Nonvertical Spray Angles Optimize Graminicide Efficacy

Annual grasses constitute a major weed problem in winter annual crops in Northern Europe and especially in cropping systems where ploughing is omitted. At the optimum growth stage for control with POST herbicides, grasses have a predominantly vertical leaf orientation. This represents a very difficult spray target using the standard technique where nozzles are mounted more or less vertically downward. In this study, efficacy of the foliar-acting herbicide, haloxyfop, on perennial ryegrass at the two- to three-leaf stage was investigated in field experiments using some alternative configurations of nozzle mounting on the sprayer. Angling the spray either forward or backward relative to the direction of travel increased herbicide efficacy using standard commercially available flat-fan and pre-orifice nozzles. Efficacy increased generally with increasing angling relative to vertically downward and the forward-angled spray improved efficacy most. The largest improvement in efficacy was obtained using a 60° forward-angled spray in combination with a reduced boom height. Using this configuration, herbicide dose could be reduced by approximately 30% without loss of efficacy in comparison with the standard vertical mounting of nozzles. There was no advantage of using combinations of forward- and backward-angled nozzles.

Download Full-text

Cropping Systems to Control Winter Annual Grasses in Winter Wheat (Triticum aestivum)

Weed Technology ◽

10.1017/s0890037x00045012 ◽

1999 ◽

Vol 13 (1) ◽

pp. 120-126 ◽

Cited By ~ 32

Author(s):

Oleg Daugovish ◽

Drew J. Lyon ◽

David D. Baltensperger

Keyword(s):

Winter Wheat ◽

Cropping Systems ◽

Field Studies ◽

Downy Brome ◽

Jointed Goatgrass ◽

Long Term Effect ◽

Annual Grasses ◽

Winter Annual ◽

Feral Rye

Field studies were conducted from 1990 through 1997 to evaluate the long-term effect of 2- and 3-yr rotations on the control of downy brome, jointed goatgrass, and feral rye in winter wheat. At the completion of the study, jointed goatgrass and feral rye densities averaged 8 plants/m2and < 0.1 plant/m2for the 2- and 3-yr rotations, respectively. Downy brome densities averaged < 0.5 plant/m2for both the 2- and 3-yr rotations, with no treatment differences observed. Winter annual grasses were not eradicated after two cycles of the 3-yr rotations, but weed densities were reduced 10-fold compared to densities after one cycle and more than 100-fold compared with the 2-yr rotations. Wheat grain contamination with dockage and foreign material followed a similar trend. The 3-yr rotations were economically competitive with 2-yr rotations and provided superior control of the winter annual grass weeds.

Download Full-text

Cover Crop and Postemergence Herbicide Integration for Palmer amaranth Control in Cotton

Weed Technology ◽

10.1017/wet.2017.10 ◽

2017 ◽

Vol 31 (3) ◽

pp. 348-355 ◽

Cited By ~ 3

Author(s):

Matthew S. Wiggins ◽

Robert M. Hayes ◽

Robert L. Nichols ◽

Lawrence E. Steckel

Keyword(s):

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Field Experiments ◽

Palmer Amaranth ◽

Cereal Rye ◽

Crimson Clover ◽

Annual Grasses ◽

Winter Annual ◽

Hand Weeding

Field experiments were conducted to evaluate the integration of cover crops and POST herbicides to control glyphosate-resistant Palmer amaranth in cotton. The winter-annual grasses accumulated the greatest amount of biomass and provided the most Palmer amaranth control. The estimates for the logistic regression would indicate that 1540 kg ha−1would delay Palmer amaranth emerging and growing to 10 cm by an estimated 16.5 days. The Palmer amaranth that emerged in the cereal rye and wheat cover crop treatments took a longer time to reach 10 cm compared to the hairy vetch and crimson clover treatments. POST herbicides were needed for adequate control of Palmer amaranth. The glufosinate-based weed control system provided greater control (75% vs 31%) of Palmer amaranth than did the glyphosate system. These results indicate that a POST only herbicide weed management system did not provide sufficient control of Palmer amaranth, even when used in conjunction with cover crops that produced a moderate level of biomass. Therefore, future recommendations for GR Palmer amaranth control will include integrating cover crops with PRE herbicides, overlaying residual herbicides in-season, timely POST herbicide applications, and hand weeding in order to achieve season-long control of this pest.

