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  • Author or Editor: P.J. Stoffella x
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Three perennial species, wine sage (Salvia spp. Sell x roenen Schultes `Van Houttei'), blue anise sage (Salvia gauranitica St.-Hil. Ex Benth. `Black and Blue'), and indigo spires salvia (S. longispicata Martius Galeotti × S. farinacea Benth. `Indigo Spires') were transplanted in containers filled with a biosolid-yard waste compost, a commercial peat-based mix, or a mixture of 1 compost: 1 peat-based mix by volume) and grown under ebb-and-flow, drip, or manual irrigation systems. Initial physical, chemical, and elemental analyses of the media indicated that compost alone had higher pH, electrical conductivity (EC), total porosity (TP), bulk density (BD), particle density (PD), N, C, P, Ca, Zn, Cu, Fe, and B; lower initial moisture, Mg and Al; and similar Mn contents than did the 100% peat-based medium. Heavy metal (Cd and Pb) contents of compost did not exceed EPA 503 Rule limits for biosolid usage. After 6 weeks, plants were measured for leaf nutrient content, growth (leaf and stem dry weights, stem lengths), and quality (number of flowers, leaf greenness, and subjective quality ratings). At 6 weeks, plants grown in 50% or 100% compost generally had higher leaf K, P, and Mn; similar N and Ca; and lower Mg, Fe, and Al content than plants grown in the 100% peat-based medium. Plants grown in media amended with compost generally produced similar or slightly smaller plants (stem weight, leaf weight, and stem length) than when grown in peat-based media. Plants irrigated by ebb and flow resulted in higher (`Van Houttei') or similar (`Indigo Spires') dry stem weights than plants irrigated manually or with drip irrigation. Plants grown in compost had leaf SPAD readings (leaf greenness), number of flowers, and visual quality ratings that were generally similar (`Indigo Spires') or slightly reduced (`Van Houttei') than plants grown in peat-based media. However, for each species (except for `Van Houttei' grown in 50% compost using drip irrigation), plants were of marketable quality, regardless of irrigation system or medium. This study suggests that compost may serve as a viable alternative substrate for peat in the production of containerized perennials using ebb-and-flow, manual, or drip irrigation systems.

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Growth of golden shrimp plant (Pachystachys lutea Nees.) transplants was evaluated in media containing 0%, 25%, 50%, 75%, or 100% compost derived from biosolids and yard trimmings. A commercial coir- or peat-based media was amended with compost. As compost composition in the peat or coir-based media increased from 0% to 100%, carbon/nitrogen ratios decreased; and media stability, nitrogen mobilization, pH, and electrical conductivity increased. Bulk density, particle density, air-filled porosity, container capacity, and total porosity increased as more compost was added to either peat- or coir-based media. Plants grown in media with high volumes of compost (75% or 100%) had less leaf area and lower shoot and root dry weight compared to the controls (no compost). Regardless of percentage of compost composition in either peat or coir-based media, all plants were considered marketable after 8 weeks.

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Abstract

Successive plantings were made from August through October in southeastern Florida to compare plant establishment methods and their effects on stand establishment, plant growth, and maturation (time to anthesis) of bell pepper (Capsicum annuum L.). Direct-seeding treatments were germinated seeds planted in potassium starch acrylamide (PSA) gel, magnesium silicate clay (MSC) gel, plug-mix, MSC gel mix, PSA gel mix. Nongerminated seeds were covered with soil or plug-mix. Three types of containerized transplants were used for comparison of earliness to flowering. Regardless of planting date, the PSA gel mix treatment generally led to earlier emergence and more uniform plant stands compared with the other direct-seeding techniques tested. Fluid drilling with PSA (without plug-mix) typically led to reduced plant stands, whereas all other direct-seeding methods did not differ in stands. Plant dry weights were increased as much as 100% when seeds were sown in PSA gel mix rather than with other seeding treatments. Plants established by transplanting began flowering at least 16 days earlier than plants established via direct seeding. Direct-seeding germinated seeds in PSA gel mix or plug-mix led to earlier, more uniform anthesis than sowing nongerminated seeds in soil.

Open Access

`South Bay' lettuce transplants were grown in F392A styrofoam Speedling® flats at different levels of N to evaluate the effect of N on transplant quality and subsequent yield and head quality in the field. Plants were irrigated eight times over a 4-week growing period by floating flats for 30 min in nutrient solution containing eight 0, 15, 39, 45, or 60 mg·liter–1 N supplied from NH4NO3. Dry shoot mass, leaf area, and plant height increased linearly with increasing N rates and dry root mass and stem diameter increased in a quadratic fashion. Transplants with the greatest plant biomass were, therefore, produced with 60 mg·liter–1 N. Plants from the 15, 30, 45 and 60 mg·liter–1 N treatments were planted in sandy soil in plastic-mulched beds under drip irrigation. To optimize lettuce head maturity among the treatments, plants from the N treatments were harvest 53, 56, and 59 days after transplanting (DAT). The optimum time to harvest was determined to be 56 DAT. There was no yield response (measured in terms of head mass) or quality response (measured in terms of head height, head diameter, head compactness or core length) to N applied during transplant production. This indicated that transplants produced with 15 mg·liter–1 N gave equally good yield to those produced with 30, 45, or 60 mg·liter–1 N when N was applied via flotation irrigation.

