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Michael A. Fidanza and Peter H. Dernoeden

Rhizoctonia blight (RB), incited by Rhizoctonia solani Kühn, is a common disease of cool-season turfgrasses. This 2-year field study was conducted to determine the influence of N source, N application timing, and fungicide treatment on RB severity in `Caravelle' perennial ryegrass (Lolium perenne L.). Ringer Lawn Restore (Ringer), a slow-release N source, was compared to water-soluble urea. Nitrogen was applied according to either a spring (March, May, June, and September) or fall (September, October, November, and May) schedule. Plots received either N only or N plus the fungicide iprodione (3.1 kg a.i./ha applied at 21-day intervals). RB was reduced with fall-applied Ringer compared to spring-applied urea in both years in fungicide-free plots. Nitrogen generally enhanced foliar mycelium growth and RB during the initial infection periods (i.e., late June to late July). By mid- to late August there were extremely high levels of blighting among all fungicide-free treatments. Nitrogen source and N application time had no effect on the level of blighting in iprodione-treated plots. During early disease outbreaks, iprodione did not always prevent foliar mycelium from appearing, but it did protect turf from severe RB. Iprodione reduced blighting, but the level of disease suppression and resulting turfgrass quality provided on the extended spray interval was not acceptable for high-quality golf course fairways. Chemical name used: 3-(3,5-dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidine carboxamide (iprodione).

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Lewis Jett*, Edward Carey, and Laurie Hodges

There is great interest by horticulture producers in the Central Great Plains in methods to extend the traditional growing season, increase value of crops and provide more locally grown produce. High tunnels are low-cost, unheated greenhouses that can accomplish these goals. In 2002, the Central Great Plains High Tunnel Project was initiated through funding support by the Initiative for Future Agriculture and Food Systems (IFAFS). The Univ. of Missouri, Kansas State Univ., and the Univ. of Nebraska have constructed 24 high tunnels to conduct research on vegetables, small fruits and cut flowers. Each year, a multi-state workshop is conducted along with several on-farm and research center tours. Growers are collaborating with extension personnel on projects ranging from high tunnel temperature management to pest management. A web site for high tunnel information has been constructed (www.hightunnels.org). Production guides on specific high tunnel crops have been printed. From 2002-03, a significant number of high tunnels have been constructed in the Central Great Plains.

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J. R. Heckman, D. J. Prostak, and W. T. Hlubik

The presidedress soil nitrate test (PSNT) is an in-season soil test that evaluates the N supplying capacity of soil before side dressing to adjust N application rates. Increasing acceptance of this soil test among field corn growers in New Jersey has shown it to be an effective practice. Nitrogen application rates were reduced by an average of 45 kg-1 ha without loss of crop yield. Field calibration research to extend use of the PSNT to sweet corn has the potential to improve N fertilizer recommendations for this crop. A critical concentration of 25 mg kg-1 NO3-N in the surface 30 cm of soil is generally considered adequate for field corn. Certain crop features of sweet corn (earlier harvest, smaller plant size and population) suggested that the critical NO2-N level might be lower than for field corn while market quality suggested that it might be a higher value. Results from 40 sweet corn field calibration sites in New Jersey indicate that the PSNT critical soil NO3-N concentration may be greater for sweet corn than field corn. A preliminary critical level of 30 mg kg-1 NO3-N in the surface 30 cm of soil is suggested for use of the PSNT on sweet corn. Further research is being conducted to improve sidedress N recommendations based on the PSNT.

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Adam Montri, William J. Lamont Jr., and Michael D. Orzolek

High tunnels offer growers in temperate regions the ability to extend the production season. Past research has shown that these low-input structures also reduce disease and pest pressure. These characteristics make high tunnels extremely attractive to organic growers. Tomatoes (Lycopersiconesculentum Mill.) are the crop most often produced in high tunnels in Pennsylvania and many producers are interested in combining both high tunnel and organic production methods. Growers may be hesitant to transition to organic production due to conceptions concerning reduced yields specifically during the 3-year transition period to USDA certified organic status. A field trial investigating tomato production in high tunnels during the first year of organic transitioning was conducted in 2004 at The Penn State Center for Plasticulture, Russell E. Larson Agricultural Research Center, Rock Springs, Pa. The objective of this research was to evaluate yield of the four cultivars Big Beef, Mountain Fresh, Plum Crimson, and Pink Beauty in an organic system relative to a scheduled fertilization/irrigation regime and a fertilization/irrigation regime employed using T-Systems International's Integrated Agronomic Technology. Data collected included total weight, total fruit number, weight by grade, fruit number by grade, total marketable yield, and fertilizer and water usage. Yield across cultivars ranged from 4.96 kg/plant to 6.83 kg/plant. `Pink Beauty' exhibited the lowest yields in both treatments, while `Plum Crimson' and `Mountain Fresh' exhibited the highest yields in the IAT and scheduled treatments, respectively. This experiment will be repeated in 2005 to further evaluate the performance of these cultivars.

