Increasing and Decreasing pH to Enhance the Biological Activity of Nicosulfuron

2005 ◽  
Vol 19 (2) ◽  
pp. 468-475 ◽  
Author(s):  
Jerry M. Green ◽  
Theresa Hale
Keyword(s):  
Biological Activity ◽  
Weak Acid ◽  
Neutral Form ◽  
Weed Species ◽  
Water Dispersible ◽  
Dispersed Particles ◽  
Hydrophilic Lipophilic Balance ◽  
Granule Formulation ◽  
Decreasing Ph ◽  
Large Crabgrass

Increasing the pH of the spray water to solubilize the weak acid herbicide nicosulfuron and then decreasing pH below its pKaso that it converts into a neutral form enhances biological activity under some conditions. The water-dispersible granule formulation of nicosulfuron starts as dispersed particles. Adding 1% wt/wt K3PO4solubilizes nicosulfuron and increases its activity compared to its dispersion without base. The type of buffer and the surfactant HLB or hydrophilic lipophilic balance, a measure of the molecular balance of the hydrophilic and lipophilic groups, altered the activity of nicosulfuron. Adding 1% wt/wt K3PO4increases the pH, and the optimum HLB ranged from 13 to 17 on large crabgrass. Adding 1% wt/wt H3PO4reduces the pH and lowers the optimum HLB range from 10 to 14 on large crabgrass. Adding the acidic buffer converts the solubilized nicosulfuron into its neutral form and increases activity under some surfactant conditions. Thus, neutral nicosulfuron is more active with lipophilic surfactants, while ionic nicosulfuron is more active with hydrophilic surfactants. When tested on other species, low HLB surfactants are the most active at low pH. These results support the concept that the physicochemical properties of the herbicide, adjuvants, and weed species should be matched for optimum activity.

Absorption, Translocation, and Metabolism of14C-Glufosinate in Glufosinate-Resistant Corn, Goosegrass (Eleusine indica), Large Crabgrass (Digitaria sanguinalis), and Sicklepod (Senna obtusifolia)

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Wesley J. Everman ◽  
Cassandra R. Mayhew ◽  
James D. Burton ◽  
Alan C. York ◽  
John W. Wilcut
Keyword(s):  
Weed Species ◽  
Digitaria Sanguinalis ◽  
Eleusine Indica ◽  
Leaf Stage ◽  
Senna Obtusifolia ◽  
Harvest Timing ◽  
Treated Leaf ◽  
Harvest Intervals ◽  
Corn Plants ◽  
Large Crabgrass

Greenhouse studies were conducted to evaluate14C-glufosinate absorption, translocation, and metabolism in glufosinate-resistant corn, goosegrass, large crabgrass, and sicklepod. Glufosinate-resistant corn plants were treated at the four-leaf stage, whereas goosegrass, large crabgrass, and sicklepod were treated at 5, 7.5, and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption was less than 20% at all harvest intervals for glufosinate-resistant corn, whereas absorption in goosegrass and large crabgrass increased from approximately 20% 1 HAT to 50 and 76%, respectively, 72 HAT. Absorption of14C-glufosinate was greater than 90% 24 HAT in sicklepod. Significant levels of translocation were observed in glufosinate-resistant corn, with14C-glufosinate translocated to the region above the treated leaf and the roots up to 41 and 27%, respectively. No significant translocation was detected in any of the weed species at any harvest timing. Metabolites of14C-glufosinate were detected in glufosinate-resistant corn and all weed species. Seventy percent of14C was attributed to glufosinate metabolites 72 HAT in large crabgrass. Less metabolism was observed for sicklepod, goosegrass, and glufosinate-resistant corn, with metabolites composing less than 45% of detectable radioactivity 72 HAT.

scholarly journals Effects of Three Fertilization Methods on Weed Growth and Herbicide Performance in Soilless Nursery Substrates1

2018 ◽  
Vol 36 (4) ◽  
pp. 133-139
Author(s):  
Cody J. Stewart ◽  
S. Christopher Marble ◽  
Brian E. Jackson ◽  
Brian J. Pearson ◽  
P. Christopher Wilson
Keyword(s):  
Fertilizer Treatment ◽  
Fertility Rates ◽  
Weed Species ◽  
Fertilizer Placement ◽  
Digitaria Sanguinalis ◽  
Fertilizer Rate ◽  
Weed Growth ◽  
Eclipta Prostrata ◽  
Preemergence Herbicides ◽  
Large Crabgrass

