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- Author or Editor: Steve M. Olson x
- HortScience x
Tomato (Lycopersicon esculentum Mill.) was grown with drip irrigation on an Arredondo fine sand and on an Orangeburg fine sandy loam to evaluate the effect of N and K time of application on petiole sap, leaf-N and -K concentrations, fruit yield, and to determine N and K sufficiency ranges in leaf tissue. On the sandy soil, N—K at 196-112 kg·ha-1 were applied 0%, 40%, or 100% preplant with the remainder applied in 6 or 12 equal or in variable applications in 12 weeks. With the variable application rate, most nutrients were applied between weeks 5 and 10 after transplanting. On the sandy loam soil that tested high in K, only N (196 kg·ha-1) was applied as above. Petiole sap K concentration declined during the season, but was not greatly affected by treatment. Petiole NO3-N concentrations decreased during the season from 1100 to 200 mg·L-1, and the decrease was greater with preplant N treatments. On the sandy soil, marketable fruit yields were lowest with 100% preplant, intermediate with 100% drip applied (no preplant N), and highest with 40% preplant and 60% drip applied. With 100% drip applied, yields were higher with 12 even applications than with either six even weekly applications or with 12 variable N and K applications. With 40% preplant, timing of application had little effect on yield. On the sandy loam soil in 1993, yields were highest with 100% preplant, intermediate with 40% preplant and 60% drip applied, and lowest with all N drip applied. In 1994 when excessive rains occurred, yields were similar with all preplant and with split N applications. Petiole N concentration was correlated with tomato yield, especially at 10 weeks after transplanting. The best correlation between sap-N and total yields occurred between 4 and 6 weeks at Gainesville and between 4 and 10 weeks at Quincy.
Abstract
‘Horizon’, a small shoot-mass tomato (Lycopersicon esculentum Mill) cultivar, and ‘Sunny’, a large shoot-mass cultivar were planted at 30.5-, 61-, and 91-cm within-row spacings at five locations in Florida during Spring 1985 to determine if yields differed between these cultivars and among plant densities. Marketable weight and number of fruit per plant, mean fruit size (g/fruit), and shoot weight increased linearly with an increase in within-row spacing. Marketable weight of fruit/ha decreased linearly with wider within-row spacings. Responses of both cultivars to within-row spacing were similar for each measured trait, except for marketable fruit number per plant. A larger increase in marketable number of fruit per plant occurred between 61- and 91-cm within-row spacings for ‘Sunny’ than for ‘Horizon’. Fruit : shoot ratio (w/w) was not influenced by within-row spacings or cultivars. Each measure variable differed among locations. These results suggest that ‘Sunny’, with a larger inherent shoot growth, sufficiently compensated for smaller shoot growth when grown at higher plant densities to maintain marketable fruit yields comparable to ‘Horizon’.
Studies were conducted at three locations in Florida to evaluate the effects of kasugamycin alone, in alternation, or as a tank-mix partner with copper bactericides and other fungicides against bacterial spot of tomato. In greenhouse trials, kasugamycin, formulated as Kasumin® 2L, reduced bacterial spot severity by up to 37.5% compared with a non-treated control. Little advantage in disease control was observed by mixing kasugamycin with other fungicides. Kasugamycin was assessed in six field trials. In the four field trials that tested kasugamycin alone, it was as effective as the standard copper + mancozeb treatment for the control of bacterial spot. In four trials, no benefit was observed in applying kasugamycin as a mixture with copper + mancozeb, and only one of three trials did alternating kasugamycin with copper + mancozeb improve bacterial spot control over either the copper + mancozeb standard or kasugamycin alone. Although kasugamycin was effective for the control of bacterial spot in greenhouse and field trials, rapid development of resistance in field populations of X. perforans may shorten the effective use of this antibiotic.