Control of glyphosate-resistant horseweed and giant ragweed in soybean with halauxifen-methyl applied preplant

2020 ◽  
pp. 1-20
Author(s):  
Jessica Quinn ◽  
Jamshid Ashigh ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

Abstract Horseweed and giant ragweed are competitive, annual weeds that can negatively impact crop yield. Biotypes of glyphosate-resistant (GR) giant ragweed and horseweed were first reported in 2008 and 2010 in Ontario, respectively. GR horseweed has spread throughout the southern portion of the province. The presence of GR biotypes poses new challenges for soybean producers in Canada and the United States. Halauxifen-methyl is a recently registered selective herbicide for broadleaf weeds, for preplant use in corn and soybean. There is limited literature on the efficacy of halauxifen-methyl on GR horseweed and giant ragweed when combined with currently registered products in Canada. The purpose of the experiment was to determine the effectiveness of halauxifen-methyl applied alone, and tank-mixed for GR giant ragweed and GR horseweed control in glyphosate and dicamba-resistant (GDR) soybean in southwestern Ontario. Six field experiments were conducted separately for each weed species over 2018 and 2019. Halauxifen-methyl applied alone controlled GR horseweed 72% at 8 weeks after application (WAA). Control was improved to >91% when halauxifen-methyl applied in combination with metribuzin, saflufenacil, chlorimuron-ethyl + metribuzin and saflufenacil + metribuzin. At 8 WAA, halauxifen-methyl controlled GR giant ragweed 11%; glyphosate/2,4-D choline, glyphosate/dicamba, glyphosate/2,4-D choline + halauxifen-methyl and glyphosate/dicamba + halauxifen-methyl controlled GR giant ragweed 76 to 88%. This study concluded that halauxifen-methyl applied preplant in a tank-mixture can provide effective control of GR giant ragweed and horseweed in GDR soybean.

2020 ◽  
Vol 34 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Jessica Quinn ◽  
Nader Soltani ◽  
Jamshid Ashigh ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.


2020 ◽  
pp. 1-8
Author(s):  
Chandrima Shyam ◽  
Parminder S. Chahal ◽  
Amit J. Jhala ◽  
Mithila Jugulam

Abstract Glyphosate-resistant (GR) Palmer amaranth is a problematic, annual broadleaf weed in soybean production fields in Nebraska and many other states in the United States. Soybean resistant to 2,4-D, glyphosate, and glufosinate (Enlist E3TM) has been developed and was first grown commercially in 2019. The objectives of this research were to evaluate the effect of herbicide programs applied PRE, PRE followed by (fb) late-POST (LPOST), and early-POST (EPOST) fb LPOST on GR Palmer amaranth control, density, and biomass reduction, soybean injury, and yield. Field experiments were conducted near Carleton, NE, in 2018, and 2019 in a grower’s field infested with GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean. Sulfentrazone + cloransulam-methyl, imazethapyr + saflufenacil + pyroxasulfone, and chlorimuron ethyl + flumioxazin + metribuzin applied PRE provided 84% to 97% control of GR Palmer amaranth compared with the nontreated control 14 d after PRE. Averaged across herbicide programs, PRE fb 2,4-D and/or glufosinate, and sequential application of 2,4-D or glufosinate applied EPOST fb LPOST resulted in 92% and 88% control of GR Palmer amaranth, respectively, compared with 62% control with PRE-only programs 14 d after LPOST. Reductions in Palmer amaranth biomass followed the same trend; however, Palmer amaranth density was reduced 98% in EPOST fb LPOST programs compared with 91% reduction in PRE fb LPOST and 76% reduction in PRE-only programs. PRE fb LPOST and EPOST fb LPOST programs resulted in an average soybean yield of 4,478 and 4,706 kg ha−1, respectively, compared with 3,043 kg ha−1 in PRE-only programs. Herbicide programs evaluated in this study resulted in no soybean injury. The results of this research illustrate that herbicide programs are available for the management of GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean.


Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 170-179 ◽  
Author(s):  
Menashe Horowitz ◽  
Yael Regev ◽  
Geza Herzlinger

Solarization is a method of heating moist soil by covering it with plastic sheets to trap solar radiation. In field experiments in Israel during the summer, maximum soil temperature under plastic cover at the 5-cm depth averaged 46 to 49C. No weeds emerged under the plastic cover during solarization and weed emergence was reduced after its removal. The heating effect from solarization decreased with soil depth. Concentration of O2 in soil under plastic was similar to that in uncovered controls, but the concentration of CO2 was markedly higher than in control soil, rising up to 2.4%. Higher temperatures and better residual weed control were produced by transparent than by black plastic, with best results from thin (0.03 mm), transparent polyethylene. Under Israeli summer conditions, 2 to 4 weeks of solarization produced effective control of annual weeds that was still appreciable after 1 yr. Narrow sheets of 20 to 50 cm produced effective weed control in bands. on soil irrigated once before placing the plastic sheets, there was no need to irrigate during solarization. The response of weed species to solarization differed. Many annual weeds, both summer species such as pigweed (Amaranthus spp.) and common purslane (Portulaca oleracea L.) and winter species as henbit (Lamium amplexicaule L.) were well controlled by solarization. Broomrape (Orobanche crenata Forsk.) was controlled in one experiment. on the other hand, horseweed [Conyza canadensis (L.) Cronq.] and bull mallow (Malva niceaensis All.) were relatively resistant, and established perennials escaped the treatment.


