Master of Science / Department of Agronomy / Dallas Peterson / Kochia (Kochia scoparia (L.) Schrad) is a troublesome and highly competitive weed in many cropping systems in the Great Plains region. It has traditionally been controlled using postemergence (POST) applications of glyphosate, however control is becoming inconsistent. Use of preemergence (PRE) herbicides may help to control kochia. Objectives of this research were to (1) Evaluate the efficacy of selected PRE herbicides in combination with POST applied glyphosate for controlling kochia in soybeans, (2) evaluate a kochia population (Norton) response to various rates of glyphosate compared to previously characterized highly susceptible (Syracuse) and moderately resistant (Ingalls) kochia populations, and (3) quantify the effects of herbicide rate, planting depth, soil pH, and soil type on corn, soybean, and grain sorghum tolerance to saflufenacil. Field studies showed that glyphosate applied alone did not always provide adequate season-long kochia control. In general, PRE herbicide treatments provided effective kochia control. These data suggest that a sequential herbicide program with a PRE herbicide treatment followed by POST glyphosate will provide the most consistent kochia control in soybeans and help minimize the risk of developing herbicide resistant kochia. Greenhouse studies confirmed great variability in kochia susceptibility to glyphosate across three different kochia populations. In general, as glyphosate rates increased, kochia control increased with all three populations. At the field use rate of glyphosate, the Syracuse kochia population was controlled 94% 21 days after treatment (DAT), whereas the Ingalls and Norton populations were controlled 26 and 41% respectively. Nonlinear regression analysis for each population indicated the glyphosate rate required to cause 50% visible control (GR50) was 1.6, 1.1, and 0.31 times the field use rate of 870 g ae/ha for the Ingalls, Norton, and Syracuse kochia populations. Greenhouse studies indicated that soil type had the greatest impact on saflufenacil injury to corn, soybeans, and sorghum, with crop injury consistently being greater on a fine sandy loam soil with 0.9% organic matter than a silt loam soil with 3.9% organic matter. Soil pH, saflufenacil rate, and seed depth also may influence the risk of crop injury from saflufenacil, but were less important than soil type.

Studies were conducted in 2009 and 2010 under field and growth room conditions to determine a) cultivar tolerance of soybean to preemergence (PRE) applications of saflufenacil and b) the biologically effective rate of saflufenacil/dimethenamid-p for control of annual weeds applied PRE alone and prior to an in-crop application of glyphosate. Environmental conditions following application influenced the amount of soybean injury caused by saflufenacil, as well as the rate of saflufenacil/dimethenamid-p required for the control of annual weeds. Increased soybean injury from saflufenacil was observed when soybean emergence was delayed due to cool, wet conditions following planting. Injury decreased with time; however, sensitive soybean cultivars were unable to fully recover from early season injury under adverse environmental conditions. OAC Hanover was the most sensitive cultivar in both field and hydroponic testing. With adequate moisture and above average temperatures in 2010, between 224 and 374 g a.i. ha-1 of saflufenacil/dimethenamid-p was required for 80% control of common ragweed, common lambsquarters, and green foxtail 4 weeks after treatment (WAT). In contrast, with below average temperatures and excessive moisture in 2009, between 528 and 613 g a.i. ha-1 of saflufenacil/dimethenamid-p was necessary for the same level of weed control. Pigweed species were least affected by environmental conditions after application with only 245 g a.i. ha-1 required for 80% control 4 WAT in both years. Excellent full season control of all weed species was achieved with saflufenacil/dimethenamid-p applied PRE followed by glyphosate postemergence (POST). However, there was no difference in yield when saflufenacil/dimethenamid-p was followed by glyphosate POST compared to a single glyphosate POST application. / BASF Canada

