Core Ideas Cover crops can effectively suppress weeds after termination and up to early stage of crop growth. Use cover for season weed suppression did not affect grain yield, but improved yield vegetable crops. a single species provided similar that mixtures. There were differences in main management among studies evaluated suppression. are gaining importance as their use has numerous benefits including soil health, reduced erosion, Weeds most competitive with at growth stages, strategy...

Crop losses from weed interference have a significant effect on net returns for producers. Herein, potential corn yield loss because of across the primary corn-producing regions United States and Canada are documented. Yield-loss estimates were determined comparative, quantitative observations yields between nontreated treatments providing greater than 95% control in studies conducted 2007 to 2013. Researchers each state province provided data replicated, small-plot at least 3 up 10...

We conducted a previous systematic and meta‐analysis review that showed differences in results from studies evaluated the effectiveness of cover crops for weed suppression cropping systems; these were largely due to management approaches used growing crop main crop. The current provides quantitative on how practices influence impact suppression. observations 53 published 1990 2018. Cover biomass was inversely related amount ( r 2 = 0.67) density 0.64). In general, shows provided range...

Weeds are one of the most significant, and controllable, threats to crop production in North America. Monetary losses because reduced soybean yield decreased quality weed interference, as well costs controlling weeds, have a significant economic impact on net returns producers. Previous Weed Science Society America (WSSA) Loss Committee reports, chaired by Chandler (1984) Bridges (1992), provided snapshots comparative weeds across geographic regions crops within these after implementation...

Growing a crop in place of fallow may improve soil properties but result reduced water and yields semiarid regions. This study assessed the effect replacing no‐till winter wheat ( Triticum aestivum L.)–fallow with cover, forage, or grain crops on plant available (PAW), yield, quality, profitability over 5 yr, from 2007 to 2012. Plant at planting was most when period shortest (i.e., following crops) biomass production greatest. Winter spring lentil Lens culinaris Medik.) produced least...

Abstract Earlier reports have summarized crop yield losses throughout various North American regions if weeds were left uncontrolled. Offered here is a report from the current WSSA Weed Loss Committee on potential due to based data collected of United States and Canada. Dry bean loss estimates made by comparing dry in weedy control with plots that had >95% weed research studies conducted growing Canada over 10-year period (2007 2016). Results these field showed growers Idaho, Michigan,...

Abstract The widespread evolution of herbicide resistance in weed populations has become an increasing concern for no-tillage (NT) growers semiarid regions the U.S. Great Plains. Lack cost-effective and alternative new sites action further exacerbates problem herbicide-resistant (HR) weeds threatens long-term sustainability prevailing cropping systems region. A recent decline commodity prices costs to manage HR spurred research efforts build a strong rationale developing ecologically based...

Evolution of multiple herbicide resistance in Palmer amaranth across the United States is a serious challenge for its management. Recently, population (KCTR; Kansas Conservation Tillage Resistant) from long-term conservation tillage research project Kansas, States, was found uncontrolled by several commonly used herbicides. Importantly, this field did not have history repeated use some herbicides which KCTR showed lack control. The objectives study were to confirm evolution resistances and...

Abstract Yield losses due to weeds are a major threat wheat production and economic well-being of farmers in the United States Canada. The objective this Weed Science Society America (WSSA) Loss Committee report is provide estimates yield weeds. scientists provided both weedy (best management practices but no weed control practices) weed-free providing >90% control) average from replicated research trials winter spring 2007 2017. Winter loss ranged 2.9% 34.4%, with weighted (by...

Abstract Potato is the third most important staple food crop globally following rice and wheat. In United States, potato grown on approximately 410,000 ha with a farm-gate value of US$1,032 million. Canada, 134,000 US$235 The objective this manuscript, compiled by Weed Science Society America Loss Committee, was to estimate yield loss caused weed interference. data from weedy weed-free plots (or >95% control) obtained researchers working management in States Canada or published...

Abstract Double crops and cover can increase cropping intensity diversity, which are associated with productive, sustainable systems. However, adoption of remains low. A long‐term study a no‐till, sorghum [ Sorghum bicolor (L.) Moench]–soybean Glycine max Merr.]–wheat ( Triticum aestivum L.) rotation intensified double or was used to evaluate the effect fallow management nitrogen fertilizer applications on system productivity net returns. The experiment established near Manhattan, KS, in...

Field experiments were conducted at Ashland Bottoms in northeastern Kansas and Hays western 2001, 2002, 2003 to determine the response of soil microbial nematode communities different herbicides tillage practices under a glyphosate-resistant cropping system. Conventional herbicide treatments tank mixture cloransulam plus S -metolachlor sulfentrazone for soybean commercially available acetochlor atrazine corn. Glyphosate was applied 1.12 kg ai ha −1 when weeds 10 or 20 cm tall both corn...

