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Mary Lamberts*, Eugene McAvoy, Teresa Olczyk, and Phyllis Gilreath

U.S. agricultural producers are required to provide varying amounts of safety training to their employees depending on the nature of their operation(s). Hand washing is an integral part of several types of safety training including pesticide safety education, the Worker Protection Standard and Microbial Food Safety of Fruits and Vegetables. Generally instructions are to “wash thoroughly,” though some employees are told they should wash for 20 seconds. An easy way to get growers to “buy into” methods that verify hand washing is to include such demonstrations as part of pesticide safety education programs and workshops that grant Continuing Education Units (CEUs) for the renewal of pesticide applicator licenses. It is important that the demonstrations be highly visual so participants actually experience the difficulty in removing a contaminant from hands even though they have performed “thorough” hand washing. It also allows them to observe the ease of cross contamination from soiled hands. Once growers see how easy and inexpensive it is to do this type of training, they are being encouraged to use these demonstrations with various types of employees: mixer-loaders and other handlers, harvesting crews, packinghouse employees, and even field workers who routinely handle plants and may be spreading diseases. Details on different methods of training and grower reactions will be presented.

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Monica Ozores-Hampton, Philip A. Stansly, and Eugene McAvoy

Tomato yellow leaf curl virus (TYLCV) is considered to be the most damaging tomato (Solanum lycopersicum) virus worldwide. Management of TYLCV has relied primarily on insecticidal control targeting the vector sweetpotato whitefly [SPW (Bemisia tabaci)]. However, resistance of the SPW to insecticides; increased length of the growing season, due in part to increased plantings of grape tomato; and asymptomatic hosts of TYLCV such as pepper (Capsicum annuum) have increased the need for wider use of TYLCV-resistant (TYLCV-R) varieties. The objective of this study was to evaluate horticultural characteristics of commercially available TYLCV-R varieties/advanced breeding lines of round and Roma-type tomato varieties in Florida. Sweetpotato whitefly populations and incidence of TYLCV were greater in 2007 than 2008. Under high TYLCV pressure, most of the TYLCV-R varieties/advanced breeding lines produced higher yield than susceptible varieties. In contrast, no clear advantage was found by using TYLCV-R varieties under low TYLCV pressure. Additionally, TYLCV-R varieties produced a high percentage of unmarketable fruit due to rough blossom end scars (BES), zippering, catfacing, sunscald, yellow shoulders, off shapes, and radial or concentric cracking compared with susceptible varieties in both years. Visual assessment of TYLCV-R varieties/advanced breeding lines for horticultural traits showed that ‘Security 28’, Sak 5443, and ‘Shanty’ were the best overall varieties/advanced breeding lines based on participants combined score rating, although ‘Tygress’ and Sak 5808 performed best based on empirical evaluation (numerical data) of total marketable yields and low unmarketable yield.

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Aline Coelho Frasca, Monica Ozores-Hampton, John Scott, and Eugene McAvoy

Compact growth habit (CGH) tomatoes (Solanum lycopersicum) are determinate plants with shortened internodes and strong side branching due to the brachytic gene (br) that grow either prostrate or upright as a result of unidentified gene(s). Compact growth habit tomatoes do not require staking, tying, or pruning and can potentially be mechanically harvested, lowering Florida fresh-market tomato production costs. Therefore, the objective of this study was to evaluate the effects of two planting configurations (single and double row) and breeding lines (BLs) on CGH tomato plant growth, flowering pattern, yield, and postharvest fruit quality. Two experiments were conducted in Immokalee, FL, during Spring 2013 and 2014 in a split-plot design with four replications. Planting configurations affected CGH tomato growth at midseason in 2013 but not in 2014; however, in 2014, CGH tomato vines grew outside the beds into the row middles, which is uncommon for this tomato type and undesirable. Plants of CGH tomatoes had a similar flowering pattern to a conventional upright tomato cultivar, which was unexpected. Planting configurations did not affect marketable yields in 2013, but single-row plots produced higher extra-large and total marketable yields at first and total season harvests in 2014. Total season marketable harvests ranged from 26.1 to 53.6 and 29.3 to 45.6 Mg·ha−1 in 2013 and 2014, respectively. Fla 8916 was among the highest yielding BLs, maximizing extra-large and total season marketable yields. Unmarketable fruit ranged from 22% to 31% and 25% to 52% of the total season harvest in 2013 and 2014, respectively, and the most common defects were sunscald, off-shape, catface, and graywall. All CGH evaluated may be suitable for mature-green harvest regarding postharvest fruit quality, although fruit ripening uniformity was of concern in 2014. Average CGH total season marketable yields harvested twice were lower than expected yields of staked-upright tomato cultivars that may be harvested three times, but higher than Florida average yields. However, CGH tomato total production cost can potentially be lower than staked-upright cultivars making CGH tomatoes a viable alternative for the Florida mature-green fresh-market industry to remain sustainable.

