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  • Author or Editor: Robert McNiel x
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Abstract

Nodules from 13 woody plant species were analyzed by an acetylene reduction assay to determine their nitrogen fixation activity. Acetylene reduction activity was found with nodules from Alnus glutinosa (L.) Gaertn., Caragana arborescens Lam., Elaeagnus angusti/olia L., E. umbellata Thunb., Hippophae rhamnoides L., Myrica pensylvanica Lois, Robinia fertilis Ashe., R. hispida L., R. pseudoacacia L., Shepherdia argentea Nutt., and S. canadensis Nutt. In addition, nodules from A. glutinosa were found to reduce acetylene for at least 9 hours after having been excised from the plant No active nodules were found on Comptonia peregrina (L.) Coult. or Cercis canadensis L.

Open Access

Twenty-six purple- or green-leaved cultivars representing 12 species of woody landscape plants were evaluated in the field for defoliation by Japanese beetles (Popillia japonica Newman) over three growing seasons. We further evaluated the hypothesis that, within closely-related plants, purple cultivars generally are preferred over green ones by comparing beetles' consumption of foliage in laboratory choice tests and their orientation to painted silk tree models baited with Japanese beetle lures. Cultivars of Prunus cerasifera Ehrh. and hybrids of that species [e.g., Prunus ×cistena (Hansen) Koehne, Prunus ×blireiana André] were more heavily damaged than nearly all other plants tested. Among maples, Acer palmatum Thunb. `Bloodgood' and A. platanoides L. `Deborah' and `Fairview' were especially susceptible. None of the cultivars of Berberis thunbergii DC, Cercis canadensis L., Cotinus coggygria Scop., or Fagus sylvatica L. were heavily damaged, regardless of foliage color. In the choice tests, purple Norway maples were preferred over green ones in three of four comparisons, but preference varied within the other plant genera. In fact, more beetles oriented to green-leaved tree models than to purple ones. Our results indicate that within a genus, purple-leaved plants do not necessarily sustain more damage than green-leaved ones. Widespread use of certain purple-leaved cultivars of generally susceptible plant species probably contributes to the perception that purpleleaved plants, overall, are preferred. Purple-leaved cultivars of redbud, European beech, smoketree, and barberry, or the purple-leaved Prunus virginiana L. `Canada Red' or Malus ×hybrida Lemoine `Jomarie' may be suitable substitutes for more susceptible purple-leaved plants in landscapes where Japanese beetles are a concern.

Free access

Sulfentrazone is a promising new herbicide now under evaluation for use in agronomic and ornamental cropping systems. Sulfentrazone selectively controls yellow nutsedge, morningglories, and other annual grasses and broadleaf weeds. Research was conducted to evaluate the efficacy of sulfentrazone in combination with other labeled products for preemergence weed control in nursery crops. Treatments included sulfentrazone at 0.56 and 1.12 kg a.i./ha and sulfentrazone at 0.37 kg a.i./ha in combination with the following; dithiopyr at 0.37 kg, oxyfluorfen at 0.56 kg, metolachlor at 3.36 kg, isoxaben at 0.56 kg, norfluorazon at 2.64 kg, and isoxaben plus oryzalin at 2.24 kg a.i./ha. Combinations of sulfentrazone with isoxaben or metolachlor provided superior control of morningglory spp., honeyvine milkweed, Carolina horsenettle, and yellow nutsedge. Sulfentrazone plus oxyfluorfen or isoxaben plus oryzalin also provided good control. Poorest overall control was obtained with sulfentrazone plus dithiopyr. Viburnum and deciduous holly were slightly injured 4 WAT with sulfentrazone plus metolachlor. Sulfentrazone plus dithiopyr treatments resulted in serious injury to burning bush 4 WAT and slight injury at 8 WAT.

Free access

The nursery industry currently has few options for effective season-long weed control, because few soil persistent herbicides are registered for use in ornamentals. An herbicide that provides season-long weed control with minimal injury to ornamentals would be extremely beneficial because it would enable the nurseryman to produce high-quality ornamentals with minimal weed interference Sulfentrazone (F6285), a newly developed herbicide from the FMC Corp., has shown promising results for weed control in field trials with ornamentals. Additional, trials are needed to further evaluate sulfentrazone in hopes that it may be registered for use in ornamentals in the future. Our objectives are 1) to increase long-term weed management in ornamentals, including woody species and groundcover; 2) to evaluate rate structures of sulfentrazone and combinations, including preemergence and postemergence herbicides; 3) to evaluate sulfentrazone selectivity in weed species and in ornamentals; 4) to evaluate sulfentrazone mode of action in weed species; and 5) to measure the soil activity of sulfentrazone. To achieve the first three objectives, a randomized complete block design will be used to evaluate 10 woody species and 17 herbicide combinations. The response variables will be weed control and phytotoxicity ratings taken at 0, 4, 8, and 12 weeks after treatment. The results of this study will be used in ongoing research trials in an attempt to register sulfentrazone (F6285) for use in ornamentals.

Free access

The objective of this project is to estimate establishment and operating costs for garden centers at two levels of sales and to specify the general set of financial, marketing and business principles that should be available to the owner/manager of a garden center.

After surveying 25 garden centers across the United States, two models were derived. A large garden center with annual sales of $1,000,000 is described. A smaller garden center with annual sales of $350,000 is described. Capital budgets, including investment and operations costs for each firm have been developed.

Each firm is evaluated based on standard business indicators. A merchandising program composed of layout, pricing, advertising, cost structure and diversification is outlined.

Free access