Efficacy Of Pre-emergence Herbicides Research Articles

Preemergence Herbicide Efficacy Under Athletic Field Traffic

Preemergence Herbicide Efficacy Under Athletic Field Traffic

Efficacy of preemergence herbicides on three annual grass weeds in different soils

Pot experiments evaluated the efficacy of several preemergence herbicides on three annual grasses that are major problem weeds in most maize growing regions Herbicides evaluated included alachlor metolachlor dimethenamid two formulations of acetochlor and proprietary mixes of acetochlor with atrazine or metribuzin Pots were filled with soil collected from the top 10 cm of seven maize (Zea mays) fields with different cropping histories and seeded with test grasses Herbicides were applied immediately after sowing with a precision glasshouse sprayer Additional seeds were sown at 2weekly intervals for 8 weeks Seedlings were counted 2 weeks after each planting Metolachlor was most effective in controlling summer grass (Digitaria sanguinalis) and rough bristle grass (Setaria verticillata) All herbicides were less effective against the large seeded broom corn millet (Panicum miliaceum) than the other grasses All the herbicides except metolachlor were less effective in soils with a long history of maize growing

Preemergence Herbicide Efficacy and Phytotoxicity in Grain Sorghum

Field studies conducted from 2005 to 2007 in Kansas compared the effects of KIH-485 and flufenacet to acetochlor and s-metolachlor applied PRE in grain sorghum. All treatments were combined with 1.12 kg/ha of atrazine for broadleaf weed control. KIH-485 and flufenacet, each at one time (1×) and two times (2×) the labeled rates, controlled large crabgrass 55 to 76% in 2005 and 94% or more in 2006 and 2007. In 2005, all herbicides controlled shattercane less than 20%, and only KIH-485 at the 2× rate controlled shattercane more than 70% in 2006 and 2007. Averaged over herbicides, green foxtail was controlled 98% in 2005, 77% in 2006, and 79% in 2007. Most herbicides controlled foxtail 86% or more when averaged over experiments, however, s-metolachlor at 1×, flufenacet at either rate, or atrazine alone did not. Sorghum was not stunted with KIH-485 or flufenacet in two of seven experiments. However, sorghum growth was reduced 23 to 54% with the 2× rates of KIH-485, flufenacet, or acetochlor in four experiments. Compared to the weed free control, sorghum stand establishment was reduced 18% with the 2× rate of flufenacet at Colby in 2006. At Hays in 2005, stand reductions occurred with acetochlor or KIH-485 at the 2× rates and either rate of flufenacet. Averaged over experiments, grain yields were reduced 9 and 10% with KIH-485 and flufenacet at the 2× rates, respectively. Where precipitation was greatest during the 2 wk following herbicide application, weed control was the best with these herbicides, but sorghum injury was also greatest.

Drip-applied metam potassium and herbicides as methyl bromide alternatives for Cyperus control in tomato

Field trials were conducted to determine the efficacy of pre-emergence herbicides and metam potassium (metam-K) on density of a mixed stand of Cyperus esculentus and Cyperus rotundus in tomato ( Solanum lycopersicum L.). Treatments consisted of a combination of doses and application methods of the herbicides napropamide + S-metolachlor (2.3 + 1.5 kg a.i./ha) and EPTC (4.0 kg a.i./ha), as well as the presence or not of drip-applied metam-K (400 kg a.i./ha). A non-treated control and a grower standard (methyl bromide + chloropicrin) were added. Results indicated that drip-applied EPTC was injurious to tomato, while the drip-applied combination of napropamide + S-metolachlor was ineffective against the weed. The best combinations were obtained with bed top applications of either napropamide + S-metolachlor or EPTC followed by metam-K, which provided similar levels of Cyperus control and tomato yields to methyl bromide + chloropicrin treated plots.

Pre-emergence Liverwort Control in Nursery Containers

Experiments were conducted in Auburn, AL, and Aurora, OR, to evaluate herbicides for pre-emergence liverwort (Marchantia polymorpha) control. Granular pre-emergence herbicide efficacy varied by location and product. Summarizing across all experiments, flumioxazin and oxadiazon provided the most effective control in Alabama, whereas flumioxazin and oxyfluorfen + oryzalin provided the most effective control in Oregon. Sprayed quinoclamine provided pre-emergence liverwort control, but efficacy and duration of control were reduced compared with granular herbicides.