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Kent Cushman, Sanjay Shukla, Gregory Hendricks, Thomas Obreza, Fritz Roka, and Eugene McAvoy

Florida is one of the leading states in the United States in watermelon production, and on-farm management of nutrients and water is an important issue in the state. A management strategy using higher-than-recommended rates was compared to two strategies using recommended rates. A systems approach was used to define treatments: (HR) high rate of 265 pounds per acre (lb/ac) N, 170 lb/ac P2O5, 459 lb/ac K2O, and soil moisture content of 16% to 20% via seepage irrigation, (RR) recommended rate of 150 lb/ac N, 100 lb/ac P2O5, 150 lb/ac K2O, and soil moisture content of 8% to 12% via seepage irrigation, and (RR-S) equal to RR but irrigation provided by subsurface drip tubing. Large quarter-acre plots were used for each experimental unit. `Tri-X 313' was interplanted with `Mardi Gras' during Spring 2004 and with `SP-1' during Spring 2005 in a RCB design with two replications at the SWFREC in Immokalee. Leaf tissue analyses, petiole sap, and biomass accumulation were recorded each season. Watermelons were harvested at least twice each year and fruit were counted and weighed individually from three subplots within each plot. At least five fruit from each subplot were cut open for internal evaluation. Leaf nitrogen and potassium content for HR was consistently greater than that of RR or RR-S. Yields of HR were 41% to 50% greater than the two RR treatments. Yield was 1089, 704, and 775 hundred-pound units per acre (cwt/ac) in 2004 and 801, 541, and 533 cwt/ac in 2005 for HR, RR, and RR-S, respectively. Soluble solids content and hollowheart incidence were not affected by treatment. Our results indicate HR was more productive than RR or RR-S and may justify the higher inputs associated with this management strategy.

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Kent Cushman, Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Darrin Parmenter, and Teresa Olczyk

Vegetable producers in south Florida suffered the effects of four major hurricanes during 2004 and two during 2005, causing damage to crops and farms estimated at well over 1 billion dollars each year. Producers were quick to respond by replanting or nursing damaged crops back to health. Green beans and leafy crops appeared least likely to recover or produce acceptable yields after exposure to high winds and driving rains. Young tomato plants up to the second or third string were at times completely stripped of leaf material, yet recovered surprisingly quickly. A replant study showed no benefit in replanting compared to keeping damaged plants in the field. Older tomato plants were marginal in their ability to recover with 10% to 60% reductions in yield for first and second harvests when compared to yields common in the region. As much as 100% of Palm Beach County's 2005 early fall bell pepper planting was destroyed by storms. Other peppers in the region were affected by flooding and subsequent development of root diseases such as phytophthora. Damaged eggplant recovered slowly. Research plantings located in commercial fields and at Research and Education Centers were devastated. In addition to loss of crops, costs to vegetable growers included labor to remove damaged plastic and reset stakes, installation of replacement plastic mulches, replanting, and structural damage to buildings and packing facilities. Some transplant houses and greenhouses for specialty peppers were completely destroyed. Removing plastic coverings before a storm's arrival saved structures and crops. Transplants of all crops were in short supply. Labor was lacking due to reconstruction efforts in New Orleans and the Gulf Coast. Successful and not-so-successful recovery efforts will be shown.