Field and greenhouse studies were conducted in 2007 and 2008 to evaluate the foliar efficacy of saflufenacil on horseweed (Conyza canadensis (L.) Cronq.). In the field, saflufenacil applied alone at the lowest rate (25 g/ha) resulted in less control than all other herbicide treatments that included saflufenacil. The addition of glyphosate to 25 g/ha of saflufenacil increased the level of control over either herbicide applied alone. However, the addition of glyphosate to 50 g/ha of saflufenacil or greater was not beneficial because saflufenacil alone provided at least 95% control. Overall, horseweed height at the time of herbicide application had very little effect on the efficacy of saflufenacil applied alone or in combination with glyphosate. Application variables can enhance the foliar activity of saflufenacil. In the greenhouse, saflufenacil combined with glyphosate provided greater control than saflufenacil applied alone on both glyphosate-susceptible and -resistant horseweed populations. Regardless of horseweed population or glyphosate, saflufenacil had greater activity when crop oil concentrate rather than nonionic surfactant was used as the adjuvant. Decreasing light level within 24 hours of herbicide application resulted in greater saflufenacil activity. Applying saflufenacil in a pH 5 spray solution resulted in greater activity than pH 7 or pH 9. Although effects from saflufenacil applied under different temperatures were evident in early timings, there were no lasting effects on the efficacy of saflufenacil. Saflufenacil had significant activity on both glyphosate-susceptible and -resistant horseweed. Under certain conditions when complete control of horseweed is not achieved, such as low application rates, large target weeds, and varying environmental conditions, application variables including glyphosate tank-mixtures, crop oil concentrate, low spray solution pH, and low light level may increase the level of horseweed control from saflufenacil.

Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2017-03-23T13:37:04Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_anderson_feijo.pdf: 1385026 bytes, checksum: 5f73bbd78d6f039beba48ed42c0c433c (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-03-27T20:47:58Z (GMT) No. of bitstreams: 2 dissertacao_anderson_feijo.pdf: 1385026 bytes, checksum: 5f73bbd78d6f039beba48ed42c0c433c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-27T20:47:58Z (GMT). No. of bitstreams: 2 dissertacao_anderson_feijo.pdf: 1385026 bytes, checksum: 5f73bbd78d6f039beba48ed42c0c433c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-09-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / No cultivo do arroz irrigado as plantas daninhas que apresentam maior importância são: o arroz daninho e capim-arroz. O controle químico é atualmente o principal método de controle destas plantas daninhas. A utilização de cultivares tolerantes aos imidazolinonas possibilita um controle seletivo. A mistura de herbicidas pode proporcionar inúmeras vantagens como redução das doses aplicadas e aumento do espectro de ação. Saflufenacil um herbicida relativamente novo apresenta potencial para ser aplicado em mistura com outros herbicidas. Além disso, ele é indicado para aplicação em pré-emergência com ação residual no solo. O objetivo deste estudo foi verificar a eficiência no controle de arroz daninho e capim-arroz; a seletividade ao arroz irrigado, com o uso de misturas em tanque entre imazapyr+imazapic e saflufenacil; avaliar as interações de misturas entre os dois herbicidas em plantas de arroz daninho, bem como, avaliar possíveis alterações no metabolismo antioxidante durante a germinação em função da aplicação de saflufenacil. Para atingir esses objetivos, foram conduzidos três experimentos; O experimento I foi realizado em campo, utilizou-se o cultivar Puitá INTA CL, os tratamentos foram compostos por aplicação isolada e em misturas de imazapyr+imazapic e saflufenacil. O experimento II foi realizado em casa de vegetação, onde foram aplicados imazapyr+imazapic e saflufenacil, isolados e em misturas, sendo que cada mistura foi constituída sempre por ao menos uma subdose dos herbicidas. Os resultados de controle, redução da estatura de plantas e matéria seca da parte aérea de arroz daninho, foram analisados pelo Método de Colby para verificar o efeito de interação. No experimento III, sementes de soja foram colocadas para germinar em presença de água ou solução herbicida de saflufenacil, e incubadas no escuro ou expostas à luz (fotoperíodo de 14h), seis dias após, avaliou-se as alterações no metabolismo antioxidante e quantificou-se o extravasamento de eletrólitos. Os resultados do