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Control of downy (Pseudoperonospora cubensis) and powdery [(Podosphoera xanthii (Sphaerotheca fuliginea)] mildew on `Sweet Dumpling' winter squash (Cucurbita maxima) was evaluated at the University of Florida, IFAS, Indian River Research and Education Center (IRREC), in Fort Pierce, Florida during the Spring of 2005. Three foliar spray fungicide treatments were evaluated against an untreated control. Powdery and downy mildew ratings (estimated percentage of foliage damage) and marketable yields (mt/ha) were measured. Plants in the untreated plots had significantly higher powdery and downy mildew ratings. All fungicide treatments significantly reduced both mildews. There were no significant differences among treatments for marketable yield. Although the level of disease occurrence was not sufficient to reduce yields, Gavel alternated with Nova, Bravo Ultrex weekly, and Cabrio + Forum alternated with Bravo Ultrex + Manzate 75WG reduced downy mildew by ≥50%.

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Control of downy (Pseudoperonospora cubensis) and powdery mildew [(Podosphoera xanthii (Sphaerotheca fuliginea)] on `Sweet Dumpling' winter squash (Cucurbita maxima) was evaluated at the University of Florida, IFAS, Indian River Research and Education Center (IRREC) in Fort Pierce, Florida during Spring 2004. Seven foliar spray fungicide treatments were evaluated against an untreated control. Powdery and downy mildew ratings (estimated percentage of foliage damage) and marketable yields (mt/ha) were measured. Plants in the untreated plots had significantly higher powdery and downy mildew ratings. All fungicide treatments reduced powdery mildew on adaxial leaf surfaces. Downy mildew appeared unusually late in the crop season and all fungicide treatments significantly reduced it. There were no significant differences among treatments for marketable yield. Although the level of disease occurrence was not sufficient to reduce yields, each foliar spray treatment significantly reduced powdery and downy mildew.

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Abstract

Root morphological characteristics of ‘Redkote’ and ‘Redkloud’ kidney bean plants (Phaseolus vulgaris L.) were measured during 2 growth stages at 5, 10, 15, and 20 cm within-row spacings under field conditions. Significantly higher total root weight, shoot weight, basal root weight, and stem and hypocotyl diameters of individual plants occurred as within-row spacing increased. Uprooting resistance, taproot weight, and taproot diameter increased as within-row spacing increased up to 15 cm followed by a nonsignificant increase at 20 cm. No differences in adventitious root weight or shoot:root ratios occurred among within-row spacing treatments. ‘Redkote’ root parameters were significantly higher than those of‘Redkloud’, with the exception of adventitious root weight and uprooting resistance. Seed yields were highest for 15 cm spacing although not significantly more than at 5 cm spacing. All parameters with the exception of basal root number were significantly lower during anthesis when compared with full pod fill growth stage.

Open Access

Compost amendment to agricultural soils has been shown to either reduce disease incidence, conserve soil moisture, control weeds or improve soil fertility. Application of compost can range from 5 to 250 Mt·ha–1 (N content up to 4%). Large application of compost with high N and P levels may result in excessive leaching of nitrate, ammonium, and phosphate into groundwater. It could be a serious concern on the east coast of Florida with its high annual rainfall and shallow water table. In this study, five composts (sugarcane filtercake, biosolids, and mixtures of municipal solid wastes and biosolids) were collected from different facilities throughout Florida. Composts were applied on a surface of 15-cm sandy soil columns at the rate of 100 Mt·ha–1 on the surface basis and leached with deionized water by 300 ml·d–1 for 5 days (equivalent to 34 cm rainfall). The concentrations of NO3-N, NH4-N, and PO4-P in leachates reached as high as 246, 29, and 142 mg·L–1, respectively. The amount of N and P leached following 5-day leaching events accounted for 3.3% to 15.8% of total N and 0.2% to 2.8% of total P as inorganic forms.

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`Solar Fire' is a heat-tolerant hybrid tomato (Solanum lycopersicum L. formerly Lycopersicon esculentum Mill.) with resistance to all three races of Fusarium wilt incited by Fusarium oxysporum f. sp. lycopersici Sacc. Snyder & Hansen. It has superior fruit-setting ability in comparison with most existing cultivars under high temperatures (>32 °C day/>21 °C night), and the fruit crack less under the rainy field conditions often present in the early fall Florida production season. Fla. 7776 is the pollen parent in `Solar Fire', providing much of the heat tolerance in this hybrid. It has large fruit-providing breeders with a parent to produce heat-tolerant hybrids with two heat-tolerant parents.

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External and internal tomato irregular ripening (TIR) symptoms have been associated with the feeding of silverleaf whitefly (SLW), Bemisia argentifolii Bellows and Perring. Soil drench application of gibberellic acid (GA3) (100 ppm, Trial 1 and 2) and cycocel (CCC) (2000 ppm, Trial 1; 1000 ppm, Trial 2) were applied to dwarf cherry tomato (Lycopersicon esculentum) in the presence and absence of SLW to mimic the TIR disorder induced by the SLW. Application of GA3 induced external and internal TIR symptoms similar to the SLW-induced disorder in `Florida Petite'. There were essentially no TIR symptoms in fruit treated with CCC, an inhibitor of GA biosynthesis. In Trial 1, internal white tissue in GA3, SLW, and CCC treatments was expressed in 97%, 95%, and 4% of the total fruit, respectively. Incidence of external TIR symptom was highest (56%) in the GA3 plus SLW treatment. In Trial 2, GA3 application in the presence (83%) or absence (85%) of SLW resulted in the highest incidence of fruit with internal white tissue. External TIR symptoms induced by GA3 in the presence and absence of SLW were reduced with CCC application. These results suggest that the TIR disorder in tomato is induced by the SLW may be a GA3-regulated disorder.

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