A fast-spreading weed, kochia (Kochia scoparia), has developed resistance to the widely-used herbicide, glyphosate. Understanding relationship between occurrence glyphosate caused by multiple EPSPS gene copies and fitness may suggest a more effective way of controlling kochia. study was conducted assess cost compare susceptibility in populations at different life history stages, that is rate seed germination, increase plant height, days flowering, biomass accumulation maturity, fecundity....

Timing of weed emergence and seed persistence in the soil influence ability to implement timely effective control practices. Emergence patterns kochia populations were monitored 2010 2011 at sites Kansas, Colorado, Wyoming, Nebraska, South Dakota. Weekly observations initiated March continued until no new occurred. Seed was harvested from each site, placed into 100-seed mesh packets, buried depths 0, 2.5, 10 cm fall 2011. Packets exhumed 6-mo intervals over 2 yr. Viability seeds evaluated....

Reports of kochia control failure with glyphosate in western Kansas increased dramatically the years following confirmed presence glyphosate-resistant (GR) populations 2007. In this study, progeny from 8 16 geographically dispersed (seed collected 2010) were to be resistant by conducting whole-plant dose-response (in greenhouse and/or outdoor environments) and shikimate-accumulation assays. Additionally, relationship between 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy...

Palmer amaranth has evolved target and nontarget site resistance to protoporphyrinogen oxidase-inhibitor herbicides in the United States. Recently, a population (KCTR) from long-term conservation tillage study Kansas was found be resistant six sites of action, including PPO-inhibitors, even with this herbicide group being minimally used field. This research investigated level postemergence target- nontarget-site mechanism(s), efficacy pre-emergence chemistries. The greenhouse experiments...

WeedSOFT® is a decision support system that was developed to help farmers and consultants in Nebraska with the selection of optimal weed management strategies. evolved from HERB, bioeconomic model for soybean North Carolina. The program composed four independent modules, namely, ADVISOR, EnviroFX, MapVIEW, WeedVIEW. ADVISOR helps user select treatment based on maximum yield or net gain. EnviroFX MapVIEW provide environmentally relevant herbicide information county soil maps indicate...

Kochia ( scoparia L.) is a well‐adapted weed found throughout the semiarid Great Plains and has increased in concern because biotypes with resistance to numerous herbicide modes of action are present, thus reducing options for control. The objectives research were determine if cover crops growing during fallow phase no‐till winter wheat Triticum aestivum L.)–fallow cropping system could reduce kochia density biomass without subsequent yields. Five fall‐sown Austrian pea Pisum sativum ssp....

Overreliance on acetolactate synthase (ALS)‐inhibiting herbicides for weed control during the 1990s resulted in selection of ALS‐resistant shattercane [ Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet Davidse] biotypes Nebraska. The objective this study was to assess baseline presence ALS‐resistance 190 and 59 johnsongrass halepense Pers.] populations collected across northern Kansas, northwestern Missouri, southern Nebraska 2013. In 2014, a preliminary field experiment...

Abstract The objective of this WSSA Weed Loss Committee report is to provide quantitative data on the potential yield loss in sugar beet due weed interference from major growing areas United States and Canada. Researchers extension specialists who conducted research control Canada provided their regions. Specifically, were requested studies up 10 individual per calendar year over a 15-yr period between 2002 2017. Data collected indicated that if weeds are left uncontrolled under optimal...

Abstract Potential yield losses in grain sorghum due to weed interference based on quantitative data from the major sorghum-growing areas of United States are reported by WSSA Weed Loss Committee. scientists and extension specialists who researched control provided loss their region. Data were requested up 10 individual experiments per calendar year over yr between 2007 2016. Based summarized information, farmers Arkansas, Kansas, Missouri, Nebraska, South Dakota, Texas would potentially...

Abstract A field study was conducted from 2020 to 2023 at Kansas State University Agricultural Research Center near Hays, KS, understand the emergence dynamics and periodicity of glyphosate-resistant (GR) Palmer amaranth ( Amaranthus palmeri S. Watson) as influenced by cover crop (CC) residue residual herbicide in grain sorghum [ Sorghum bicolor (L.) Moench]. The site under a wheat Triticum aestivum L.)–sorghum–fallow rotation with natural seedbank GR A. . Treatments included (1)...

Recent interest in describing the spatial distribution of weeds and studying their association with site properties has increased use interpolation to estimate weed seedling density from spatially referenced data. In addition, farmers consultants adopting elements site-specific farming practices are using methods for mapping densities as well soil properties. This study was conducted compare performance four methods, namely inverse-distance weighting (IDW), ordinary point kriging (OPK),...

Studies were conducted to determine if altered absorption, translocation, or metabolism the basis for reduction in sulfonylurea herbicide efficacy on foxtail species when mesotrione was mixed with a herbicide. Green and yellow plants grown greenhouse treated at four-leaf stage 14 C-labeled nicosulfuron rimsulfuron, applied alone + atrazine. Absorption of greater green 7 d after treatment (DAT) alone, compared absorption mixing When 9% more translocated DAT, as combination Translocation...