Download Full-text

Interference of Three Annual Grasses with Grain Sorghum (Sorghum bicolor)

Weed Technology ◽

10.1017/s0890037x00025343 ◽

1990 ◽

Vol 4 (2) ◽

pp. 245-249 ◽

Cited By ~ 19

Author(s):

Brenda S. Smith ◽

Don S. Murray ◽

J. D. Green ◽

Wan M. Wanyahaya ◽

David L. Weeks

Keyword(s):

Linear Regression ◽

Grain Yield ◽

Field Experiments ◽

Grain Sorghum ◽

Grass Species ◽

Row Spacing ◽

Yield Data ◽

Weed Density ◽

Annual Grasses ◽

Wide Row Spacing

Barnyardgrass, large crabgrass, and Texas panicum were evaluated in field experiments over 3 yr to measure their duration of interference and density on grain sorghum yield. When grain yield data were converted to a percentage of the weed-free control, linear regression predicted a 3.6% yield loss for each week of weed interference regardless of year or grass species. Grain sorghum grown in a narrow (61-cm) row spacing was affected little by full-season interference; however, in wide (91-cm) rows, interference increased as grass density increased. Data from the wide-row spacing were described by linear regression following conversion of grain yield to percentages and weed density to log10. A separate nonlinear model also was derived which could predict the effect of weed density on grain sorghum yield.

Download Full-text

Comparative Experimental Effects of Intercropping and Cypermethrin on Insect Pest Infestation and Yield of Maize, Cowpea and Okra in Two Cameroonian Agro-Ecological Zones

AgriEngineering ◽

10.3390/agriengineering3020025 ◽

2021 ◽

Vol 3 (2) ◽

pp. 383-393

Author(s):

Patient Farsia Djidjonri ◽

Nukenine Elias Nchiwan ◽

Hartmut Koehler

Keyword(s):

Field Experiments ◽

Insect Pests ◽

Cropping Systems ◽

Insect Pest ◽

Maize Yield ◽

Ecological Zones ◽

Pest Infestation ◽

Final Yield ◽

Cropping Seasons ◽

Agro Ecological Zones

The present study investigates the effect of intercropping (maize-cowpea, maize-okra, maize-okra-cowpea, okra-cowpea) compared to insecticide application on the level of infestation of insect pests and the final yield of maize, cowpea and okra. Field experiments were conducted during the 2016 and 2017 cropping seasons in the Guinean Savannah (Dang-Ngaoundere) and Sudano Sahelian (Gouna-Garoua) agro-ecological zones in Cameroon. Our experimental design was a split plot arrangement in a randomized complete block with four replications. The main factor was assigned to the use of insecticide (Cypermethrin) and sub plots were devoted for cropping systems. We compared the efficiency of intercropping to that of Cypermethrin application on the Yield of maize, cowpea and okra as influenced by insect pest damages. The comparison of monocropped sprayed by Cypermethrin to unsprayed showed that, in Dang, insect pests reduced maize yield by 37% and 24% in 2016 and 2017, respectively, whereas in Gouna, it was lower than 8% during the both years. Reduction in seed yield by insect pests on cowpea in Dang represented 47% and 50% in 2016 and 2017, respectively, whereas in Gouna, it was 55% and 63% in 2016 and 2017, respectively. For okra, insect pests reduced okra fruit yield by 25% and 44% in Dang and 23% and 28% in Gouna, respectively, in 2016 and 2017. Crop yield was lower in intercropping compared to monoculture due to competition of plants in association on different resources. Considering the total yields obtained from each intercropping, intercropping trials resulted generally in higher yields compared to mono-culture (LER > 1) in both sites and years but the respective yields were quite different. On the basis of the results obtained, we recommend maize-cowpea intercropping as a sustainable solution to reduce the infestation level of their pest insects.

Download Full-text

Palweed:Wheat: A Bioeconomic Decision Model for Postemergence Weed Management in Winter Wheat (Triticum aestivum)

Weed Science ◽

10.1017/s0043174500081704 ◽

1995 ◽

Vol 43 (4) ◽

pp. 595-603 ◽

Cited By ~ 14

Author(s):

Tae-Jin Kwon ◽

Douglas L. Young ◽

Frank L. Young ◽

Chris M. Boerboom

Keyword(s):