The efficacy of pre-emergence herbicides on problem weeds in woodland regeneration

Weeds germinating from seed are serious competitors for resources with young trees and can delay or prevent woodland establishment and regeneration. However, there is only limited information available on which pre-emergence herbicides are effective on problem weeds that commonly occur in these situations, in particular for perennial species germinating on fertile ex agricultural sites. Following previously reported glasshouse screening experiments for potentially useful herbicide treatments, ten residual herbicide treatments were tested on twelve problem weed species in the field. The results showed considerable variations in the susceptibilities of weed species to the different herbicide treatments. The combination of atrazine plus cyanazine, included as a standard herbicide mix that is commonly used in forestry situations, was the most effective treatment overall, with most weed species appearing to be susceptible or moderately susceptible. Chamerion angustifolium (rosebay willowherb) was the most sensitive species tested, being well controlled by the mixture of atrazine plus cyanazine, metazachlor, the higher doses of napropamide, and the mixture of metazachlor plus pendimethalin. Cirsium arvense (creeping thistle) was susceptible to isoxaben, and atrazine plus cyanazine. Clematis vitalba (old man's beard) was susceptible to isoxaben . Senecio vulgaris (groundsel) was well controlled by atrazine plus cyanazine, and metazachlor. Ranunculus repens (creeping buttercup) only appeared to be controlled by napropamide. Rumex obtusifolius (broadleaved dock) and Urtica dioica (common nettle) were susceptible to pendimethalin. Rubus fruticosus agg. (bramble), Cirsium vulgare (spear thistle) , Senecio jacobea (common ragwort) and Trifolium repens (white clover) were only susceptible to the mixture of atrazine plus cyanazine. Brassica napus ssp. oleifera (volunteer oilseed rape) was not completely controlled by any of the treatments, although atrazine plus cyanazine did give significant growth reductions. A comparison of the susceptibility implied by existing literature, glasshouse pot experiments and the field trials reported here, shows the importance of confirming results obtained in pot trials with field testing and provides valuable information on efficacy which will be useful in assisting herbicide selection in the future.

Effect of Brown Patch (Caused by Rhizoctonia solani) Control on Preemergence Herbicide Efficacy in Tall Fescue (Festuca arundinacea)1

Field studies evaluated the effect of brown patch control on preemergence herbicide efficacy in tall fescue. Pendimethalin (1.7 followed by [fb] 1.7; 3.4 kg ai/ha), prodiamine (0.7 fb 0.6; 1.3 kg ai/ha), and oxadiazon (2.2 fb 2.2; 4.5 kg/ha), applied sequentially and as a single application, were evaluated for smooth crabgrass control with and without the use of azoxystrobin, a fungicide that controls brown patch. Azoxystrobin suppressed brown patch and increased smooth crabgrass control with pendimethalin in both years. This enhanced efficacy with azoxystrobin was attributed to improved tall fescue turf density and thus increased competition between this turf species and smooth crabgrass. Longer soil-residual herbicides such as oxadiazon and prodiamine provided high levels of smooth crabgrass control (often >90%). With the exception of oxadiazon at 4.5 kg ai/ha in 2000, smooth crabgrass control with oxadiazon and prodiamine was unaffected by the use of azoxystrobin. Nomenclature: Azoxystrobin, methyl (E)...

Efficacy of Pre-emergence Herbicides on the Yield and Yield Components of Canola

Efficacy of Pre-emergence Herbicides on the Yield and Yield Components of Canola

Tolerance of Seashore Paspalum Cultivars to Preemergence Herbicides

Abstract The efficacy of preemergence herbicides among seashore paspalum (Paspalum vaginatum Swartz) cultivars used for summer annual weed control is limited. No differences were found in turfgrass tolerance among four paspalum cultivars from preemergence herbicides during 1996 and 1997 at Griffin, GA. The tolerance of paspalum turfgrass was good when treated with Ronstar (oxadiazon) at rates ≤ 10.1 kg/ha (9.0 lb/A), pendimethalin (various trade names, water-dispersible granules) or Barricade (prodiamine) at recommended rates [3.4 kg/ha (3.0 lb/A) and 0.8 kg/ha (0.7 lb/A), respectively]. When rates of these herbicides were increased to three times recommended, 15% injury was noted. During May 1996, Dimension (dithiopyr) injured the turf 12% when applied at the normal rate [0.6 kg/ha (0.5 lb/A)], but the injury was 35% in plots treated with three times recommended. Dimension did not cause any injury in 1997. Surflan (oryzalin) at 3.4 kg/ha (3.0 lb/A) and XL (benefin + oryzalin) at 3.4 kg/ha (3.0 lb/A) caused a maximum of 26% and 20% injury, respectively, when applied at the recommended rates. Maximum injury ranged from 48% for Surflan and 38% for XL when applied to plots at the three times recommended. The quality of PI 509018-1, SIPV-2, and AP-10 was generally higher than Adalayd from early spring until late August both years.