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Se realizo un primer experimento para determinar el efecto de tres sustratos: mezcla comercial, estiercol descompuesto + tierra (1:1) y cachaza curada + estiercol descompuesto + tierra (1:1:1) en el numero de hojas, altura y materia seca de plantulas de lechosa. En un segundo experimento se evaluo el efecto d e los mismos tres substratos y 4 dosis de boro (0.13, 0.26, 0.39 y 0.52 mg B/planta, respectivamente) en el desarrollo de plantulas de lechosa. Los resultados indican que el numero de hojas, altura y materia seca a los 21, 28 y 35 dias despues de nacidas fue menor en las plantulas sembradas en el sustrato comercial que en los otros dos sustratos (p.05). Similarmente, en el segundo experimento las plantulas sembradas en el sustrato comercial tenian menor altura a los 4, 8 y 12 dias despues del trasplante (DDT) que en los otros dos sustratos (p.05). Se presentaron diferencias (p.05) en la altura de las plantulas a los 4, 8 y 12 DDT, entre el control (no aplicacidn de boro) y las demas dosis, indicando que el rango critico de aplicacidn de boro se encuentra entre 0 y 0.13 mg B/planta. Se sugiere la realizacidn de estudios adicionales para conocer el nivel optimo de aplicacidn de boro, dentro del rango mencionado, a plantulas de lechosa con la finalidad de maximizar la eficiencia en el uso del micronutriente.

Papaya seedlings (cv.'Sunrise') were produced under greenhouse conditions to determine the effects of combinations of varying ethanol and gibberellic acid-3 (GA3) concentrations on papaya shoot height, leaf number, leaf area, and shoot dry weight. Seedlings were grown in 0.5-L plastic containers filled with a potting medium composed of 50% vermiculite, 30% periite, and 20% spaghnum peat (v/v). When seedlings were 10 cm tall and had two-true leaves, foliar sprays of ethanol (0, 5, 10, 15 or 20% v/v) and G A3 (0, 10, 20 and 30 ppm w/v) combinations were applied using a 5-mL solution volume. Treatments were arranged in a randomized complete block design with seven replications. Ethanol and GA3 concentrations interactively influenced plant height (P0.05) on leaf number, whereas only ethanol rates affected papaya leaf area, with maximum area obtained with 5% ethanol (+32.6%). No significant ethanol by GA3 interactions (P>0.05) were observed for shoot dry weight. However, both factors individually influenced shoot dry weight. Leaf area, plant height, and seedling dry weight was higher when plants were treated with solutions containing 5% ethanol than when other rates were used, yielding 42.6% higher shoot dry weight than the untreated control. In fact, plants receiving rates of 10% ethanol or higher had a dry matter loss of at least 30% compared to untreated seedlings.

Field trials were carried out in organic soils naturally deficient in phosphorus (P) fertility to determine the effects of different fertility regimens of this nutrient and common lambsquarters initial removal times on lettuce marketable yields. Phosphorus was either banded (125 Kg P/ha) or broadcast (250 Kg P/ha) prior to lettuce planting. A single lambsquarters population density of 4 plants per 5.4 m2 was allowed to interfere with "South Bay" lettuce within each Ρ regime. Lambsquarters were removed at 2, 4, 6 or 8 weeks after lettuce emergence, along with the weed-free control. When lettuce was grown under weed-free conditions, banded Ρ increased lettuce marketable yields by 27% compared to Ρ broadcast. With banded P, no significant differences were observed between the 2 week removal and the weed-free control. On the other hand, differences were accounted between the weed-free control and the 2 week removal (aproximately 24% reduction). No differences on lettuce marketable yields occurred after 4 and 6 weeks for broadcast and banded P, respectively. Maximum yield reductions of about 47 and 51 % for banded and broadcast Ρ were measured. These findings suggest that banding Ρ in lettuce stands increase the time of lambsquarters interference necessary to reduce lettuce yields.

Three patients with renocolic fistulas are presented. Antegrade or retrograde pyelography showed the fistula in one patient but was unsuccessful in two others. CT demonstrated perinephric inflammation extending to the colon, complex air-fluid collections within the kidney, or extension of renal contrast into the colon. CT and direct pyelography complement each other for the diagnosis of renocolic fistulas.