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G. Tehrani and W.D. Lane

Sweet cherry breeding started at Vineland and Summerland in 1915 and 1924 and has resulted in the naming and introduction of 11 and 18 cultivars, respectively. `Victor' and `Van' were the first cultivars named from Vineland and Summerland, respectively, in 1925 and 1944. `Van' has become a popular cultivar in North America and Europe. The main objective in these breeding programs has been to develop cultivars that produce large quantities of firm-fleshed, crack-free, flavorful, large, black cherries with a range of maturity dates to extend the season of harvest. In the 1960's, the development of self-fertile cultivars was added to the objective of the programs. Already several self-fertile cultivars and advanced breeding selections have been named and introduced from Canada. The programs have also contributed to the assignment of cultivars to different pollen-incompatibility groups and verification of pedigree of sweet cherry cultivars. The impact of these long-term breeding programs in Canada and abroad will be discussed in detail.

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J.M. Goatley Jr., V.L. Maddox, D.L. Lang, R.E. Elmore, and B.R. Stewart

The ability of a temporary turf cover and foliar-applied iron (Fe) to sustain or promote bermudagrass (Cynodon dactylon (L.) × transvaalensis Burtt-Davy `Tifway' growth beyond its normal growing periods in central Mississippi was evaluated during the fall, winter, and spring seasons of 1998-2001. The application of a polypropylene turf blanket when night temperatures were predicted to be ≤4 °C extended acceptable bermudagrass turf quality by 5 to 8 weeks in the fall and winter period as compared to the uncovered control plots. Also, complete green-up of the turf occurred 4 to 6 weeks earlier the following spring. There was no enhancement in bermudagrass quality by temporarily covering at predicted night temperatures of ≤15 or ≤9.5 °C. Foliar applied iron (Fe) further enhanced turf quality in the fall and winter months, but resulted in no visible turf response the following spring. Total nonstructural carbohydrate (TNC) concentrations in rhizomes that were sampled during November, January, and April 2000 and 2001 were generally increased by the cover application as compared to the uncovered control. Foliar Fe applications did not influence TNC levels.

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Loretta J. Mikitzel, Max E Patterson, and John K. Fellman

Walla Walla Sweet onions (Allium cepa L.) have a short storage and marketing season. Studies to determine viable shelf life and to extend post-harvest life with controlled atmosphere (CA) storage were conducted. Onions were exposed to various CA gas mixtures in combination with heat curing (35°C) and/or chlorine dioxide (ClO2) fumigation, to control disease. Preliminary results indicated Botrytis was the primary cause of post-harvest losses. A 1% O2, 5% CO2 atmosphere appeared to maintain onion quality better than other gas mixtures tested during 15 weeks of CA storage (0°C). Carbon dioxide series above 5% show promise in reducing the 35% storage loss that occurred with the 5% CO2 treatment. Curing for at least 72 hours followed by a 1-hour ClO2 fumigation resulted in the least bulb decay and after 15 weeks of storage (1% O2, 5% CO2), 75% of the bulbs were in marketable condition. Onions stored 15 weeks in air (0°C, 70% RH) were unmarketable. Shelf life of freshly harvested onions was 18 days, after which the onions rapidly decayed. After CA storage, shelf life was reduced to 10-14 days due to rapid sprouting. To enjoy a 30-day market window, disease control is necessary for freshly harvested onions and sprouting must be controlled in post-storage onions.

