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Off-site movement of sediment, nutrient and agricultural chemicals from plasticulture production of green-pack tomatoes on water quality is a serious environmental concern, particularly for the clam aquaculture industry of eastern Virginia. Thus, the development of ecologically sound, economically sustainable cultural management strategies for tomato (Lycopersicon esculentum Mill.) production is needed. Two plantings were made within each of the three tomato harvest seasons [summer, bridge (late summer) and fall] in 1998 and 1999 (one summer crop in 1999). Between-bed treatments included clean culture or pearl millet [Pennisetum glaucum(L.) R. Br.] sown at bed establishment. On-bed treatments included standard plasticulture with fumigation on a 76-cm-wide bed (std), plasticulture without fumigation on a 76-cm-wide bed (std-fum), plasticulture on a 61-cmbed with fumigation (narrow) and organic mulch [wheat straw (Triticum aestivum L.) in 1998; desiccated hairy vetch (Vicia villosa Roth.) in 1999]. Total and marketable yields for the three plasticulture on-bed treatments (std, std-fum and narrow) were similar in 1998 and 1999. Yield was suppressed for the organic mulch on-bed treatments in all but the bridge plantings in 1999. Improved yield with plasticulture treatments and high market price for the summer crop in 1998 resulted in elevated crop value and return to land and management (return) compared to that of organic mulch. The return for later plantings was low, but positive. Return was negative for both bridge and the first fall crops in organic mulch in 1998. Low yields in all treatments and low prices in 1999 resulted in negative to negligible return for on-bed treatments in all but the summer planting using plasticulture. Return was consistently lower with organic mulch compared to plasticulture for the high value summer crop in Virginia with between-bed millet in 1998 and with or without millet in 1999. The use of organic mulch on the beds in this study was not economically feasible for the high value summer crops. Adjustments (desiccation of cover, control of weeds) in cultural management of the between-bed management strategy are needed before large-scale commercial implementation will occur.
Resistance to grape anthracnose [Elsinoë ampelina (de Bary) Shear] was evaluated in 13 known Vitis species and five taxonomically undescribed grapes native to China. One hundred and eight clones of Chinese Vitis species were tested under field conditions between 1990 and 1992. Berry infection did not occur in these species. Leaves displayed strong resistance to anthracnose, although intraspecific variations were observed. There was no relationship between anthracnose resistance and geographical origin of the species. Results from this study indicate that oriental grape species are useful for disease-resistance breeding.
Araza (Eugenia stipitata Mc Vaugh) is a plant from the Myrtaceae family originated from Amazonia. The postharvest behavior of its promissory fruit has been sparingly studied. Weight loss, softening, decay, and chilling injury (skin scald) at temperatures below 10-12 °C limits its shelf-life to less than 10 days. The application of calcium pretreatments slightly improved flesh firmness after 7 days at 20 °C and resulted in skin injury, particularly at concentrations higher than 4% (w/v). A warming treatment of 6, 12 or 18 h at 20 °C was applied to fruit after 6 d storage at 10 °C. Treated fruit had less scald, suppressed decay, and ripened normally after a total of 2 weeks of storage and a shelf life of 3 days.
Interactive review exercises were developed as an online learning component of an existing native plant landscaping course. The instruments were designed with specific goals for students to 1) test their plant identification knowledge, 2) practice leaf terminology with specific plant examples, and 3) associate landscape performance with native ecosystem characteristics. The plant identification tool was developed within a spreadsheet application using formulas consisting of logic statements. This tool tests the students’ ability to identify plants and spell scientific and common names associated with high-resolution plant images. The leaf terminology tool was developed using a multimedia platform. It uses a drag-and-drop interface where students are asked to associate a specific leaf term (i.e., margin, apex, base, texture, arrangement) with a scanned image that best matches the taxonomic term. The ecosystem tool, also developed using a multimedia platform, uses digital images captured for each of Florida's major ecosystems in conjunction with sets of plant combinations and site characteristics. Students select the appropriate choices and submit their answers online, after which they receive immediate feedback. Students reported an improvement in plant recognition after they had access to these identification tools. These interactive learning tools not only benefit students enrolled in this specific course but can be adapted to a variety of online courses nationwide.