Abstract Research objectives were to determine the effect of fertilization method (incorporation, subdress, and topdress) on weed growth and the performance of preemergence herbicides applied to soilless substrates. Nursery containers were filled with a pine bark:peat substrate and fertilized at two different rates [4.4 and 9.5 kg.m−3 (8.9 and 19.2 lb.yd−3)] via topdressing, subdressing, or incorporating. Containers were treated with either dimethenamid-P for spotted spurge (Euphorbia maculata L.), flumioxazin for eclipta (Eclipta prostrata L.) or prodiamine for large crabgrass (Digitaria sanguinalis L.). A control was established for each fertilizer rate/placement and weed species that was not treated. Incorporating or subdressing fertilizer resulted in reduced large crabgrass and spotted spurge growth in non-treated containers. Weeds grew larger at the higher fertility rates in both topdress and incorporated treatments but fertilizer rate did not affect growth of spotted spurge or large crabgrass when fertilizers were subdressed. Herbicides generally provided commercially acceptable weed control regardless of fertilizer treatment, but results varied with species. Results suggest that in the absence of herbicides, topdressing may result in greater weed growth compared with subdressing or incorporating fertilizers; however, fertilizer placement will have less impact on herbicide performance if proper herbicides are chosen and applied correctly. Index words: topdress, subdress, incorporate, large crabgrass, eclipta, spotted spurge, preemergence Chemicals used in this study: Flumioxazin (SureGuard®); 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole1,3(2H)-dione; Dimethenamid-P (Tower) 2-chloro-N-[(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide; Prodiamine (Barricade) 2,4-dinitro-N3, N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine (Barricade®) Species used in this study: Large crabgrass (Digitaria sanguinalis L.); Eclipta (Eclipta prostrata L.); Spotted spurge (Euphorbia maculata L.)

Interaction of Prodiamine and Flumioxazin for Nursery Weed Control

2010 ◽  
Vol 24 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Stephen C. Marble
Keyword(s):  
United States ◽  
Weed Control ◽  
Southeastern United States ◽  
Cost Effective ◽  
Fresh Weight ◽  
Weed Species ◽  
Rate Range ◽  
Nursery Production ◽  
Control Research ◽  
Large Crabgrass

Both prodiamine and flumioxazin are used in the nursery production and landscape maintenance industries in the southeastern United States for preemergence weed control. Research was conducted to determine whether a tank mixture of these two herbicides would be more effective than either component applied alone. Prodiamine alone, flumioxazin alone, and a 72 : 28 (by weight) prodiamine–flumioxazin mixture were each applied at a series of rates to containers filled with a pine bark–sand substrate that is typical for nursery production in the southeastern United States. Our intent was to have a rate range that hopefully extended from ineffective to lethal for each treatment series. Subsequent to treatment, containers were overseeded with either large crabgrass, spotted spurge, or eclipta. Percent control was determined by comparing treated weed foliage fresh weight to that of the appropriate nontreated control at 6 and 12 wk after application. ANOVA followed by nonlinear regression was used to evaluate the interaction of prodiamine and flumioxazin when combined and to determine the rate of each treatment series required for 95% control (if applicable) for each of the three weed species. Results varied with weed species. The mixture was synergistic and more cost effective than either of the components applied alone in controlling spotted spurge. With respect to large crabgrass control, the mixture was additive and slightly more cost effective than the components. Eclipta could only be controlled with flumioxazin, and this control was antagonized by the addition of prodiamine.

Utility of Clomazone for Annual Grass and Broadleaf Weed Control in Peanut (Arachis hypogaea)

1994 ◽  
Vol 8 (1) ◽  
pp. 23-27 ◽  
Author(s):  
David L. Jordan ◽  
John W. Wilcut ◽  
Leslie D. Fortner
Keyword(s):  
Weed Control ◽  
Arachis Hypogaea ◽  
Field Experiments ◽  
Systems Approach ◽  
Annual Grass ◽  
Weed Species ◽  
Common Ragweed ◽  
Prickly Sida ◽  
Better Than ◽  
Large Crabgrass

Field experiments conducted in 1988 and 1989 evaluated clomazone alone and in a systems approach for weed control in peanut. Clomazone PPI at 0.8 kg ai/ha controlled common ragweed, prickly sida, spurred anoda, and tropic croton better than ethalfluralin and/or metolachlor applied PPI. POST application of acifluorfen plus bentazon was not needed to control these weeds when clomazone was used. Acifluorfen plus bentazon improved control of these weeds when clomazone was not used and generally were necessary to obtain peanut yields regardless of the soil-applied herbicides. Alachlor PRE did not improve clomazone control of any weed species evaluated. Fall panicum and large crabgrass control was similar with clomazone or clomazone plus ethalfluralin.

Winter Annual Broadleaf Weeds and Winter Wheat Response to Postemergence Application of Two Saflufenacil Formulations

2010 ◽  
Vol 24 (4) ◽  
pp. 416-424 ◽  
Author(s):  
John C. Frihauf ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier ◽  
Dallas E. Peterson
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Field Experiments ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Water Dispersible ◽  
Leaf Necrosis ◽  
Winter Annual ◽  
Rate Formulation ◽  
Water Dispersible Granule