experimento I mostraram que saflufenacil não interferiu no percentual de controle de imazapyr+imazapic em capim-arroz e arroz daninho, além de não acarretar perda de produtividade na cultura do arroz. A menor dose de imazapyr+imazapic (36,75+12,25 g e.a. ha-1), isolada e em mistura proporcionou baixo nível de controle destas duas plantas daninhas, reduzindo a produtividade. No experimento II foi constatado um maior número de misturas com efeito de aditividade na interação entre os dois herbicidas. Resultados do experimento III mostram que ocorreu um incremento na atividade da SOD na luz e no escuro em diferentes doses de saflufenacil, maior atividade da CAT na dose de 3,0 μM na luz e no escuro e incremento da APX com 3,0 μM na luz e 6,0 μM na luz e escuro. Os teores de H2O2 foram maiores com saflufenacil na presença de luz, MDA foi elevado apenas na dose de 6,0 μM sob luz. O maior extravasamento de eletrólitos foi observado nos tratamentos com saflufenacil expostos à luz. Os resultados mostram que saflufenacil pode ser utilizado em mistura com imazapyr+imazapic no arroz irrigado, podendo ampliar o espectro de controle de plantas daninhas da cultura sem causar perdas de produtividade. Na ausência de luz saflufenacil causa incremento na atividade do sistema antioxidante, mas não proporciona danos às membranas celulares. / In irrigated rice weeds with the greatest importance they are: weedy rice and barnyardgrass. Chemical control is currently the main method of control of these weeds. The use of cultivars tolerant to imidazolinones allows selective control. The mixture of herbicides can provide many advantages such as reduction of the amount applied and increased spectrum of action. Saflufenacil a relatively new herbicide has the potential to be applied in tank mixture with other herbicides. Moreover, it presents a recommendation for application in pre-emergence residual action in the soil. The objective of this study was to determine the effects on weedy rice control and barnyardgrass; and selectivity to rice by applying mixtures of imazapyr+imazapic with saflufenacil; evaluating the interactions between mixtures of two herbicides in weedy rice plants, as well as to assess possible changes in antioxidant metabolism during germination depending on the application saflufenacil. To achieve these goals, three experiments were conducted; The first experiment was carried out in the field, used the cultivar Puitá INTA CL, the treatments were applied alone and in mixtures of imazapyr + imazapic with saflufenacil. The second experiment was conducted in a greenhouse, where they were applied imazapyr+imazapic and saflufenacil, alone and in mixtures, each mixture was always consists of at least one sub-dose of herbicides. The results of control, reduced height and shoot dry mass of weedy rice were analyzed by Colby’s Method to check the effect of interaction. In the experiment III, soybean seeds were germinated in the presence of water or solution herbicide saflufenacil, and incubated in the dark or exposed to light (photoperiod of 14h), six days after was evaluated the changes in antioxidant metabolism and quantified the electrolyte leakage. The results of experiment I show that saflufenacil doesn’t interfere in the percentage of imazapyr + imazapic control in barnyardgrass and weedy rice, besides not causing loss of productivity in the rice crop. The lowest dose imazapic+imazapyr (36.75 + 12.25 g a.e. ha-1), alone and in mixture provided low level control of two weeds, reducing productivity. In experiment II was observed a greater number of mixtures additivity effect on the interaction between the two herbicides. Experiment III results show that there was an increase in the activity of SOD in the light and in the dark at different doses of saflufenacil, higher CAT activity at a dose of 3,0 μM in light and dark and increased APX with 3,0 μM in the light and 6,0 μM in light and dark. The H2O2 levels were higher with saflufenacil in the presence of light, MDA was raised only at the dose of 6,0 μM under light. The highest electrolyte leakage was observed in treatments with saflufenacil exposed to light. The results show that saflufenacil may be used in tank mixture with imazapyr+imazapic in irrigated rice, which can extend the weed control spectrum culture without causing productivity losses. In the absence of light saflufenacil causes increased activity of the antioxidant system, but doesn’t give damage to cell membranes.

