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Rick A. Boydston, Harold P. Collins and Steven F. Vaughn

). However, poor efficacy or high cost of many natural products have limited their use. Corn gluten meal is a byproduct from corn wet-milling and has been used to control weeds in turf and other crops ( Liu et al., 1994 ; Liu and Christians, 1997 ; McDade

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Lavesta C. Hand, Wheeler G. Foshee III, Tyler A. Monday, Daniel E. Wells and Dennis P. Delaney

physically inhibit it from reaching the soil to control emerging weeds ( Locke and Bryson, 1997 ). Teasdale et al. (2003) reported that hairy vetch ( Vicia villosa ) increased decomposition rates and initial soil solution of metolachlor. This led to reduced

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Dean McGraw and Bruce Bostian

Effects of herbicides and weeds were demonstrated by exposing `Excel' sweetpotatoes to a randomized complete block design of 3 replications of various treatments ranging from phytotoxity to no weed control in 1991 & 1992. Plots were either left unweeded, hoed clean or treated with herbicides (sethoxydim, clomazone, metolachlor, imazethapyr) or selective hand weeded to remove broadleaf weeds. Hand weeded treatments were hoed twice. After 120 days weeds remaining in each plot were cut at ground level, dried and weighed. At 125 days the plots were harvested. The roots were cured, graded and weighed. Weed dry weight ranged from zero to nearly 6.5 cwt/A. Weed dry weight as a % of total marketable sweetpotatoes ranged from zero to 34.5% in 1991 and zero to 19.8% in 1992. Competition from grasses reduced sweetpotato yield more than broadleaf weeds. Total marketable sweetpotato yields ranged from zero to 426 cwt/A in 1991 and from 210 cwt/A to 289 cwt/A in 1992.

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William J. Sciarappa* and Gary C. Pavllis

Weeds are especially problematic in highbush blueberry which has a long establishment period, shallow-fibrous roots, and poor competitive ability in obtaining water, nutrients and sunlight. Commercial approaches in certified organic blueberry fields compared horticultural management methods in two New Jersey sites. The trials utilized both new and established blueberry blocks having trickle or overhead irrigation. Commercial methods investigated included rotary cultivation, mowing, propane flaming, cover crops, landscape fabric, and various mulches. Mulch comparisons included pine bark mulch, hardwood mulch, coffee grinds, cocoa grinds, municipal leaf mulch, and composted tea leaves. 3' × 12' plots were replicated 4 times in 4 adjoining rows. Applications of 3-4 inches of these mulches within the crop row to a new planting of Duke highbush blueberry have provided a combined weed control level of ca. 95% without landscape fabric and ≈98% with landscape fabric during 2003. Walkway weed suppression in new plantings was achieved with the establishment of two types of fine leafed turf fescues and monthly mowings. Bare ground percentage decreased from 80% to <2% within one year's time as these fine fescues gradually out-competed annual weeds for space. These fescue cover crops increased ground coverage from 8% to >95% over the seven month growing season. Such varieties were selected because they have good germination, require little water, use limited nitrogen and can squeeze out weeds through allelopathy. Applied research studies indicate that several suitable methods can be utilized for effective weed management in organic highbush blueberry production systems.

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Joseph N. Aguyoh, John B. Masiunas and Catherine Eastman

Integrated weed management strategies maintain sub-threshold levels of weeds. The remaining weeds may impact the feeding and habitation patterns of both potato leafhoppers and bean leaf beetles in a snap bean agroecosystem. The objective of our study was to determine the effect of interference between snap beans (Phaseolus vulgaris L.) and either redroot pigweed (Amaranthus retroflexus L.) or large crabgrass (Digitaria sanguinalis L.) on populations of potato leafhopper [Empoasca fabae (Harris)] and bean leaf beetle [Cerotoma trifurcata (Forster)]. Plots were seeded with redroot pigweed or large crabgrass at either the same time as snap bean planting (early) or when snap bean had one trifoliate leaf open (late). The weed density averaged two plants per meter of row. Bean leaf beetle populations, snap bean pod damage, and leaf defoliation were lower in weed-free plots compared to those with either early emerging pigweed or crabgrass. Leafhopper nymphs and adults were 31% to 34% less in plots with crabgrass emerging with snap beans compared to those in weed-free snap bean plots. Thus, the effect of sub-threshold densities of pigweed and crabgrass on insect pests in snap bean varied depending on the species and should be considered when deciding to integrate weed management approaches.

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John C. Stier, Eric J. Koeritz and Mark Garrison

.6%), MCPP (2-methyl 1–4 chlorophenoxy propionic acid, 8.2%), and triclopyr (3,6-dichloro-o-anisic acid, 2.8%) on 21 June 2005 and 29 June 2006 to control broadleaf weeds. Plots were fertilized with nitrogen at 4.9 g·m −2 using a 25N–0.9P–3.3K fertilizer

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S.D. Sharma and M. Singh

vegetation management in citrus groves and is the most commonly used herbicide for effective postemergence (POST) weed management in the Florida ( Jackson and Davies, 1999 ). Although glyphosate is a broad-spectrum herbicide, not all weeds are equally

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Lyn A. Gettys and Michael A. Schnelle

Conventional wisdom suggests that only introduced species can be invasive and that indigenous species cannot be classified as “weeds” because they belong in their native range. Therefore, most weed ecology and management research is focused on non

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John B. Workman, Patrick E. McCullough, F. Clint Waltz, James T. Brosnan and Gerald M. Henry

Synthetic auxins are popular herbicides for selective, postemergence broadleaf weed control in turfgrass management ( Struckmeyer, 1951 ; Watson, 1950 ). Herbicides in this class of chemistry control susceptible weeds by disrupting hormonal balance

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Erin Schroll, John G. Lambrinos and David Sandrock

abundance. Test beds were kept weed-free (free of any non-planted species) until the start of the irrigation trials (25 June 2008). Once per month throughout the irrigation experiment (25 July, 25 Aug., and 25 Sept.), all shoots and roots of emerged weeds