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David R. Hershey

John H. Patterson, founder and president of the National Cash Register Co. (now NCR Corp.), is best known for his innovative business practices which made the cash register a standard product, Less well-known was his program of industrial welfare for NCR employees which included many uses of horticulture. Illustrations of the landscaping contests Patterson sponsored in his factory neighborhoods are shown in a collection of early 1900's glass lantern slides recently discovered in the University of Maryland Horticulture Building attic. The noted Olmsted landscaping firm was hired to design the NCR factory grounds. Neighborhood children were given company land, tools, instructions, and awards, enabling them to grow vegetables to sell and to give to their families. Patterson created these `Boys Gardens' to occupy youngsters who might otherwise break windows in the NCR factory and give the factory neighborhood a bad reputation. Although his program of industrial welfare was unique in an era of worker exploitation, Patterson justified the program because “It pays”.

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N.G. Beck, M.L. Arpaia, J.S. Reints Jr., and E.M. Lord

Deformations consisting of longitudinal ridges in the rind of Citrus fruits have recently been found in Southern California Citrus groves. Here, we report the correlation between ridge formation and applications of chlorpyrifos (Lorsban, Dow Chemical Company, Midland, MI) during the feather-growth stage of bud break. All chlorpyrifos formulations resulted in significant ridging. Addition of agricultural oil and 2,4-D (2,4-dichlorophenoxyacetic acid (2,4-D) to chlorpyrifos resulted in the greatest ridging damage and widened the window of susceptibility by 2 weeks in 1988. In 1989, no significant difference was seen between treatments of chlorpyrifos, although all were significantly greater than the control. The susceptible stages of bud growth are described, as are the non-susceptible stages which precede and follow it. Floral buds in which carpels are initiating are susceptible to fruit ridging upon application with chlorpyrifos. These ridges are the result of an increase in cell size of the flavedo tissue which may be the result of a polyploid chimera.

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Bruce W. Wood

Inadequate cross-pollination of pecan [Carya illinoinensis (Wangenh.) K. Koch] occurred in block-type orchards generally thought exempt from pollination-related crop losses because of an abundance of nearby potential pollinizers. “Off-genotypes” appeared to be potentially major assets in such orchards due to their role as backup pollinizers; hence, their presence insures against crop losses due to poor pollination. Fruit-set in `Desirable' main crop rows declined sigmoidally as distance from 'Stuart' pollinizer rows increased. For 15.4-m row spacings, rate of decrease was maximum between 49 and 78 m, depending on crop year. Maximum fruit-set was in rows immediately adjacent to the pollinizer. Tree age/size and spring temperature influences on the characteristics of flower maturity windows are probably primary factors contributing to pollination-related fruit-set losses in block-type orchards relying upon pollen from a single complementary pollinizer or from neighborhood trees. For example, flower maturity was earlier in older/larger trees, and higher spring temperatures accelerated catkin development relative to that of pistillate flowers. Maximum fruit-set occurred when pistillate flowers received pollen around 1 day or less after becoming receptive, whereas no fruit-set occurred when they were pollinated around four or more days after initial receptivity. These findings indicate that many block-type orchards in the southeastern United States are exhibiting pollination-related crop reductions and that future establishment of such orchards merits caution regarding the spatial and temporal distribution of pollinizers.

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Christopher Lindsey, Gary Kling, and Mark Zampardo

UIPLANTS is a program developed under Microsoft Windows to help students in woody plant materials courses. Its many options include an encyclopedic format that displays 256-color high-resolution images of plant identification characteristics and ornamental features coupled with text, side by side image comparisons, “book markers” to return to selected screens, and a slide show that runs a display of images in a user-defined format. The system is being used to study how students learn information presented to them through computers and which program features are most effective in improving plant knowledge. Through computer logging of all student activity within the program and surveys given to the test groups, some basic usage patterns were derived. Students using the program with no incentive tended to use the program in a more comprehensive manner, switching back and forth between the slide show and encyclopedic entries with equal time spent in each. The comparison and “bookmark” features were used but less frequently. Half of the students, given an extra credit incentive based on time, followed this same usage pattern, but the other half simply used the slide show with minimal student–computer interaction.

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Thomas Björkman

Buckwheat has historically been used to suppress weeds and improve soil condition, but many of the tricks to success have been lost to history. Buckwheat is inexpensive and particularly effective in short windows between crops. We are documenting the techniques of existing experts and complementing that with research. We surveyed northeastern vegetable and strawberry growers to identify what information they need in order to feel confident that they could succeed with a buckwheat cover crop. Top questions include seed availability, types of weeds controlled, relation to other cover crops, volunteer management, and herbicide tolerance. One question tested experimentally was how to establish a full stand with minimum cost. We tested the minimum tillage requirement following pea harvest. No-till resulted in good emergence but slow growth, and dominance by weeds. Disk incorporating the pea residue resulted in excellent growth, which was not further enhanced by chisel plowing before disking. Buckwheat seedlings are intolerant of waterlogging, so deeper tillage may be important in wet years. Sowing buckwheat immediately after tillage resulted in emergence of 35%, leaving gaps large enough for weeds to grow. Waiting 1 week gave an 80% stand and complete weed suppression. Waiting 2 weeks also gave an 80% stand, but weed growth was advanced enough that weed suppression was incomplete. Therefore, a buckwheat cover crop following early vegetables requires light tillage to permit root growth, and up to a week of decomposition. If those provisions are made, complete weed suppression is obtainable.

