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  • Author or Editor: W. Tietjen x
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Abstract

Freshly harvested, eastern-grown ‘Golden Delicious’ apples (Malus domestica Borkh.), were treated with 10%, 15%, and 20% CO2 for 13 days at 0°C prior to controlled-atmosphere (CA) storage. CO2-treated fruit was significantly firmer than the untreated fruit. Soluble solids and titratable acidity were not affected by the high CO2 prestorage treatment. During the 20% CO2 prestorage treatment, fruit from 1 orchard developed severe CO2 injury. Panelists rated fruit from the 10% and 15% CO2 treatments significantly better for flavor and texture than the untreated CA control and 20% CO2-treated fruit.

Open Access

Abstract

Clear polystyrene, foam polystyrene, and paper-pulp pint baskets caused significantly less cutting and bruising of strawberries than the widely-used plastic mesh basket (7.7, 8.1, and 6.4 vs. 18.2%, respectively). The excellent visibility afforded by the polystyrene baskets, and the relatively small storage space needed for the empty baskets, are potential ancillary assets of the clear polystyrene containers.

Open Access

Abstract

In 8 tests, sweetpotatoes [Ipomoea batatas (L.) Lam.] treated with 2,6-dichloro-4-nitroaniline (DCNA) and packaged had less waste after a week in a retail store than either treated or untreated sweetpotatoes retailed in bulk. Very good control of rhizopus soft rot in sweetpotatoes on sleeve-wrapped and completely overwrapped trays was obtained by DCNA. The combination of DCNA and the complete overwrap effectively reduced retail losses from soft rot and desiccation.

Open Access

Weather information has many applications in crop production practices, including disease forecasting. A variety of weather instruments are available for on-farm use, but associated costs and need for regular calibration and maintenance can limit actual use, especially by smaller growers. Subscription to an electronic meteorological service may be a viable alternative to on-site weather stations. In 1997 and 1998, hourly temperature, relative humidity and leaf wetness were monitored at six sites in a 400-m2 area of New Jersey with Field Monitor™ data loggers (Sensor Instruments, Inc.) and by subscription to SkyBit, Inc., an electronic meteorological service. There was close correspondence in temperature data from the two sources at all sites, the average seasonal difference ranging from 0 to 2 °F. Relative humidity data was variable between the two sources, the greatest variation occurring at low and high humidity, the ranges at which relative humidity sensors had been shown to be least accurate. Leaf wetness estimates from the two sources agreed at least two-thirds of the time. Data differences related to source were attributed to both systematic and random error. The usefulness of electronic weather data in crop production depends on how sensitive the particular weather-dependent applications (e.g., predictive disease and insect models) are to variation in the input data. The TOM-CAST early blight forecaster for tomatoes was not particularly sensitive to differences between SkyBit and Field Monitor leaf wetness estimates.

Free access

Five variations of TOM-CAST and two sources of weather data were used to schedule tomato early blight control for research trials at the Snyder Research and Extension Farm, Pittstown, N.J. TOM-CAST scheduled fungicide applications were initiated at 15, 25, or 35 disease severity values (DSV) and resprayed at 15 or 25 DSV. Weather data for generating the DSVs was obtained on-site with a Sensor Instruments Field Monitor™ or through subscription to the electronic meteorological service SkyBit, Inc. Bravo 720, 3 pints/acre, was used for disease control. Foliar disease, yields, and postharvest decays were evaluated. Daily DSVs, cumulative DSVs, and forecast spray schedule varied with weather data source. Because SkyBit data generated more DSVs during the season than Field Monitor data, the SkyBit-based forecasts called for one or two more sprays than the Field Monitor-based forecasts. However, the number of sprays actually applied was the same, one more or one less for each combination of initiation and respray thresholds. All treatment schedules reduced disease compared to the untreated control. Variation in initiation threshold did not affect disease control. All TOM-CAST schedules respraying at 15 to 20 DSV were as effective as the weekly schedule. All fungicide treatments increased total yields and reduced postharvest decays compared to the untreated control. Most treatments also increased marketable yields. The most efficient, effective Field Monitor-generated TOM-CAST schedule required nine sprays compared to 13 weekly sprays. The comparable SkyBit-generated schedule called for 10 applications. Chemical name used: tetrachloroisophtalonitrile (chlorothalonil).

Free access

Fourteen different fungicide schedules for early blight control, including eight variations of TOM-CAST, were evaluated at the Snyder Research and Extension Farm, Pittstown, N.J. Weather data was collected with Sensor Instruments Field Monitors. All calendar-based schedules—weekly, biweekly, grower simulation—reduced foliar disease compared to the untreated control. All forecast generated schedules—TOM-CAST variations, FAST and CUFAST—reduced foliar disease compared to the untreated control. Several of the forecast schedules resulted in disease ratings not significantly different from those following calendar based schedules or from each other. The fourteen different schedules required as many as sixteen to as few as four fungicide applications. Disease control schedule did not affect total yield, marketable yield and postharvest losses. Disease control with a TOM-CAST generated schedule based on weather data from an electronic meteorological service was not different from disease control obtained with a TOM-CAST schedule based on ground station weather data. Potential cost savings of as much as $295 per acre resulting from reduced fungicide schedules were estimated. Chemical name used: tetrachloroisophtalonitrile (chlorothalonil).

Free access

Fruit cracking in tomatoes is a serious problem, particularly when trellis culture is used. Past studies indicate that fruit cracking is associated with fluctuating soil moisture levels. Soil moisture variations are influenced by irrigation practices, and an irrigation regime employing frequent applications of water will lessen variations in soil moisture. A field study was initiated to study the effect of trickle irrigation regime on fruit cracking in `Celebrity' tomatoes (Lycopersicon esculentum Mill). In the three treatments used, soil was allowed to dry to 10-20, 50-60, and 100-110 centibars of tension, respectively, between watering and then was irrigated to field capacity. These tension levels corresponded with soil moisture levels of field capacity (10-20 cb), 20% of available water depleted (50-60 cb), and 40% of available water depleted (100-110 cb). Yield measurements indicated that the driest treatment (100-110 cb) significantly reduced the percent of radially cracked fruit. This treatment also significantly lowered the total yield, in terms of both fruit number and weight. There was no significant effect, however, on marketable fruit yield due to irrigation treatments. Further field studies are required to determine the optimum irrigation program to reduce fruit cracking.

Free access

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).

Free access

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

Free access

Remote areas of the United States and developing nations depend on either electric grid extension or diesel power for operating crop irrigation systems. However, electric grid extension is expensive and often impractical. Diesel pumps are expensive, polluting, and require maintenance to operate. Utilizing the energy of the sun, captured by photovoltaic panels, to power irrigation systems offers a cost-effective, pollution-free, and maintenance-free alternative. Solar-powered pumping systems are capable of delivering water from rivers or wells in volumes up to 2000 gal/min. Combining solar power with drip irrigation takes advantage of the natural coincidence of peak energy from the sun and the crop's peak need for water. In 1999, cabbage was grown comparing solar and conventionally powered drip irrigation systems at the Rutgers Univ. Snyder Research and Extension Farm, Pittstown, N.J. The solar system was operated by a 1.5-horsepower motor powered by 18 solar modules.

Free access