season, and significantly wider for the weather station at midseason 1987. Comparisons of degree days per day showed significant differences between means at the weather station and in the canopy in 1983, and among those at the weather station and the two degree day calculation methods used for temperatures recorded in the canopy. Total accumulated degree days based on temperature records at the weather station were lower than those in the canopy in 1983 but higher in 1987. In 1987, the single sine degree day calculation method overestimated degree days compared to the 2-hr triangulation method. The phenology of the tomato crop as predicted by weather station temperatures indicated that tomato maturation was underestimated in 1983 and overestimated in 1987. The rate of development for hypothetical populations of Heliothis zea (Boddie) and Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) within the tomato crop was again underestimated in 1983 and overestimated in 1987, as based on temperature data of the weather station.

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Jenny L. Bolivar-Medina, Camilo Villouta, Beth Ann Workmaster, and Amaya Atucha

Crop forecasting is a highly desirable tool for fruit production. For cranberry, early and accurate yield prediction would benefit handlers and processors to plan for crop volumes and fruit prices; most importantly, it would allow growers to

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Jonathan M. Frantz, Bryon Hand, Lee Buckingham, and Somik Ghose

, pressing the “Calculate Heating Costs” button retrieves the 2-d forecast from a website ( National Oceanic and Atmospheric Administration, 2010 ) that is specific to that zip code. In a few seconds, the forecast appears in the top part of the window, broken

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Michele Renee Warmund, Patrick Guinan, and Gina Fernandez

divided into forecast zones, often by county. In states that have fairly small counties and uniform topography, there is only one forecast zone per county. In states that have large county boundaries, significant elevation change, or coastal influence

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Arthur Villordon, Christopher Clark, Tara Smith, Don Ferrin, and Don LaBonte

agrometeorological conditions 5 DAT appears related to transplant establishment and its direct relationship to the determination of potential yield in sweetpotatoes. The availability of 10-d weather forecasts and other agrometeorological-related services allows

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E. Vanessa Campoverde, Georgina Sanahuja, and Aaron J. Palmateer

preventative pesticide applications when weather forecast is for heavy rains. Preventative measures to avoid the establishment and dispersal of these pathogens are crucial for effective disease management. Units Literature cited Agrios, G.N. 2005 Plant

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Katrine Heinsvig Kjaer and Carl-Otto Ottosen

photosynthesis and forecasted solar irradiance; thus, the light breaks were not identical between nights. The overall result was a light pattern that was very irregular. Plants are adapted to sense daylength to schedule developmental events to coincide with