Submitted by RONEI BEN null (roneiben@hotmail.com) on 2016-12-22T13:17:02Z No. of bitstreams: 1 dissertação.ronei ben Capa PRONTA .pdf: 1791714 bytes, checksum: aad07c8bd1c1e7a6d02afcc53b355511 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-03T19:39:25Z (GMT) No. of bitstreams: 1 ben_r_me_bot.pdf: 1791714 bytes, checksum: aad07c8bd1c1e7a6d02afcc53b355511 (MD5) / Made available in DSpace on 2017-01-03T19:39:25Z (GMT). No. of bitstreams: 1 ben_r_me_bot.pdf: 1791714 bytes, checksum: aad07c8bd1c1e7a6d02afcc53b355511 (MD5) Previous issue date: 2016-09-06 / O presente trabalho teve como objetivo avaliar a seletividade do herbicida saflufenacil para a cultura da soja. Para tanto, foram conduzidos quatro experimentos, sendo dois a campo e dois em casa-de-vegetação. Os dois experimentos à campo foram conduzidos nos meses de dezembro de 2014 à abril de 2015, no município de Nova MaringáMT. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições, as variedades de soja utilizadas foram a TMG 132 RR e BIOGENE 4377 RR. Os tratamentos foram compostos de glyphosate + saflufenacil nas doses de 1080+35 g ha-1 e 1080+49 g ha-1 e glyphosate (1080 g ha-1) aplicado aos 21, 14, 7 e 0 dias antes da semeadura da cultura, uma testemunha sem qualquer intervenção no manejo de plantas daninhas e uma testemunha que foi capinada durante todo o ciclo da cultura. As variáveis analisadas foram fitointoxicação (7, 14 e 28 dias após a emergência da cultura), altura de plantas, estande de plantas, número de vagens, número de grãos por vagem e a produtividade da cultura. Nos experimentos em casa de vegetação, a cultivar de soja utilizada foi a TMG 7062 IPRO. Em cada experimento, os tratamentos foram constituídos pela aplicação do herbicida saflufenacil associado com herbicida glyphosate em três épocas de aplicação em pré-semeadura das cultura e uma testemunha sem aplicação. Desta forma, os tratamentos foram arranjados em um esquema fatorial 3x2, onde 2 foram os tratamentos herbicidas, sendo duas doses de saflufenacil (35 e 49 g i.a. ha-1) e 3 épocas de aplicação dos herbicidas em pré-semeadura da cultura e uma testemunha (sem aplicação). As variáveis avaliadas foram fitointoxicação (14 e 28 D.A.E), altura de plantas (14 e 28 D.A.E), massa seca da parte aérea, clorofila a, b e carotenoides (14 e 28 D.A.E), extravasamento de eletrólitos (14 e 28 D.A.E) e lipoperóxidos (14 e 28 D.A.E). Nos experimentos a campo, o herbicida saflufenacil foi seletivo para a cultivar TMG 132 RR, independentemente da dose utilizada ou da época aplicada. Já para a cultivar BG 4377 RR, o herbicida saflufenacil causou redução na produtividade da cultura, independentemente da dose aplicada. Nos experimentos em casa de vegetação foi perceptível que o teor de argila influenciou diretamente, no poder de dano do herbicida saflufenacil, sendo que as maiores reduções de matéria seca da parte aérea foram observados quando, as plantas de soja foram conduzidas em solo arenoso. Entretanto outros experimentos devem ser conduzidos em solos arenosos a nível de campo para maiores conclusões.