2021 ◽  
pp. 1-21
Author(s):  
Jose H. S. de Sanctis ◽  
Amit J. Jhala

Abstract Velvetleaf is an economically important weed in agronomic crops in Nebraska and the United States. Dicamba applied alone usually does not provide complete velvetleaf control, particularly when velvetleaf is greater than 15 cm tall. The objectives of this experiment were to evaluate the interaction of dicamba, fluthiacet-methyl, and glyphosate applied alone or in a mixture in two- or three-way combinations for velvetleaf control in dicamba/glyphosate-resistant (DGR) soybean and to evaluate whether velvetleaf height (≤ 12 cm or ≤ 20 cm) at the time of herbicide application influences herbicide efficacy, velvetleaf density, biomass, and soybean yield. Field experiments were conducted near Clay Center, Nebraska in 2019 and 2020. The experiment was arranged in a split-plot with velvetleaf height (≤ 12 cm or ≤ 20 cm) as the main plot treatment and herbicides as sub-plot treatment. Fluthiacet provided ≥ 94% velvetleaf control 28 d after treatment (DAT) and ≥ 96% biomass reduction regardless of application rate or velvetleaf height. Velvetleaf control was 31% to 74% at 28 DAT when dicamba or glyphosate was applied alone to velvetleaf ≤ 20 cm tall compared with 47% to 100% control applied to ≤ 12 cm tall plants. Dicamba applied alone to ≤ 20 cm tall velvetleaf provided < 75% control and < 87% biomass reduction 28 DAT compared with ≥ 90% control with dicamba at 560 g ae ha−1 + fluthiacet at 7.2 g ai ha−1 or glyphosate at 1,260 g ae ha−1. Dicmaba at 280 g ae ha−1 + glyphosate at 630 g ae ha−1 applied to ≤ 20 cm tall velvetleaf resulted in 86% control 28 DAT compared with the expected 99% control. The interaction of dicamba + fluthiacet + glyphosate was additive for velvetleaf control and biomass reduction regardless of application rate and velvetleaf height.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.


1989 ◽  
Vol 52 (8) ◽  
pp. 595-601 ◽  
Author(s):  
EWEN C. D. TODD

Although the full economic impact of foodborne diseases has yet to be measured, preliminary studies show that the cost of illness, death, and business lost is high indeed. This impact is probably greatest in developing countries, but few facts are known. For the United States, preliminary estimates are 12.6 million cases costing $8.4 billion. These may seem excessive but other authors have postulated even higher case and dollar figures. Microbiological diseases (bacterial and viral) represent 84% of the United States' costs, with salmonellosis and staphylococcal intoxication being the most economically important diseases (annually $4.0 billion and $1.5 billion, respectively). Other costly types of illnesses are toxoplasmosis ($445 million), listeriosis ($313 million), campylobacteriosis ($156 million), trichinosis ($144 million), Clostridium perfringens enteritis ($123 million), and E. coli infections including hemorrhagic colitis ($223 million). Botulism has a high cost per case ($322,200), but its total impact is only $87 million because relatively few cases occur (270). This is because the food industry has been able to introduce effective control measures. Salmonellosis, however, is much more widespread (2.9 million cases) and affects all sectors of the food industry.


2017 ◽  
Vol 46 (2) ◽  
pp. 315-337 ◽  
Author(s):  
Maik Kecinski ◽  
Kent D. Messer ◽  
Lauren Knapp ◽  
Yosef Shirazi

Oyster aquaculture has experienced tremendous growth in the United States over the past decade, but little is known about consumer preferences for oysters. This study analyzed preferences for oysters with varied combinations of brands, production locations, and production methods (aquaculture vs. wild-caught) using dichotomous choice, revealed preference economic field experiments. Results suggest significant and distinct differences in behavior between first-time and regular oyster consumers. While infrequent oyster consumers were drawn to oysters labeled as wild-caught, experienced oyster consumers preferred oysters raised via aquaculture. These findings will be valuable for growers and policymakers who invest in aquaculture to improve surrounding ecosystems.