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Russell T. Nagata, Kenneth L. Pernezny, Darrin M. Parmenter, Eugene McAvoy, and Kent E. Cushman

Twenty-five varieties of bell peppers (Capsicum annuum) were transplanted in commercial pepper fields in Immokalee and Delray Beach, Fla., to evaluate horticultural characteristics and resistance to race 3 bacterial spot of peppers caused by Xanthomonascampestris pv. vesicatoria. All cultural and management procedures were based on commercial best management practices. Eighty to 90% of marketable fruits had three or four lobes. Total marketable fruit yield from three harvests ranged from 4596 to 7089 kg·ha-1 and marketable fruit number ranged from 20,571 to 31,224 fruit/ha. Most fruit were slightly elongated with length to diameter ratios between 1.1 and 1.2. Seminis 7602 had a ratio of one, while lines ACR 252, PRO2R-3, and PR99R-16 had ratios of 1.40, 1.36, and 1.28, respectively. Significant differences were observed for fruit wall thickness, with those grown in Delray Beach having thicker fruit walls that averaged 7.5 mm vs. 5.3 mm for the Immokalee site. Bacterial spot infection at both sites did not affect yield, due to late natural infection of the field. Susceptible control `Jupiter' had a mean foliage disease incident rating of 26% after the final harvest and was surpassed only by 7682 and 8328 from Enza. The most resistant lines with disease ratings of <3% were 5776, 7141, and 8302 from Seminis, and Telstar from Hazera.

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Monica Ozores-Hampton, Eric Simonne, Fritz Roka, Kelly Morgan, Steven Sargent, Crystal Snodgrass, and Eugene McAvoy

With increasing environmental concerns, the sharp cost increase of fertilizer and the absence of a soil test to predict nitrogen (N) needs of tomato (Solanum lycopersicon L.) grown on Florida’s sandy soils, a partnership was created with growers, state agencies, and the University of Florida, Institution of Food and Agricultural Sciences (UF/IFAS). The objectives of this study were to identify a range of N rates that would result in highest yields and postharvest quality, and maximum economical return for tomato, grown with subsurface irrigation (management of a perched water table above an impermeable soil layer or hard pan) during the spring season (low probability of leaching rain events). The study was conducted in Spring 2007 and 2008 in Palmetto, FL, with N rates ranging from 22 to 470 kg·ha−1 at pre-plant as ammonium nitrate (NH4NO3). Weather conditions were typical of a dry spring season in central Florida with no leaching rain events recorded in either year; however, rain patterns were different between the 2 years. In the absence of leaching rain and frost protection (either may raise the water table), petiole sap NO3-N decreased over time and the rate of decline depended on the N fertilizer rate. Extra-large and total marketable fruits yields showed a quadratic plateau response to N rates with maximum yields at two harvests (97% of the yields) grown with 172 and 298 kg N/ha in 2007 and 2008, respectively. During subsequent ripening, N rate did not correlate consistently to fruit ripening rate, fruit firmness, nor compositional quality at table-ripe stage. The high value of tomatoes relative to the cost of N fertilizer created a situation in which the profit-maximizing rate of N was not significantly different from the production-maximizing N rate. Whether the profit-maximizing level of N was higher or lower than the UF/IFAS-recommended rate depended on the growing season. With favorable growing conditions (i.e., conditions in 2008), a grower’s net return would have decreased between $1000 and $2000 per hectare by using UF/IFAS-recommended rates depending on market conditions. However, if the UF/IFAS-recommended rate of 224 kg·ha−1 resulted in the highest yield, applying upwards of 300 kg·ha−1 would have increased grower production costs by at least $67/ha. Although fertilizer costs are known before the crop is grown, tomato prices are realized only at the end of the growing season and profit margins can only be calculated after the fact.

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Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Phil Stansly, Sanjay Shukla, Pam Roberts, Fritz Roka, and Tom Obreza

About 10,000 ha of staked tomato are grown each year in the winter–spring season in southwest Florida. Tomatoes are produced with transplants, raised beds, polyethylene mulch, drip or seepage irrigation, and intensive fertilization. With the development of nutrient best management practices (BMPs) for vegetable crops and increased competition among water users, N recommendations must ensure economical yields, but still minimize the environmental impact of tomato production. The current University of Florida–IFAS (UF–IFAS) N fertilization rate of 224 kg·ha-1 (with supplemental fertilizer applications under specified conditions) may require adjustment based on soil type and irrigation system. Because growers should be involved in the development and implementation of BMPs, this project established partnerships with southwest Florida tomato growers. Studies evaluated the effects of N application rates on yield, plant growth, petiole N sap, pests, and diseases. Nine on-farm trials were conducted during the dry winter 2004–05 season. Treatments consisted of N fertilizer rates ranging from 224 to 448 kg·ha-1, with each trial including at least the UF–IFAS rate and the traditional rate. Although total yields were comparable among N rates, there were differences in size category. Nitrogen rates had little effect on tomato biomass 30 and 60 days after transplanting. Changes in petiole sap NO3-N and K concentrations were different between seepage and drip irrigation, but usually above the sufficiency threshold. It is important to consider the type of irrigation when managing tomato and determining optimum N fertilizer rates.