Container experiments were conducted in the Dominican Republic to determine the effect of gibberellic acid-3 (GA3), folcysteine and kinetine on the competitive ability of eggplant against the weed purple nutsedge. Eggplant transplants were treated with the growth regulators immediately before transplanting. The rates were 25 and 50 ppm for GA3 and kinetine, and 250 and 500 ppm for folcysteine. The competitive ability of eggplant against nutsedge was determined by relative crowding coefficients (RCC) in a replacement series with five eggplant to purple nutsedge proportions (4:0, 3:1, 2:2, 1:3 and 0:4). Kinetine and folcysteine were not effective in increasing the ability of eggplant to compete against purple nutsedge. When no plant growth regulators were used, eggplant was more competitive than nutsedge. As GA3 was applied at a rate of 25 ppm, eggplant competitiveness raised with respect to the control for the 3:1 (+73%), 2:2 (+107%) and 1:3 (+24%) ratios, whereas purple nutsedge RCC values decreased 33, 50 and 50% for 3:1, 2:2 and 1:3 proportions. When 50 ppm of G A3 were sprayed, eggplant aggressivity was enhanced even further with increases of 98, 104 and 55% at the 3:1, 2:2 and 1:3 proportions.

Greenhouse trials were carried out to determine the effect of different ethanol solution concentrations oil the initial growth of'South Bay' lettuce. Lettuce plants in the twotrue leaf stage were dipped in for 2 minutes in a solution containing 0, 5, 10, 15 or 20% ethanol (v/v). Lettuce fresh weight and plant diameter were collected 30 days after treatment. Lettuce plants that received 10 or 15% dipping had the greatest plant diameter and dry weight compared to other treatments, representing about 21.2 and 19.5% increases in fresh weight, respectively. A 22.2% reduction in fresh weight was observed when plants were treated with 20% ethanol solutions. A tertiary relationship characterized the fresh weight response to ethanol rates (y = 109.64 - 0.56x + 0.62x2 - 0.033x3; r2=0.99).

A technological summary on the current weed control practices in soianaceous crops (processing and fresh tomato, peppers, eggplant, potato and tobacco) in the Dominican Republic was compiled based on information supplied by state agencies, private agrochemical companies and growers. According to the data collected, weed management systems integrating chemical and physical (cultivation and hoeing) practices are predominant in processing tomato and potato, whereas cultivation and hoeing are more common in fresh tomato, eggplant, peppers and tobacco. The cost of weed management as a percentage of the total crop production cost averaged 5-10% for potato, 7-15% for peppers, 10-13% for fresh tomato, 10-14% for tobacco, 12% for processing tomato and 15-20% for eggplant. Weed species associated with these crops were abundant, the most troublesome species were: Cyperus rotundus, Parthenium hysterophorus and several grass species in eggplant, processing and fresh tomato; Cyperus rotundus, Sida acuta, Parthenium hysterophorus and grass species in peppers; Cynodon dactylon, Cyperus esculentus and Cyperus rotundus in potato; Amaranthus spp., Chôme viscosa and several grass species in tobacco. The most commonly used herbicides are metribuzin and fluazifop-buthyl in tomatoes, fluazifop-buthyl in peppers and eggplant, linuron, metolachlor, paraquat and ametryn in potato. Herbicide utilization in tobacco is not significant. The number of cultivations and/or hoeings ranged from 1 to 4, depending on the crop species and the early use of herbicides. Yield losses due to weed interference under field conditions is estimated to be 25-35% in eggplant and tobacco, 25-50% in potato, 30-40% in processing and fresh tomato, and 40-50% in peppers.

Container experiments were conducted in the Dominican Republic to determine the influence of gibberellic acid treatment on the competitive ability of tomato, eggplant and bell pepper against the weed Parthenium spp. until crop flowering. The effect of gibberellic acid rates on competitiveness was determined by the changes in relative crowding coefficient values (RCC) in a replacement series of each crop and the weed. Results indicate that gibberellic acid increased crop biomass and thus RCC as rates increased. Bell pepper was the most responsive crop. Since the critical interference period usually occurs before flowering, gibberellic acid treatment at the time of transplanting might prove to be an effective means to improve the competitive ability of this crop against Parthenium spp.

Field experiments were conducted in the Dominican Republic to determine the effect of different rates of imidacloprid on the control of the tomato fruit worm Keiferia lycopersicella. Imidacloprid was applied once at the rates ranging from 25 to 150% of the recommended dosage (0.5 kg/ha), when 80% of the tomato fruits were 2 cm in diameter. Percentage of surviving and dead larvae and percentage of damaged tomato fruits was determined. Results show that Keiferia control (85%) was achieved with 75% of the recommended rate, and that higher rates failed to provide better control.