Research was conducted in 2012 and 2013 to evaluate the use of saflufenacil in rice (Oryza sativa L.). Studies included a preemergence evaluation of different rates of saflufenacil in comparison to one rate of carfentrazone, a postemergence evaluation of saflufenacil at different rates and carfentrazone at one rate at different postemergence timings, an adjuvant evaluation to assess rice injury and weed control from different adjuvants when mixed with saflufenacil, a Clearfield program evaluation where saflufenacil was compared to other broadleaf herbicides in a Clearfield weed control program, and a cultivar tolerance evaluation where postemergence applications of saflufenacil were compared to carfentrazone on five different commercial rice cultivars.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed to evaluate control strategies of hairy fleabane (Conyza bonariensis) and also study the arthropods associated with this weed. For this, the work was divided into three chapters. The Chapter I aimed to evaluate the selectivity of herbicides with potential use to control hairy fleabane on forming species winter pastures, which are: oats, black oats, ryegrass and tetraploid ryegrass. Experiments were conducted under greenhouse conditions and evaluated the phytotoxicity of plants and production of shoot dry matter (SDM). The treatments were: 2,4-D amine (806 and 1612 g a.i. ha-1), metsulfuron-methyl (2.4 and 4.8 g a.i. ha-1); clorimuronethyl (20 and 40 g a.i. ha-1); imazetaphyr (350 and 700 g a.i. ha-1); diclosulam (16.8 and 33.6 g a.i. ha-1); saflufenacil (35 and 70 g a.i. ha-1) and flumioxazin (50 and 100 g a.i. ha-1), and the control. According to the results obtained, the selectivity of herbicides is species cultivated dependent and it is important to know the botanical composition of pasture before applying any herbicide. In Chapter II aimed to evaluate the combination effect of the herbicides glyphosate and saflufenacil at different doses on the control of hairy fleabane plants. The treatments consisted of doses that followed the logarithmic scale, and used the herbicides glyphosate and saflufenacil both applied alone and in mixture. Were evaluated the visual control and the SDM production of hairy fleabane plants. The results indicate that there is a synergistic relationship between the herbicide glyphosate and saflufenacil. Also, the association of saflufenacil and glyphosate is effective in controlling glyphosate-resistant hairy fleabane. The addition of the herbicide glyphosate with saflufenacil, besides improve control, prevents the occurrence of regrowth of hairy fleabane plants. In Chapter III, hairy fleabane plants were collected fortnightly in Boa Vista and Sao Vicente Incra South in order to evaluate the arthropods associated with this weed. The results show that hairy fleabane takes an important role as an alternative host of important pests of the soybean, such bugs and caterpillars, and too natural enemies. / Este trabalho teve como objetivo avaliar estratégias de controle de buva (Conyza bonariensis) e também estudar a artropodofauna associada a esta planta daninha. Para isso, o trabalho foi dividido em três capítulos. O capítulo I teve como objetivo avaliar a seletividade de herbicidas de uso potencial para o controle de buva sobre espécies formadoras de pastagens de inverno, sendo elas: aveia branca, aveia comum, azevém comum e azevem tetraplóide. Para isso, foram conduzidos experimentos em casa de vegetação e avaliada a fitointoxicação de plantas e a produção de massa de matéria seca da parte aérea (MMSPA). Os tratamentos avaliados foram: 2,4-D amina (806 e 1612 g i.a. ha-1); metsulfuron-methyl (2,4 e 4,8 g i.a. ha-1); clorimuron-ethyl (20 e 40 g i.a. ha-1); imazetaphyr (350 e 700 g i.a. ha-1); diclosulam (16,8 e 33,6 g i.a. ha-1); saflufenacil (35 e 70 g i.a. ha-1) e flumioxazin (50 e 100 g i.a. ha-1), além da testemunha. De acordo com os resultados obtidos, a seletividade dos herbicidas testados é dependente da espécie que está sendo cultivada, sendo importante se conhecer a composição botânica da pastagem antes de se aplicar qualquer herbicida. No capítulo II, objetivou-se avaliar o efeito da associação dos herbicidas glifosato e saflufenacil, em diferentes doses sobre o controle de plantas de buva. Os tratamentos foram compostos por doses que seguiram a escala logarítmica, sendo utilizados os herbicidas glifosato e saflufenacil tanto em aplicação isolada quanto em mistura. Foram avaliados o controle visual (%) e a produção de MMSPA das plantas de buva. Os resultados obtidos apontam que: existe uma relação sinérgica entre os herbicidas glifosato e saflufenacil; a associação de saflufenacil e glifosato é eficiente no controle de buva resistente ao herbicida glifosato e; a adição de glifosato ao herbicida saflufenacil, além de melhorar o controle, previne a ocorrência de rebrote de plantas de buva. No capítulo III, foram realizadas amostragens quinzenais de plantas de buva em Boa Vista do Incra e São Vicente do Sul afim de se avaliar a artropodofauna associada à esta planta daninha. Os resultados mostram que a buva assume importante função como hospedeiro alternativo de pragas importantes da cultura da soja, tais como espécies de percevejos e lagartas, assim como de inimigos naturais.

