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Charles H. Gilliam, Donna C. Fare, and Gary J. Keever

Little information is available on herbicide movement in soilless container media and subsequent movement in container leachate and container bed runoff. The objective of this study was to evaluate oxyfluorfen movement in irrigation water following application to container grown nursery crops in a commercial nursery. Oxyfluorfen levels in the container bed runoff were 9 to 27 times higher than those in container leachate during the 3 irrigations following herbicide application. Maximum oxyfluorfen level in the container leachate was 8.3 ppb following the first irrigation but declined to 2.0 ppb by the 12th irrigation. The oxyfluorfen level was still about 2.0 ppb following the 75th irrigation. Oxyfluorfen in the container bed runoff peaked at 99 ppb following the 3rd irrigation before declining to 67 ppb following the 6th irrigation.

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Glenn B. Fain, Charles H. Gilliam, and Gary J. Keever

Hardy ferns are widely grown for use in the landscape. Studies were conducted to evaluate the tolerance of variegated leatherleaf fern (Arachniodes simplicor `Variegata'), tassel fern (Polystichum polyblepharum), autumn fern (Dryopteris erythrosora), holly fern (Cyrtomium falcatum `Rochfordii'), and southern shield fern (Dryopteris ludoviciana), to applications of selected preemergence applied herbicides. Liquid applied herbicides were pendamethalin (LPM) at 3.36 or 6.73 kg·ha–1, prodiamine (LPD) at 1.12 or 2.24 kg·ha–1, isoxaben (LIB) at 1.12 or 2.24 kg·ha–1, and the combination of prodiamine plus isoxaben (LPI) at 1.12 plus 1.12 kg·ha–1. Granular applied herbicides were pendamethalin (GPM) at 3.36 or 6.73 kg·ha–1, prodiamine (GPD)1.12 or 2.24 kg·ha–1, oxadiazon plus prodiamine (GOP) at 1.12 + 0.22 or 2.24 + 0.44 kg·ha–1, oxyfuorfen plus oryzalin (GOO) at 2.24 + 1.12 or 4.48 + 2.24 kg·ha–1, trifluralin plus isoxaben (GTI) at 2.24 + 0.56 or 4.48 + 1.12 kg·ha–1, oxadiazon (GO) at 4.48 or 8.97 kg·ha–1, and oxadiazon plus pendamethalin (GOPD) at 2.24 + 1.4 or 4.48 + 2.8 kg·ha–1. The greatest reduction in growth of autumn fern was observed with GOPD, GO, and GOP; all three containing oxadiazon as an active ingredient. Reductions in holly fern growth were most severe when plants were treated with GTI resulting in a 42% and 54% decrease in frond length and frond number, respectively. There were also reductions in number of fronds when treated with LPM, GPM, GOP, GOO, and GOPD. There were no reductions in frond numbers on tassel fern with any herbicides tested. However, there were reductions in frond length from 6 of the 10 herbicides evaluated. The most sensitive fern to herbicides evaluated in 2004 was leatherleaf with reductions in frond length and number of fronds with 6 of the 10 herbicides tested. While all herbicides tested on southern shield fern appeared to be safe, especially in the 2004 study, tassel fern and holly fern appear to be more sensitive. GPD proved to be a safe herbicide for all species tested in both 2004 and 2005. In 2005 all plants from all treatments were considered marketable by the end of the study. However there was significant visual injury observed on the holly fern treated with LIB at 60 and 90 days after treatment which might reduce their early marketability.

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Gary J. Keever, William D. Goff, and Mark S. West

Pecan [Carya illinoensis (Wangenh.) C. Koch] trees were grown in containers in a pine bark and sand medium amended with O, 3.0, 5.9, 8.9, or 11.9 kg dolomitic limestone/m. Mouse-ear symptom expression, characterized by small, rounded, cupped, and slightly wrinkled leaflets, increased linearly as dolomitic lime rate increased. Plant growth was best at 3.0 kg dolomitic lime/m, which resulted in a growth medium pH of 4.3.

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Bridget K. Behe, C. Fred Deneke, and Gary J. Keever

Tissue-cultured plugs of Nandina domestica Thunb. `Hat-hour Dwarf' and `San Gabriel' were grown in 1.5-liter pots under 30%, 47%, or 62% shade. After 20 weeks, plants were moved to a simulated consumer environment (SCE) maintained at 21C, ≈60% relative humidity, and a 12-hour photoperiod with an irradiance of 7 μmol·m -2·s-1. Final quality ratings (after 35 weeks in the SCE) for both cultivars were good, but the plant quality of `San Gabriel' declined more quickly than that of `Harbour Dwarf'. Final quality rating of `Harbour Dwarf' grown under the highest percentage of shade was higher than that of plants grown under 30% or 47% shade; production shade percentages had no influence on the final quality rating of `San Gabriel'. Plants (of both cultivars) grown in 0.6-liter (11-cm-diameter) pots were test-marketed through six supermarket floral departments and captured 16% of total 10- to 11-cm-size foliage plant sales. Sixty percent of consumers indicated the plant's “newness” as the primary consideration for its purchase. These two N. domestica cultivars could be marketed successfully as interior foliage plants.

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Donna C. Fare, Charles H. Gilliam, and Gary J. Keever

Efficient usage of current water supplies is of great concern to container-nursery producers. Improving water management first requires knowledge of current commercial container production practices. In this study, irrigation distribution from overhead sprinklers was monitored at container nurseries to determine the distribution and the amount of irrigation applied during a typical irrigation cycle. Several nurseries surveyed had poorly designed irrigation systems; subsequently, irrigation distribution varied widely at sampling dates and within the growing-container block. Uniform distribution was achieved at some nurseries, but required careful monitoring of the irrigation system. Future water restrictions may force nurseries to improve water usage by changing irrigation delivery methods to minimize water use, resulting in reduced surface runoff and effluent from container nurseries.