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J. A. Thies, P. A. Berland, and R. L. Fery

Rhizoctonia solani is an important pathogen of cowpea (Vigna unguiculata) in the southern U.S. and worldwide. Cowpeas are especially susceptible to seedling diseases caused by R. solani when planted in cold, moist, spring soils. Nine cowpea cultivars were evaluated in inoculated field tests at six planting dates in Charleston, S.C., during 2004. The cowpea cultivars evaluated were Bettergro Blackeye, Knuckle Purple Hull, Mississippi Silver, Colossus-80, Charleston Nemagreen, Texas Cream-40, White Acre, Coronet, and Charleston Greenpack. The tests were planted on 20 Apr., 29 Apr., 11 May, 19 May, 27 May, and 8 June. The experimental design for each test was a split-plot with six replicates. Whole plots were cultivars, and sub-plots were inoculation with R. solani and an uninoculated control. Rhizoctonia solani caused significant seedling losses in all cultivars evaluated during mid-April to early June and seed yields were reduced in the 11 May planting. In general, standard cowpea cultivars (Mississippi Silver, Colossus-80, and Coronet) had higher stand counts and produced heavier seed yields than other cowpea cultivars, although these standard cultivars were not resistant to R. solani. Resistant cowpea cultivars are needed to allow earlier planting of the crop in cold soils, which would extend the growing season and allow more efficient use of harvesting equipment and processing facilities.

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Yin-Tung Wang

An experiment was initiated to determine the effect of a low N, high P and K fertilizer applied during the flowering season on a hybrid moth orchid (Phalaenopsis TAM Butterfly Blume.). On 1 Sept., plants of flowering size receiving N, P, and K at 100, 44, and 83 mg·L–1, respectively, from a 20N–8.8P–16.6K soluble fertilizer were given N, P, and K, at 30, 398, and 506 mg·L–1 (high P), respectively, at each or every fourth irrigation. Control plants continued to receive the 20N–8.8P–16.6K fertilizer. The high P treatments, regardless of the frequency of application, had no effect on the date of emergence of the flowering stem (spiking), anthesis, or flower size. All plants treated with the high P fertilizer had fewer flowers (15 to 19) than the controls (24 flowers). Continuous application of adequate N appears to be more important than low N and increased P for optimal flowering. In a separate experiment using the same hybrid orchid, terminating fertilization completely on 1 Sept., 29 Sept., or 27 Oct. or when the flowering stems were emerging (1 Oct.) reduced flower count (≤19 vs. 24). Flower longevity was reduced by 12 d when fertilization was terminated on 1 Sept. Flower size was unaffected by any treatment in either experiment. Discontinuing fertilization prior to late November reduced flower count. Withholding fertilization for extended periods resulted in red leaves, loss of the lower leaves, and limited production of new leaves.

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Maria P. Paz*, Jeff S. Kuehny, Gloria B. McClure, Richard Criley, and Charles J. Graham

Ornamental gingers are popular cut flowers and have been promoted as a promising potted flower crop because of unique foliage, long-lasting colorful bracts, and few pest problems. Rhizomes are the primary means of propagation in late spring followed by shoot growth and flowering, and plants enter dormancy under short days in the fall. Termination of dormancy is important for greenhouse forcing and extending the growing season. Manipulation of rhizome storage to satisfy dormancy requires investigation into the storage environment. It appears that controlling growth, development and flowering in geophytic plants is dependent on reserve accumulation, mobilization, and redistribution. Rhizomes of four ginger species (Curcuma alismatifolia Gagnep., C. roscoeana Wallich, Globba winittii C.H. Wright, and Kaempferia galanga L.) were stored for 0 to 16 weeks at 15, 20, or 25 °C to determine the effect on growth, flowering, respiration rates, and carbohydrate content. Upon completion of treatment application, rhizomes were planted in a peat moss:bark:perlite mix and placed in a greenhouse with 25 °C day/21 °C night temperatures with 40% shade. The production time, days to emergence (DTE) and days to flower (DTF), was reduced with an increase in storage temperature and duration for all species. DTE and DTF for Globba and Kaempferia were hastened when rhizomes were stored for 16 weeks at 25 °C. For C. alismatifolia, DTE and DTF were hastened when rhizomes were stored at 25 °C for at least 10 weeks. For C. roscoeana, storage at 25 °C for 14 or 16 weeks was found to hasten emergence. The response of respiration and carbohydrate concentration was not consistent with rhizome and plant growth responses.