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C.A. Powell, R.R. Pelosi, M.S. Burton, P.A. Rundell, M.A. Ritenour, and R.C. Bullock

The effectiveness of seven different aphid control regimes in delaying movement of decline (DI) and nondecline (NDI) inducing isolates of citrus tristeza virus (CTV) into a CTV-free sweet orange scion on sour orange rootstock block was monitored annually for 5 years beginning in 1999, 2 years after the introduction of the brown citrus aphid (BrCA) into the region. After 5 years, the mean percentages of infection with DI CTV were 19, 19, 17, 29, 23, 19, or 14 for trees treated annually with imidocloprid, every 6 months with imidocloprid, every 3 months with imidocloprid, every 2 months with imidocloprid, annually with Temik, annually with Meta Systox-R, or untreated, respectively. The mean percentages of infection (after 5 years) with only NDI isolates of CTV for the seven treatments were 40, 31, 33, 38, 38, 38, or 33. There was no significant difference (after 5 years) among either the DI or NDI CTV treatment means. The overall 5-year infection percentage for DI CTV (20%) was somewhat lower than that reported before the introduction of the BrCA (27%) (11). Aphid densities (Toxoptera citricidus and Aphis spiraecola) varied considerably from year to year. Good aphid control was achieved with all four imidocloprid treatments, but not with Temik or Meta Systox-R. The level of aphid control did not influence overall CTV infection percentages.

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Anna L. Testen, Delphina P. Mamiro, Hosea D. Mtui, Jackson Nahson, Ernest R. Mbega, David M. Francis, and Sally A. Miller

smallholders in Morogoro. Introduction of elite inbred germplasm or hybrid cultivars through MBT could increase tomato productivity, especially given the diversification and growth of various ‘Roma’ tomato breeding programs. The use of inbred lines is the only

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Kathleen Delate, Andrea McKern, Robert Turnbull, James T.S. Walker, Richard Volz, Allan White, Vincent Bus, Dave Rogers, Lyn Cole, Natalie How, Sarah Guernsey, and Jason Johnston

only for products with the certified organic label. These premium prices for both local and exporting organic apple growers must be continued to meet production costs ( Bertschinger et al., 2004 ). The introduction and use of scab-resistant cultivars

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D. C. Sanders

We instituted a series of on-farm trials to introduce vegetable growers to plasticulture systems. Initial trials were large areas where all combinations of plastic mulch, soil fumigation with methyl bromide, and drip irrigation were compared. As the system developed 0.4 Ha trials were instituted to show system potentials. Later 0.1 Ha trials were used to reduce resource demand. Low volume wells were used as a water source for drip irrigation. Often a simple venturi was used to apply fertilizer. Sand filters were made portable by placing them on a trailer and other equipment was made more portable. As more growers adopted the system demonstration became more complex and the focus changed to developing a total, intensive cropping system. In 10 year 50 demonstrations were conducted with a high of 18, and the hectarage of plasticulture increased from 100 Ha to 3500 Ha or from 0.1% to 8% of the appropriate crops. Yields were increase 2 to 6 times with similar improvements in quality.

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Kathryn Orvis

Advances in biotechnology are rapidly changing the way we work and live, but are often met with controversy or raise ethical questions. Approaches that enhance learning and awareness of biotechnology are essential to increasing citizen understanding of these topics. Educators, both formal and informal, need skills to understand the science associated with these technologies, as they may not have been previously exposed to the topics in their training, especially with the rapidly changing science. To address the need for unbiased agricultural biotechnology information, a graduate level internet-based course was developed entitled: “Introduction to Agricultural Biotechnology”. This course focuses on agricultural biotechnologies related to horticulture and plant science. Online courses are especially useful for students not able to travel due to various constraints, such as working full-time or being physically distant from campus. The goal is a population better able to understand the science behind rapidly advancing biotechnologies and that is better equipped to make informed decisions regarding those technologies. Course assignments are designed to help students as they teach others about topics associated with biotechnology in both formal and informal settings, such as a high school class or an Extension seminar. In the past 5 years, 54 students (teachers, college instructors, or Extension staff) from across the United States have taken the course. Course ratings have been consistently very good (avg. 4.45) on a 1–5 scale (1 = very poor, 5 = excellent). Former students have indicated that they have a better understanding of biotechnology and would be better able to relate it to others. Students also gained an improved awareness of the resources that are available for teaching agricultural biotechnology.

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H.C. Wien

Crops and Environmental Change: An Introduction to Effects of Global Warming, Increasing Atmospheric CO 2 and O 3 Concentrations, and Soil Salinization on Crop Physiology and Yield. 2005. S.G. Pritchard and J.S. Amthor. Food Products Press

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Katharina S. Wigg and Irwin L. Goldman

Ogoshi, A. 1996 Introduction: The genus Rhizoctonia , p. 1–9. In: B. Sneh, S. Jabaji-Hare, S. Neate, and G. Dijst (eds.). Rhizoctonia species: Taxonomy, molecular biology, ecology, pathology, and disease control. Kluwer Academic Publishers, Dordrecht

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Milt McGiffen

Consumption and production of organic food has quadrupled since 1990. Certified organic or pesticide-free produce and other foods are common in most grocery chains. Increased consumer demand and concerns about pesticide use has led to mandates for national standards and local implementation. The Organic Horticulture Colloquium addresses organic certification, production, pest management, consumer demand, education, marketing, and economics. Challenges and results in implementing policy and encouraging change will be related from both national and local perspectives. While the “organic movement” was originally focused on food crops, it has evolved to address issues of pesticide use in non-food horticultural crops as well. This colloquium addresses issues of concern to food and non-food agricultural products.