Area of influence experiments were established on high-organic matter soils to assess the effect of varying common lambsquarters distances on lettuce marketable yield and quality under two phosphorus (P) regimes. Banded (125 Kg/ha) or broadcast (250 Kg/ha) Ρ was applied before lettuce planting. A single 2-week-old common lambsquarters plant was transplanted in the center of each lettuce bed. Lettuce plants were arranged in pairs from the distance to the lambsquarters plant of a given treatment. A weed-free control was also established. Lettuce plants were harvested in pairs at distances of 0, 25, 50, 75, 100 and 125 cm to each side of the lambsquarters plant after season-long interference. Average head fresh weight was collected. Results indicate that lambsquarters severely reduced fresh weight and quality of lettuce plants as spacing decreased. In all cases, banded Ρ diminished the impact of lambsquarters on lettuce. Lettuce pairs grown at 75 cm or more from lambsquarters were apparently not affected by weed interference when Ρ was banded, whereas no effect was present at 100 cm or more when Ρ was broadcast. These data indicates that banding Ρ gives an additional advantage to lettuce within a given distance, reducing the area of influence of lambsquarters.

Trials were conducted under controlled conditions to determine the tolerance of young papaya plants (15 cm tall) to postemergence herbicides. Initial screen trials included paraquat (1.68 Kg ai/Ha), MSMA (2.24 Kg ai/Ha), 2,4-D (4.26 Kg ai/Ha), bromoxynil (0.28 Kg ai/Ha), atrazine (2.24 Kg ai/Ha), cyanazine (1.12 Kg ai/Ha), dimethenamid (1.12 Kg ai/Ha), endothal (0.56 Kg ai/Ha), imazameth (0.067 Kg ai/Ha), imazethapyr (0.028 Kg ai/Ha), acifluorfen (0.28 Kg ai/Ha), lactofen (0.12 Kg ai/Ha), oxyfluorfen (0.03 Kg ai/Ha), and bentazon (1.12 Kg ai/Ha) as well as an untreated control. Atrazine, bentazon, cyanazine, imazethapyr, imazameth and dimethenamid caused, low toxicity at the rates used and dry weights of treated plants were equal to the untreated control. Other herbicides caused severe injuries followed by total death at 10 days after treatment. In the herbicide rate trails, these six screened herbicides were tested along with metribuzin (0.25 Kg ai/Ha), linuron (0.75 Kg ai/Ha) and DCPA (9.00 Kg ai/Ha) at Vi, 1, 2 and 4X rates. Imazameth when applied over-thetop did not significantly reduced papaya weight at the 2X rate when measured 21 days after treatment, whereas 4X rate reduced shoot dry biomass in approximately 40%.

The bacterial wilt of potato was first noticed as a new potential tlireat of economic importance in the highland valley of Tirco in 1993. The disease has been disseminated, apparently by infected tuber-seed and plowing implements, and it is currently reported as an important problem in all lowland and highland potato production areas ofthe Dominican Republic. Chemical control attempts have been unsuccessful. The best results have obtained with an integrated approach of cultural practices, emphasizing the use of certified Pseudomonas-free tuber-seeds, crop rotation without susceptible plant species and avoiding excessive irrigation.

Field trial were conducted in low-phosphorus (P) organic soils to determine the influence of two Ρ fertility regimes and five lambsquarters population densities on lettuce marketable yields. Phosphorus was either banded (125 Kg P/ha) or broadcast (250 Kg P/ha) prior to lettuce planting. Lambsquarters population densities of 0, 2, 4, 8 or 16 plants per 5.4 m2 were allowed to interfere with "South Bay" lettuce within each Ρ regime. Marketable lettuce yield and head number were collected 8 weeks after lettuce emergence. Results indicate that banding Ρ can reduce the negative impact of lambsquarters on lettuce. In all cases, lettuce yields increased approximately 13% when Ρ was banded. At the same time, when Ρ was banded no differences were observed between 2 lambsquarters per 5.4 m* and the weed-free control. However, when Ρ was broadcast, 2, 4, and 8 lambsquarters per 5.4 m2 were enough to reduce lettuce marketable yield in about 33, 50 and 65%, respectively. No significant differences were observed between 8 and 16 lambsquarters per 5.4 m2 when Ρ was broadcast. Maximum lettuce yield reductions occurred at either 4, 8, or 16 lambsquarters per 5.4 mJ when Ρ was banded, corresponding to approximately 34%.