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Gregory S. Hendricks, Sanjay Shukla, Kent E. Cushman, Thomas A. Obreza, Fritz M. Roka, Kenneth M. Portier, and Eugene J. McAvoy

Watermelon (Citrullus lanatus) production is concentrated in southern Florida where growers often use seepage irrigation. According to a recent survey, growers believe that nitrogen (N), phosphorus (P), and potassium (K) rates recommended by the University of Florida Institute of Food and Agricultural Sciences (UF-IFAS) are low. A study was conducted during Spring 2004 and 2005 at a UF-IFAS research farm to compare three nutrient and water management systems: high rate [HR (265, 74, and 381 lb/acre N, P, and K, respectively)], recommended rate [RR (150, 44, and 125 lb/acre N, P, and K, respectively)], and recommended rate with subsurface irrigation (RR-S). Irrigation was managed to keep soil moisture content at 16% to 20% for HR and 8% to 12% for RR and RR-S. The experimental design was a randomized complete block design with two replications and three subsample areas within each 0.25-acre plot. The HR management approach produced ≈60% to 80% higher yields (cwt/acre) during 2005 than RR or RR-S. The HR treatment produced larger watermelons than RR or RR-S in 2005. Triploid watermelon prices had to be at least $3.74/cwt to cover all costs associated with HR. The HR approach increased the grower net returns by $590/acre and $1764/acre under conservative and higher yield and price expectations, respectively. Soluble solids content and hollowheart ratings were unaffected by treatment. Total biomass, recorded during 2005, followed a similar trend as yield, with HR producing 105% and 125% greater total dry weight than RR and RR-S, respectively. Total N content of HR biomass was 56% higher than that of RR and RR-S. Total P content was 29% and 50% higher than that of RR and RR-S, respectively. Leaf and petiole tissue from the HR treatment exhibited consistently higher N and K leaf tissue values during 2005 than RR and RR-S. In conclusion, trends in the data consistently showed greater plant performance with higher rates of fertilizer and soil moisture content. Our ability to detect differences in 2005 was probably enhanced by higher rainfall during 2005 compared with 2004.

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Monica Ozores-Hampton, Eric Simonne, Eugene McAvoy, Phil Stansly, Sanjay Shukla, Fritz Roka, Tom Obreza, Kent Cushman, Phyllis Gilreath, and Darrin Parmenter

Florida tomato growers generate about $600 million of annual farm gate sales. The Florida Vegetable and Agronomic Crop Water Quality/Quantity Best Management Practices Manual was adopted by rule in the Florida Administrative Code in 2006 and describes cultural practices available to tomato growers that have the potential to improve water quality. By definition, BMPs are specific cultural practices that are proven to optimize yield while minimizing pollution. BMPs must be technically feasible, economically viable, socially acceptable, and based on sound science. The BMP manual for vegetables endorses UF-IFAS recommendations, including those for fertilization and irrigation. Current statewide N fertilizer recommendations for tomato provide for a base rate of 224 kg/ha plus provisions for supplemental fertilizer applications 1) after a leaching rain, 2) under extended harvest season, and 3) when plant nutrient levels (leaf or petiole) fall below the sufficiency range. An on-farm project in seven commercial fields was conducted in 2004 under cool and dry growing conditions, to compare grower practices (ranging from 264 to 468 kg/ha of N) to the recommended rate. Early and total extra-large yields tended to be higher with growers' rate than with the recommended rate, but these differences were significant only in one trial. The first-year results illustrated the need for recommendations to be tested for several years and to provide flexibility to account for the reality of local growing conditions. Working one-on-one with commercial growers provided an opportunity to focus on each farm`s educational needs and to identify specific improvements in nutrient and irrigation management.