Winter Wheat ◽

Weed Management ◽

Decision Model ◽

Damage Function ◽

Yield Response ◽

Density Functions ◽

Yield Model ◽

Weed Density ◽

Annual Grasses ◽

Winter Annual

Based on six years of data from a field experiment near Pullman, WA, a bioeconomic decision model was developed to annually estimate the optimal post-emergence herbicide types and rates to control multiple weed species in winter wheat under various tillage systems and crop rotations. The model name, PALWEED:WHEAT, signifies a Washington-Idaho Palouse region weed management model for winter wheat The model consists of linear preharvest weed density functions, a nonlinear yield response function, and a profit function. Preharvest weed density functions were estimated for four weed groups: summer annual grasses, winter annual grasses, summer annual broadleaves, and winter annual broadleaves. A single aggregated weed competition index was developed from the four density functions for use functions for use in the yield model. A yield model containing a logistic damage function performed better than a model containing a rectangular hyperbolic damage function. Herbicides were grouped into three categories: preplant nonselective, postemergence broadleaf, and postemergence grass. PALWEED:WHEAT was applied to average conditions of the 6-yr experiment to predict herbicide treatments that maximized profit. In comparison to average treatment rates in the 6-yr experiment, the bioeconomic decision model recommended less postemergence herbicide. The weed management recommendations of PALWEED:WHEAT behaved as expected by agronomic and economic theory in response to changes in assumed weed populations, herbicide costs, crop prices, and possible restrictions on herbicide application rates.

Download Full-text

Annual Grass Control in Alfalfa (Medicago sativa) with Postemergence Graminicides

Weed Technology ◽

10.1017/s0890037x00036514 ◽

1992 ◽

Vol 6 (4) ◽

pp. 938-948 ◽

Cited By ~ 2

Author(s):

Chester L. Foy ◽

Harold L. Witt

Keyword(s):

Medicago Sativa ◽

Field Experiments ◽

Annual Grass ◽

Giant Foxtail ◽

Herbicide Treatments ◽

Highly Effective ◽

Annual Grasses ◽

Large Crabgrass

Field experiments were conducted during 1982 to 1988 in Virginia to evaluate BAS 517, CGA 82725, clethodim, cloproxydim, fenoxaprop, fluazifop, fluazifop-P, haloxyfop, paraquat, quizalofop, SC-1084, sethoxydim, sethoxydim plus thifensulfuron, and terbacil for control of annual grasses in alfalfa. Herbicides were applied to alfalfa and grasses 2 to 30 cm in height after the first and/or second cuttings. Overall, the herbicides were highly effective in controlling fall panicum, giant foxtail, barnyardgrass, and large crabgrass. Alfalfa yields were not increased with herbicide treatments in several experiments. Only paraquat, applied later than recommended after cutting in one experiment, and sethoxydim plus thifensulfuron at one location reduced alfalfa yields.

Download Full-text

ANNUAL GRASSES CONTROL WITH TOPRAMEZONE IN MIXTURE WITH ALS-INHIBITING HERBICIDES

Planta Daninha ◽

10.1590/s0100-83582015000300013 ◽

2015 ◽

Vol 33 (3) ◽

pp. 509-519 ◽

Cited By ~ 1

Author(s):

C. A. DAMALAS ◽

T. K. GITSOPOULOS ◽

S.D. KOUTROUBAS ◽

I. GEORGOULAS

Keyword(s):

Growth Stage ◽

Leaf Growth ◽

Foxtail Millet ◽

Panicum Miliaceum ◽

Species Sensitivity ◽

Fresh Weight ◽

Pot Trials ◽

Annual Grasses ◽

Potential Interactions ◽

Selection Of

ABSTRACTPanicoid grasses are major weeds of maize and sugarcane as well as of several other important grains, including sorghum, pearl millet, and foxtail millet. Pot trials were conducted to study the activity and potential interactions of topramezone in mixture with recommended rates of rimsulfuron or nicosulfuron on three annual panicoid grasses (i.e. Echinochloa oryzoides,E.phyllopogon, and Panicum miliaceum). Target weeds were treated at the four- to five-leaf growth stage. On the basis of fresh weight reduction, topramezone alone provided 78% control of E.oryzoides, 68% control of E.phyllopogon, and 99% control of P.miliaceum. Topramezone plus rimsulfuron or nicosulfuron provided decreased control of both Echinochloa spp. compared with topramezone alone. The decreased control of E.oryzoidesand E.phyllopogon was more pronounced with rimsulfuron as a companion herbicide in the mixtures. Slightly decreased control of P.milaceum was observed with topramezone plus rimsulfuron compared with topramezone alone, but this was not the case for topramezone plus nicosulfuron. Increased topramezone rates mixed with rimsulfuron or nicosulfuron did not improve control of E.oryzoides and E.phyllopogon compared with the lowest topramezone rate. Also, increased topramezone rates mixed with rimsulfuron or nicosulfuron showed decreased control of both Echinochloa spp. when compared with either rimsulfuron or nicosulfuron alone, suggesting a two-way interaction between topramezone and the ALS-inhibiting herbicides. The above-mentioned interaction was not observed in P.miliaceum, probably related with species sensitivity to the herbicides tested. Newly introduced or naturalized panicoid grasses in maize fields may complicate selection of companion herbicides and rates for effective weed control.