Field experiments in winter wheat were initiated at two locations in the fall of 2006 and 2007 to evaluate winter annual broadleaf weeds and winter wheat response to POST applications of two saflufenacil formulations applied alone and in combination with 2,4-D amine. Emulsifiable concentrate (EC) and water-dispersible granule (WG) formulations of saflufenacil at 13, 25, and 50 g ai ha−1were applied with 1.0% (v/v) crop oil concentrate (COC) and mixed with 2,4-D amine at 533 g ae ha−1without adjuvant. Regardless of rate or formulation, saflufenacil plus COC and saflufenacil plus 2,4-D amine controlled blue mustard ≥ 91% at 17 to 20 d after treatment (DAT) compared with ≤ 50% control with 2,4-D amine alone. At least 25 g ha−1of saflufenacil EC was necessary to control flixweed > 90%. Excluding COC from saflufenacil plus 2,4-D amine reduced flixweed control from the saflufenacil WG formulation more than the EC formulation. Most saflufenacil treatments did not control henbit satisfactorily (≤ 80%). Wheat foliar necrosis increased with increasing saflufenacil rate to as high as 30% at 3 to 6 DAT, but declined to < 15% at 10 to 20 DAT and was not evident at 30 DAT. Saflufenacil rate, formulation, and mixing with 2,4-D amine also influenced wheat stunting, but to a lesser extent than foliar necrosis. Saflufenacil EC consistently caused greater foliar necrosis and stunting on wheat than saflufenacil WG. Leaf necrosis and stunting were reduced by tank-mixing saflufenacil formulations with 2,4-D amine without COC. Grain yields of most saflufenacil treatments were similar to 2,4-D amine under weedy conditions and herbicide treatments had no effect on grain yield in weed-free experiments. Saflufenacil formulations at 25 to 50 g ha−1with 2,4-D amine and saflufenacil WG at 25 to 50 g ha−1with COC can control winter annual broadleaf weeds with minimal injury (< 15%) and no grain yield reductions. The addition of saflufenacil as a POST-applied herbicide would give wheat growers another useful tool to control annual broadleaf weeds, including herbicide-resistant weed species.

Preparation of nanocomposite polypyrrole/cellulose nanocrystals for conductive paper

2018 ◽  
Vol 33 (2) ◽  
pp. 309-316
Author(s):  
Ahmed A. Al-Dulaimi ◽  
W.D. Wanrosli ◽  
Lway Faisal Abdulrazak ◽  
M. Husham
Keyword(s):  
Electrical Properties ◽  
Cellulose Nanocrystals ◽  
Ph Value ◽  
Paper Sheet ◽  
Elongation At Break ◽  
Conductive Paper ◽  
Water Dispersible ◽  
Decreasing Ph ◽  
The Stability ◽  
Polymerization Method

AbstractThe preparation of conductive polypyrrole (PPy) nanocomposite with cellulose nanocrystals (CNC) was carried out by situ polymerization method. The new water dispersible sample (PPy-CNC) was deposited as a thin film on the paper sheet substrate as a conductive paper. The images of field emission scanning electron microscopy (FESEM) clearly shw the morphological modulation and the uniformity of the PPy-CNC sample. The electrical properties of conductive paper were studied with various acid doping values. The results show increase in the electrical properties along with the decrease of pH value. Cyclic voltammetry (CV) test was used to examine the stability of redox properties of the neat sample before the doping process. The mechanical properties such as tensile index and elongation at break shows slight decline with decreasing pH. However, elongation at break results for 0.65 pH sample shows different respond to pH value.

Weed Seed Contamination of Cotton Gin Trash

2009 ◽  
Vol 23 (4) ◽  
pp. 574-580 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Kenneth L. Smith ◽  
Lawrence E. Steckel ◽  
Clifford H. Koger
Keyword(s):  
Surface Layer ◽  
Palmer Amaranth ◽  
Weed Seed ◽  
Weed Species ◽  
Cattle Feed ◽  
Material Development ◽  
Crop Fields ◽  
Viable Seeds ◽  
Prickly Sida ◽  
Large Crabgrass

Cotton gins in Arkansas, western Tennessee, and western Mississippi were sampled for weed seed contamination of gin trash in fall 2007. A total of 473 samples were collected, with 453 samples from Arkansas. The objectives of this research were to determine the weed species most frequently found in gin trash and determine what means gin operators are using to dispose of gin trash. There were 25 weed species found in the gin trash samples—11 grass and 14 broadleaf weeds. Grass and broadleaf weeds were present in 41.4 and 8.5% of the samples, respectively. The most frequently found species were large crabgrass (19.0%), barnyardgrass (14.0%), goosegrass (12.9%), red sprangletop (8.2%) and Palmer amaranth (4.2%). Viable seeds of barnyardgrass, large crabgrass, Palmer amaranth, and prickly sida were present in the surface layer (0- to 25-cm depth) of gin trash piles after 1 yr of composting. Viable Palmer amaranth seeds were present in the surface layer of gin trash piles after 2 yr of composting, but no germinable seeds were found deeper than 25 cm following 1 yr of composting. Gin trash disposal involved application of the material to crop fields during the fall or winter months; composting followed by application of the compost as mulch or a soil amendment to gardens, flower beds, or crop fields; use as cattle feed; and coverage for landfills to reduce erosion and encourage growth of vegetation. Because of the demonstrated potential for weed seed dispersal via gin trash, including composted material, development of technologies to ensure disposal of a gin-trash product free of viable weed seed are justified.

Sign in / Sign up

Export Citation Format

Share Document