Field experiments were conducted in the Dominican Republic to determine the effects of nitrogen (N) supply and purple nutsedge population densities on the yield of radish. An additive series of 0, 50, 100, 150 and 200 purple nutsedge plants per m2 was established the same day radish was sown. Nitrogen rates were 100 and 200 Kg/ha. Marketable radish yield losses, and purple nutsedge shoot dry weight and height were determined 30 days after seeding the crop. Nutsedge densities and Ν rates independently affected radish root yield, but no significant Ν by density interaction was detected. Root yield loss reached 100% at nutsedge densities of 75 and 125 plants per m2 at 200 and 100 Kg N/ha, respectively. Purple nutsedge produced larger shoot biomass as Ν increased from 100 to 200 Kg/ha. No significant differences were observed for purple nutsedge height, regardless of the Ν rate utilized. Results show that as Ν increased the negative effect of the weed on the crop was enhanced.

Tolerance trials were carried out under greenhouse conditions to determine the tolerance of cilantroto selected postemergence herbicides. Herbicides used were paraquat (1.68 Kg active ingredient/Ha), MSMA (2.24 Kg ai/Ha), 2,4-D (4.26 Kg ai/Ha), bromoxynil (0.28 Kg ai/Ha), atrazine (2.24 Kg ai/Ha), cyanazine (1.12 Kg ai/Ha), metribuzin (0.25 Kg ai/Ha) dimethenamid (1.12 Kg ai/Ha), endothal (0.56 Kg ai/Ha), linuron (0.75 Kg ai/Ha), imazameth (0.067 Kg ai/Ha), imazethapyr (0.028 Kg ai/Ha), acifluorfen (0.28 Kg ai/Ha), lactofen (0.12 Kg ai/Ha), oxyfluorfen (0.03 Kg ai/Ha), and bentazon (1.12 Kg ai/Ha) as well as the untreated control. Herbicides were sprayed when plants reached the two-true leaf stage (approximately 20 days after emergence). No adjuvant was used in herbicide preparations. Linuron, bentazon, oxyfluorfen, acifluorfen, imazethapyr and metribuzin seemed to be have some potential for weed control in cilantro. Other herbicides caused severe phytotoxicity on cilantro leaves.

Field experiments were conducted in Gainesville, Florida, to determine the response of 'White Stem' C h i n e s e cabbage to foliar applications of the biostimulant folcysteine. Rates of 100, 300, 500 and 700 ppm folcysteine were applied once (7 days after transplanting) or twice (7 and 21 days after, transplanting). Plant fresh biomass was determined 50 days after transplanting. Results show that 'White Stem' pok-choi was responsive to folcysteine. When the biostimulant was applied once, overall growth was enhanced as rates increased, reaching maximum yield at the rate of 500 ppm as determined by a quadratic relationship (y = 21.8 + 0.20x - 0.0002x2; r2 = 0.97). Yield decreased at the rate of 700 ppm. When folcysteine was applied twice, the highest yield was obtained at 100 ppm per spray, with higher rates failing to increase yields above control levels. A linearplateau equation characterized this relationship (y = 23.8 + 0.27x, if χ < 100; y = 23.8, if χ > 100)

Experiments were conducted under controlled conditions to determine the effect of different ethanol concentrations on the initial growth of'Camelot' bell pepper. Plants in the two-true leaf stage were submersed for 2 minutes in either 0, 5, 10, 15 or 20% ethanol solution (v/v). Plant height, leaf area per plant, number of floral buds per plant and leaf and stem dry weight per plant were collected 40 days after treatment. Bell pepper plants had the highest values for all variables under study when solutions containing 10% ethanol were applied. In most cases, 20% solutions reduced variables studied at or below control levels.

We describe two sisters who each presented in infancy with acute, severe, generalised weakness and are-flexia in association with an intercurrent infection. The clinical picture resembled acute polyneuritis, but EMG findings and the later clinical features were consistent with a diagnosis of spinal muscular atrophy. Although symptoms in SMA may be exacerbated by infection, immunisation or trauma, this unusual presentation of the condition in siblings suggests that this may constitute a genetically distinct subgroup of the disorder.