Download Full-text

Effect of Spray Components on Glyphosate Toxicity to Annual Grasses

Weed Science ◽

10.1017/s0043174500068673 ◽

1983 ◽

Vol 31 (1) ◽

pp. 124-130 ◽

Cited By ~ 60

Author(s):

Douglas D. Buhler ◽

Orvin C. Burnside

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Plant Growth ◽

Surfactant Concentration ◽

Growth Stage ◽

Annual Grass ◽

Spray Solution ◽

Annual Grasses ◽

Small Grains ◽

Carrier Volume

Field and greenhouse research was conducted during 1980 and 1981 to evaluate the effects of carrier volume, surfactant concentration, and treatment date on glyphosate [N- (phosphonomethyl)glycine] toxicity to annual-grass weeds and volunteer small grains. Glyphosate phytotoxicity increased as carrier volume was decreased from 190 to 24 L/ha. The presence of a surfactant in the spray solution did not influence grass control when glyphosate was applied in a carrier volume of 24 L/ha. When glyphosate was applied in 48 or 95 L/ha, the presence of surfactant resulted in better grass control than glyphosate without surfactant. When applied in 190 L/ha, glyphosate with 0.5% (v/v) surfactant gave better grass control than glyphosate alone or commercially formulated glyphosate. When glyphosate was applied to plants under water stress, little control was achieved regardless of plant growth stage. Glyphosate application to grass after head initiation also resulted in reduced control. Maximum weed control with glyphosate was attained when applications were made to seedlings growing actively because of adequate soil moisture and favorable temperatures.

Download Full-text

Green house studies on the biology of winter annual grasses and the use of cover crops and herbicides for their control

Agronomy Journal of Nepal ◽

10.3126/ajn.v2i0.7529 ◽

2013 ◽

Vol 2 ◽

pp. 139-148 ◽

Cited By ~ 1

Author(s):

JD Ranjit ◽

R Bellinder ◽

C Benidict ◽

V Kumar

Keyword(s):

Plant Growth ◽

Cover Crops ◽

Plant Biomass ◽

Flag Leaf ◽

Biological Study ◽

Cornell University ◽

Green House ◽

Annual Grasses ◽

Winter Annual ◽

Preemergence Herbicides

Greenhouse studies were initiated in two small (Polypogon fugox) and large (Phalaris minor) seeded annual grasses in 2007 at Cornell University, Ithaca, NY USA. These two annual grasses were very common in wheat fields of midhills and terai regions of Nepal. P fugox was taken for biological study. Days to emergence took 8-11 days in green house. Early emerged panicles were longer than those emerged late. Panicle took 10-12 days to emerge completely from the flag leaf. Panicles per plant were 120. Seeds were very small having about 1091 seeds per panicle. So one fully matured plant could produce seeds about 130920. Study on eco-biology needs to continue in the future. P fugox and P minor responded differently to buckwheat residues. Among different treatments emergence and growth of both weeds were suppressed more by buckwheat residues when left on the surface than incorporated. P minor was less affected by buckwheat residues. It might be due to larger seed compared to P fugox. Post emergence herbicides clodinofop and pinoxaden were effective on both grasses. Isoproturon and tralkoxydim were effective on P fugox. Sulfosulfuron was good in reducing plant growth to some extent. Preemergence herbicides pendimethalin and s-metolochlor were effective in reducing emergence and growth of both weeds. Isoproturon and and sulfosulfuron suppressed plant growth reducing dry plant biomass. DOI: http://dx.doi.org/10.3126/ajn.v2i0.7529 Agronomy Journal of Nepal (Agron JN) Vol. 2: 2011 pp.139-148

Download Full-text