2013 ◽  
Vol 27 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Kelly A. Barnett ◽  
A. Stanley Culpepper ◽  
Alan C. York ◽  
Lawrence E. Steckel

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic for cotton growers in the Southeast and Midsouth regions of the United States. Glufosinate can control GR Palmer amaranth, and growers are transitioning to glufosinate-based systems. Palmer amaranth must be small for consistently effective control by glufosinate. Because this weed grows rapidly, growers are not always timely with applications. With widespread resistance to acetolactate synthase-inhibiting herbicides, growers have few herbicide options to mix with glufosinate to improve control of larger weeds. In a field study using a WideStrike®cotton cultivar, we evaluated fluometuron at 140 to 1,120 g ai ha−1mixed with the ammonium salt of glufosinate at 485 g ae ha−1for control of GR Palmer amaranth 13 and 26 cm tall. Standard PRE- and POST-directed herbicides were included in the systems. Glufosinate alone injured the WideStrike® cotton less than 10%. Fluometuron increased injury up to 25% but did not adversely affect yield. Glufosinate controlled 13-cm Palmer amaranth at least 90%, and there was no improvement in weed control nor a cotton yield response to fluometuron mixed with glufosinate. Palmer amaranth 26 cm tall was controlled only 59% by glufosinate. Fluometuron mixed with glufosinate increased control of the larger weeds up to 28% and there was a trend for greater yields. However, delaying applications until weeds were 26 cm reduced yield 22% relative to timely application. Our results suggest fluometuron mixed with glufosinate may be of some benefit when attempting to control large Palmer amaranth. However, mixing fluometuron with glufosinate is not a substitute for a timely glufosinate application.


2020 ◽  
Vol 110 (6) ◽  
pp. 1147-1152 ◽  
Author(s):  
T. Hartman ◽  
B. Tharnish ◽  
J. Harbour ◽  
G. Y. Yuen ◽  
T. A. Jackson-Ziems

The bacterial pathogen Xanthomonas vasicola pv. vasculorum was first reported in the United States causing bacterial leaf streak on Nebraska corn (Zea mays) in 2016. The bacterium is also known to cause disease in sugarcane, grain sorghum, broom bamboo, and various palm species. The objective of this study was to identify alternative hosts for X. vasicola pv. vasculorum among plants commonly found in corn growing areas of the United States. In repeated greenhouse experiments, 53 species of plants found in the United States that had not been tested previously for susceptibility to X. vasicola pv. vasculorum were inoculated with the pathogen and monitored for symptom development. Eleven species in the family Poaceae exhibited symptoms: oat (Avena sativa), rice (Oryza sativa), orchardgrass (Dactylis glomerata), indiangrass (Sorghastrum nutans), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), timothy (Phleum pratense), sand bluestem (Andropogon hallii), green foxtail (Setaria viridis), bristly foxtail (Setaria verticillata), and johnsongrass (Sorghum halepense). Yellow nutsedge (Cyperus esculentus) in the Cyperaceae also was a symptomatic host. In addition, endophytic colonization by X. vasicola pv. vasculorum was found in three asymptomatic alternative hosts: downy brome (Bromus tectorum), tall fescue (Festuca arundinacea), and western wheatgrass (Pascopyum smithii). Experiments were also conducted in the field to determine the potential for alternative hosts to become infected by natural inoculum. Symptoms developed only in big bluestem and bristly foxtail in field experiments. These results suggest that infection of alternative hosts by X. vasicola pv. vasculorum can occur, but infection rates might be limited by environmental conditions.


1994 ◽  
Vol 34 (7) ◽  
pp. 1021 ◽  
Author(s):  
JE Hill ◽  
RJ Jr Smith ◽  
DE Bayer

Among temperate rice areas, the United States and Australia are most similar in climate and in the mechanisation of rice culture. Many weed problems, even weed species invading rice, are common to both countries; and the present technology for weed control as well as concern for the impact of these technologies to environmental quality, herbicide resistance, and other weed-related issues bear many similarities. Application of current, and any new, technologies to emerging issues in US rice weed control will therefore be directly relevant to rice production in Australia and all other temperate areas struggling with the same challenges. Weeds are a significant problem in temperate rice culture. In the United States, rice is mechanically direct-seeded, allowing weeds to germinate and establish with the crop. In the last 15 years weed growth and competition has been increased by the adoption of semi-dwarf cultivars, high N fertilisation, and, in water-seeded rice, shallow flooding. High rates, and often multiple applications, of herbicides have been necessary to maximise the yield potential of these cultural systems. Advances in cultural practices and herbicide technology have maintained, if not improved, weed control; but nearly 30 years of propanil use in the southern USA resulted in propanil-resistant barnyard grass Echinochloa crus-galli (L.) Beauv., and after 4 years of continuous use, bensulfuron resistance to 4 aquatic weed species was discovered in California. Although herbicides with different mechanisms of action are needed for alternation in resistance management strategies, fewer are likely to be available. Social and environmental concerns have slowed the development and registration of rice herbicides and increased the cost of controlling weeds. Water quality deterioration from ricefield tailwaters, drift to sensitive crops, the cost of renewing registration in aquatic systems, and weed resistance all forecast reduced herbicide use in rice. Neither cultural practices nor herbicides alone can solve weed problems in direct-seeded, mechanised rice culture. With fewer herbicides and a cultural system highly vulnerable to weed losses, integrated management strategies with better information on which to base weed control decisions will be needed to solve weed problems in temperate rice.


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