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  • Author or Editor: Stephen R. Kostewicz x
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For many years, the former Vegetable Crops Department, now the Horticultural Sciences Department, at the University of Florida offered a vegetable crop industries course. This one-credit course is offered each year as a 3- to 5-day field trip into vegetable production areas of Florida in the spring semester during spring break. The intent of the course is to give undergraduate students an extensive on-site evaluation of the application of scientific principles learned in lectures related to Florida's commercial vegetable industry. A new, innovative approach to structuring this course was initiated recently wherein only alumni of the department interacted with the students on all phases of commercial vegetable agriculture in Florida. These alumni had obtained degrees at the BS, MS, or PhD level and represented many professional backgrounds related to producing, handling, and marketing vegetables. Students were exposed to real-life situations and were encouraged to discuss and seek employment opportunities during the farm visitations. Student expenses were offset by donations from the Florida vegetable industry.

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Two field studies were conducted in Fall 1982 and Spring 1983 to evaluate two row arrangements (single vs. double rows per bed), four within-row plant spacings (0.30, 0.45, 0.60, and 0.75 m), and three N rates for zucchini squash (Cucurbita pepo var. melopepo L.) grown on sandy soils. Rates of 67, 134, and 202 kg N/ha were used in the fall, while 134, 202, and 268 kg N/ha were used in spring to determine the optimum levels of N for the higher population densities. Early and total marketable yields were higher with double rows in the spring experiment. Decreasing in-row plant spacing from 0.75 to 0.30 m increased total yield in both experiments, but decreased early yield in the fall experiment. Total yields increased as the N rate increased from 67 to 202 kg·ha-1, but then decreased at 268 kg·ha-1. Combinations of row arrangements and within-row plant spacings allowed testing of seven populations ranging from 11,111 to 55,556 plants/ha. The overall response of yield to increasing plant densities was linear in the fall, but quadratic in the spring, when the higher rates of N were used.

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Cupric hydroxide, copper ammonium carbonate, basic copper sulfate, mancozeb, and a combination of cupric hydroxide and mancozeb were applied to American black nightshade (Solanum americanum Mill) before treatment with paraquat at 0.6 kg a.i./ha. Paraquat efficacy was reduced by all fungicides/bactericides, except a flowable formulation of basic copper sulfate, when compared to the herbicide only control. Compared to a surfactant only control, efficacy 1 week after paraquat application ranged from 86% with paraquat only to 42% with a combination of mancozeb and cupric hydroxide. Mancozeb and mancozeb in combination with cupric hydroxide resulted in greater shoot dry weight than the paraquat only control when measured 2 weeks after herbicide application. Chemical names used: 1,1'-dimethyl-4-4'-bipyridinium ion (paraquat); Mn, Zn ethylene bis diethyldithiocarbamate (mancozeb).

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Three irrigation treatments (none, drip, and sprinkler) and eight rowcover treatments were evaluated for their capacity to provide freeze protection for strawberries (Fragaria ×ananassa Duch.) in a split-plot factorial field experiment. The period under study included 20 freeze events, two events with minima of -9.5C and -10.0C. With no freeze protection, up to 93% of the flowers were damaged by freezes. Among sprinkler-irrigated plants, an average of only 10% flowers were damaged due to the freezes. Heavy-weight rowcovers (polyethylene blanket and polypropylene, 30 and 50 g·m-2, respectively) protected strawberry flowers as well as sprinkler irrigation to -4.4C. Early yield (December-January) from unprotected plants was negligible. Early yields from plants protected with a 3.2-mm polyethylene blanket or a 50 g·m-2 polypropylene cover were equal to yields obtained with sprinkler-protected plants. Combinations of sprinkler and certain rowcover treatments provided for better fruit production than either treatment alone. Drip irrigation alone provided no protection from freezes. All strawberry plants recovered from freeze damage and total-season yields were similar with all irrigation methods and rowcovers.

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