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Michael B. Thomas, Jonathan H. Crane, James J. Ferguson, Howard W. Beck, and Joseph W. Noling

The TFRUIT·Xpert and CIT·Xpert computerbased diagnostic programs can quickly assist commercial producers, extension agents, and homeowners in the diagnosis of diseases, insect pest problems and physiological disorders. The CIT·Xpert system focuses on citrus (Citrus spp.), whereas the TFRUIT·Xpert system focuses on avocado (Persea americana Mill.), carambola (Averrhoa carambola L.), lychee (Litchi chinensis Sonn.), mango (Mangifera indica L.), papaya (Carica papaya L.), and `Tahiti' lime (Citrus latifolia Tan.). The systems were developed in cooperation with research and extension specialists with expertise in the area of diagnosing diseases, disorders, and pest problems of citrus and tropical fruit. The systems' methodology reproduces the diagnostic reasoning process of these experts. Reviews of extension and research literature and 35-mm color slide images were completed to obtain representative information and slide images illustrative of diseases, disorders, and pest problems specific to Florida. The diagnostic programs operate under Microsoft-Windows. Full-screen color images are linked to symptoms (87 for CIT·Xpert and 167 for TFRUIT·Xpert) of diseases, disorders, and insect pest problems of citrus and tropical fruit, respectively. Users can also refer to summary documents and retrieve management information from the Univ. of Florida's Institute of Food and Agricultural Sciences extension publications through hypertext links. The programs are available separately on CD-ROM and each contains over 150 digital color images of symptoms.

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Guochen Yang, Paul E. Read, and Marihelen Kamp-Glass

Chestnut (Castanea spp.) is considered difficult to micropropagate. The timing for harvesting explant materials from forced stems is critical, although many factors need to be considered for successful micropropagation. Previous research with spirea and five-leaf aralia demonstrated that forcing solution techniques extended the availability of high-quality explant material, thus expediting micropropagation. However, preliminary research illustrated that chestnut is very difficult to force and the new forced softwood growth is very short-lived, which made micropropagation difficult. It was found that, at about 7 days from budbreak, the forced chestnut softwood growth (about 2 cm long) served as the best explant material. If longer than this timing window, the new growth would die. If shorter, the explants had a high contamination rate, exudation of purported phenolic compounds, and explants would not regenerate. Shoot proliferation and callus regeneration were achieved by culturing good-quality explants on Woody Plant Medium supplemented with 0.1 mg BA/liter. The new shoots grew vigorously in vitro with apparent normal morphology.

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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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Timothy K. Broschat

Royal palms [Roystonea regia (HBK.) O.F. Cook], coconut palms (Cocos nucifera L. `Malayan Dwarf'), queen palms [Syagrus romanzoffiana (Chamisso) Glassman], and pygmy date palms (Phoenix roebelenii O'Brien) were grown in a rhizotron to determine the patterns of root and shoot growth over a 2-year period. Roots and shoots of all four species of palms grew throughout the year, but both root and shoot growth rates were positively correlated with air and soil temperature for all but the pygmy date palms. Growth of primary roots in all four species was finite for these juvenile palms and lasted for only 5 weeks in royal palms, but ≈7 weeks in the other three species. Elongation of secondary roots lasted for only 9 weeks for coconut palms and less than half of that time for the other three species. Primary root growth rate varied from 16 mm·week-1 for coconut and pygmy date palms to 31 mm·week-1 for royal palms, while secondary root growth rates were close to 10 mm·week-1 for all species. About 25% of the total number of primary roots in these palms grew in contact with the rhizotron window, allowing the prediction of the total root number and length from the sample of roots visible in the rhizotron. Results indicated that there is no obvious season when palms should not be transplanted in southern Florida because of root inactivity.

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M.E. Valverde, P. Fallah Moghaddam, M.S. Zavala-Gallardo, J.K. Pataky, O. Paredes-Lopez, and W.L. Pedersen

Ear gall development was evaluated after inoculating sweet corn (Zea mays L.) hybrids with Ustilago maydis (DC) Corda by injecting sporidial suspensions into silk channels when silks had emerged ≈3 to 6 cm from ear shoots. Gall incidence was ≈35% in two inoculation trials. About 0.5% of the noninoculated control plants was infected. Gall weight increased ≈250% to 500% between 14 and 21 days after inoculation, reaching a maximum of ≈280 to 600 g. Gall tissue was nearly 100% black and had lost its spongy integrity 19 to 21 days after inoculation, when mycelial cells formed powdery teliospores. A 1- or 2-day harvest window during which huitlacoche yield and quality were optimized corresponded to the time at which 60% to 80% of the gall tissue was black. The optimal huitlacoche harvest time varied among hybrids from 17 to 19 days after inoculation, but we suspect that optimal harvest time varies from ≈15 to 24 days after inoculation, depending on the growth stage at which the host is inoculated and the environmental conditions following inoculation. Differences among sweet corn hybrids in gall incidence, gall size, and coverage of mature galls by husk leaves were observed and could be used to select sweet corn hybrids that are well suited for producing huitlacoche.