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effective, economical, and practical measure for controlling FOM ( Martyn and Miller, 1996 ). In the event that a resistant cultivar is not available in a given area, the use of other cucurbit species not susceptible to FOM as rootstocks for grafting

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Zucchini yellow mosaic virus Theor. Appl. Genet. 120 191 200 Provvidenti, R. Gonsalves, D. Humaydan, H.S. 1984 Occurrence of Zucchini yellow mosaic virus in cucurbits from Connecticut, New York, Florida, and California Plant Dis. 68 443 446 Provvidenti, R

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Current cucurbit production systems in the United States often rely on tillage and plastic film mulches to create favorable growing conditions of warm soils and minimal weed pressure around plants; however, there are environmental concerns about the

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alternative rootstocks available would help develop long-term strategies for pest and disease control, particularly for introduction of grafting into open-field tomato production. Grafted cucurbit seedling production and use. Several commercial trials

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Brushing (40 strokes per 1.5 minutes, twice daily) or moisture stress conditioning (MSC) (daily nonlethal dry-down cycles) reduced seedling growth of two cucumber (Cucumis sativus L.) cultivars in 1991 and three squash (Cucurbita pepo L.) cultivars in 1991 and 1992. In both years, watermelon [Citrullus lanatus Thunb. (Matsum. & Nakai)] cultivars varied in responsiveness to brushing; brushing reduced stem length 0% to 44% over four cultivars in 1992. MSC reduced growth of all cultivars. Brushing increased the rate of water loss from detached leaves of cucumber, squash, and watermelon, whereas MSC decreased water loss from leaves of cucumber and squash. In 1991, under well-watered posttransplant conditions, MSC increased the mean relative growth rate (RGR) of cucumber and watermelon transplants in the greenhouse. Brushing increased the RGR of watermelon transplants. In 1992, MSC increased the RGR of squash and watermelon transplants grown under posttransplant drought-stressed conditions, while brushing had no effect. Both conditioning treatments controlled plant growth in the greenhouse without diminishing subsequent plant performance.

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Abstract

The rate and total germination of cucumber (Cucumis sativus L.) seeds incubated at 12°C was markedly increased by acetone infusion with fusicoccin (FC). Gibberellic acid (GA4/7) was less effective than FC but more effective than GA3 or (2-chloroethyl)phosphoric acid (ethe-phon) in promoting rapid germination. Infusion of GA4/7 alone or in combination with kinetin and/or ethephon into muskmelon (Cucumis melo L.) seeds increased total germination at 16°C The growth regulators were generally not effective in promoting low temperature germination of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) seeds.

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Field studies were conducted in 1993, 1994, and 1996 to determine the tolerance of several cultivars of zucchini and yellow crookneck squash (Cucurbita pepo L.) to various rates and methods of application of clomazone, ethalfluralin, and pendimethalin. Applying herbicides preplant soil incorporated (PPI), preemergence (PRE), at seedling emergence (SE), or early postemergence (EPOT) resulted in plant injury that varied from 0% to 98%. Ethalfluralin and pendimethalin (PPI) at 1.12 kg·ha–1 a.i. resulted in the greatest stand and yield reductions across all cultivars. Fruit number and weight declined for all cultivars in 1993 and 1994 as the amount of pendimethalin applied PRE was increased. Zucchini (`Senator') fruit size was significantly reduced for the first three harvests in 1993 by PRE application of pendimethalin or PPI application of ethalfluralin, at all rates. Yellow squash (`Dixie') fruit size was unaffected by herbicide treatment for any harvests during 1993 or 1996. Yellow and zucchini squash yield, fruit number, and average fruit weight were equal to, or greater than, those of the untreated control for PRE clomazone using either the emulsifiable concentrate formulation (EC) during 1993, 1994, and 1996 or the microencapsulated formulation (ME) during 1996. Foliar bleaching and stunting by clomazone was evident in early-season visual observations and ratings, but the effect was transient. Foliar bleaching by clomazone PPI (1.12 kg·ha–1 a.i.) was more evident in `Senator' zucchini, and yield was significantly reduced in 1993. These effects of clomazone PPI were not evident in 1994 for either `Elite' or `Senator' zucchini squash. Chemical names used: 2-[(2-chlorophenyl)methyl]-4, 4-dimethyl-3-isoxazolidinone (clomazone); N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine (ethalfluralin); N-(1-ethylopropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin).

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Field studies were conducted in 1993, 1994, and 1995 to determine tolerance of seeded and transplanted watermelon [Citrullus lanatus (Thunb.) Matsum and Nak.] to clomazone, ethalfluralin, and pendimethalin using method of stand establishment (directseeded vs. transplanted) and time of herbicide application [preplant soil incorporated (PPI), preplant to the surface (PP), or postplant to the surface (POP)] as variables. Yield and average fruit weight in plots with clomazone were equal to or greater than those in control plots for the 3-year study regardless of method of application. Bleaching and stunting were evident with clomazone in early-season ratings, but injury was transient and did not affect quality or yield. Of the three herbicides, ethalfluralin PPI resulted in the greatest injury, stand reduction, and yield reduction of the three herbicides. Pendimethalin (PPI, PP, or POP) reduced yield of direct-seeded but not of transplanted watermelon. Chemical names used: 2-[(-2-chlorophenyl)methyl]-4, 4-dimethyl-3-isoxazolidinone (clomazone); N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine (ethalfluralin); N-(1-ethylopropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin).

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Abstract

This study evaluates light quality and photoperiodic effects on vegetative growth on Cucurbita maxima Duch. In a growth chamber with fluorescent and incandescent lighting the quality of light prior to the dark period, rather than photoperiod, significantly affected internode elongation, and end-of-day red (R) and far-red (FR) treatments demonstrated phytochrome involvement. Internode elongation occurred primarily during the dark period. FR treatments at the beginning of the dark period were most promotive, but FR up to 12 hour into a 16 hour dark period promoted internode elongation significantly. Changes in the ratio of R to FR light at sunset are probably not of sufficient duration and intensity to elicit an end-of-day growth response. In the field, changes in light quality at sunset did not alter the growth habit of the bush or bush-vine phenotypes.

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