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Glenn B. Fain, Charles H. Gilliam, and Gary J. Keever

Hardy ferns are widely grown for use in the landscape. The 1998 National Agricultural Statistics Services census of horticulture reported production of hardy/garden ferns at 3,107,000 containers from over 1200 nurseries. There is little research on herbicide use in hardy ferns, and herbicides that are labeled for container production are not labeled for use on hardy ferns. Studies were conducted to evaluate the tolerance of variegated east indian holly fern (Arachniodes simplicior `Variegata'), tassel fern (Polystichum polyblepharum), autumn fern (Dryopteris erythrosora), rochford's japanese holly fern (Cyrtomium falcatum `Rochfordianum'), and southern wood fern (Dryopteris ludoviciana), to applications of selected preemergence applied herbicides. Herbicides evaluated included selected granular or liquid applied preemergence herbicides. Spray-applied herbicides were pendimethalin at 3.0 or 6.0 lb/acre, prodiamine at 1.0 or 2.0 lb/acre, isoxaben at 1.0 or 2.0 lb/acre, and prodiamine + isoxaben at 1.0 + 1.0 lb/acre. Granular-applied herbicides were pendimethalin at 3.0 or 6.0 lb/acre, prodiamine at 1.0 or 2.0 lb/acre, oxadiazon + prodiamine at 1.0 + 0.2 or 2.0 + 0.4 lb/acre, oxyfluorfen + oryzalin at 2.0 + 1.0 or 4.0 + 2.0 lb/acre, trifluralin + isoxaben at 2.0 + 0.5 or 4.0 + 1.0 lb/acre, oxadiazon at 4.0 or 8.0 lb/acre, and oxadiazon + pendimethalin at 2.0 + 1.25 or 4.0 + 2.5 lb/acre. The greatest reduction in growth of autumn fern was observed with the high rates of oxadiazon, oxadiazon + pendimethalin, and oxadiazon + prodiamine. Reductions in rochford's japanese holly fern growth were most severe when plants were treated with the high rate of trifluralin + isoxaben resulting in a 66% and 72% decrease in frond length and frond number, respectively. There were also reductions in frond length and number of fronds when treated with the high rate of oxadiazon + pendimethalin. There were no reductions in frond numbers on tassel fern with any herbicides tested. However, there were reductions in frond length from four of the 10 herbicides evaluated. The most sensitive fern to herbicides evaluated in 2004 was variegated east indian holly fern with reductions in frond length and number of fronds with four of the 10 herbicides tested. Southern wood fern appeared to be quite tolerant of the herbicides tested with the exception of the high rate of oxadiazon. Granular prodiamine proved to be a safe herbicide for all species tested in both 2004 and 2005. In 2005 all plants from all treatments were considered marketable by the end of the study. The durations of both studies were over 120 days giving adequate time for any visual injury to be masked by new growth. However, there was significant visual injury observed on the rochford's japanese holly fern treated with isoxaben at 60 and 90 days after treatment, which might reduce their early marketability.

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Gary J. Keever, WJ. Foster, J.W. Olive, and Mark S. West

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James M. Garner, Gary J. Keever, D. Joseph Eakes, and J. Raymond Kessler

A study conducted in 1995 and repeated in 1996 determined the effects of repeated BA applications and subsequent repeated removals on yields of offsets in Hosta Tratt. (Funkia K. Spreng; Niobe Salisb.) stock plants. Two hosta cultivars, `Francee' and `Francis Williams', received zero, one, two, three, or four foliar applications of benzyladenine (BA) at 3000 mg·L-1. Plants receiving multiple applications were retreated at 30-day intervals following offset removal from all plants. A single BA application stimulated offset formation in both cultivars in both years, but repeated applications were necessary for a continued response following offset removal. Total offset yield increased linearly as the number of BA applications increased. At 120 days after the first treatment in 1995, `Francee' plants receiving four applications had produced an average of 22 offsets, and `Francis Williams' plants 18 offsets, whereas control plants produced 9.8 and 0 offsets, respectively. Similar data for 1996 were 31.2 offsets for `Francee' and 22.4 offsets for `Francis Williams,' whereas control plants produced 6.8 and 2.6 offsets, respectively. Offset stage of development, as indicated by leaf number, and growth index generally were not affected by BA treatment. No phytotoxicity was observed, and plant appearance was enhanced due to the outgrowth of BA-stimulated lateral buds. Chemical name used: N-(phenylmethyl)-1H-purin-6-amine (benzyladenine, BA).

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James M. Garner, Gary J. Keever, D. Joseph Eakes, and J. Raymond Kessler

A foliar spray of 0, 1250, 2500, or 3750 mg benzyladenine (BA)/L was applied to 10 Hosta Tratt. (Funkia K. Spreng; Niobe Salisb.) cultivars. Response to BA treatment was cultivar dependent, with BA promoting offset formation in half of the cultivars. Compared to the control, increase in offsets produced by cultivars treated with 3750 mg BA/L ranged from 116% in `Francee' to 3500% in `Francis Williams' at 30 days after treatment (DAT) and from 150% in `Royal Standard' to 2250% in `Francis Williams' at 60 DAT. Offset stage of development, as indicated by the number of unfurled leaves, was also cultivar- and BA-dependent. All cultivars treated with 3750 mg BA/L had an average of three or more unfurled leaves at 60 DAT, while among control plants, 40% of cultivars averaged fewer than three unfurled leaves. No phytotoxic symptoms were noted in any cultivar, and plant size was either increased or not affected by BA treatment. Chemical name used: N-(phenylmethyl)-1H-purin-6-amine (benzyladenine; BA).