Doctor of Philosophy / Department of Agronomy / Phillip W. Stahlman / Saflufenacil is an experimental herbicide for control of broadleaf weeds in various crops including several herbicide resistant weed biotypes. Wheat is highly tolerant to preplant and preemergence applications of saflufenacil, but winter wheat growers prefer to apply herbicides postemergence (POST) in early spring. Objectives of this research were to (1) evaluate winter wheat and four common broadleaf weed species response to POST treatments of saflufenacil applied alone and in combination with bentazon or auxin herbicides at various rates both with and without adjuvants, and to (2) determine the possible mechanism(s) responsible for crop safening observed when saflufenacil is applied with 2,4-D amine or bentazon in winter wheat. Growth chamber, greenhouse, and field studies showed saflufenacil at a minimum rate of 25 g/ha controlled blue mustard and flixweed >85% when saflufenacil was applied alone or mixed with dicamba, 2,4-D amine, 2,4-D ester, or MCPA ester. Also, mixtures of bentazon with 13 g/ha of saflufenacil resulted in death of kochia, but increasingly higher rates of 2,4-D amine were needed to achieve 90% growth reduction when saflufenacil rates were decreased from 50 to 25 to 13 g/ha. In general, most of the saflufenacil combinations tested controlled henbit <85%. Leaf necrosis and stunting of winter wheat were reduced by tank mixing saflufenacil with dicamba, 2,4-D amine, or bentazon, but not with MCPA ester or 2,4-D ester. Including nonionic surfactant (NIS) in mixtures of saflufenacil plus 2,4-D amine resulted in significant wheat injury similar or greater than injury caused by saflufenacil plus NIS. Finally, 2,4-D amine enhanced saflufenacil absorption into winter wheat plants, whereas bentazon reduced absorption of saflufenacil. No more than 11% of applied saflufenacil translocated out of treated leaves to other plant parts when applied alone or when saflufenacil was mixed with 2,4-D amine or bentazon. Metabolism of saflufenacil by wheat plants was not affected by tank mixing with bentazon, but saflufenacil metabolism was slowed by mixing with 2,4-D amine. Overall, these studies indicate saflufenacil can potentially be used POST in wheat at an optimum rate of 25 g/ha plus 2,4-D amine or dicamba to effectively control blue mustard and flixweed.

Field and labratory studies were conducted to determine the efficacy of saflufenacil alone and with mixture partners for burndown. Field studies were conducted in 2009 and 2010 to evaluate saflufenacil in mixtures with glyphosate, glufosinate, or paraquat for control of glyphosate-resistant (GR) horseweed prior to planting cotton. Saflufenacil and saflufenacil mixtures were applied 7 days before planting (DBP). Saflufenacil at 25 and 50 g ai ha-1 in mixture with all three non-selective herbicides provided similar GR horseweed control when compared to the current standard of glyphosate plus dicamba. Control of GR horseweed was also not different at the 25 and 50 g ai ha-1 of saflufenacil across all mixtures from the standard of glyphosate plus dicamba. Laboratory studies were initiated to determine the uptake and translocation of saflufenacil alone and when mixed with glyphosate and paraquat. It was found that glyphosate plus saflufenacil had a greater absorption of saflufenacil at 2 and 8 HAT. By 24 HAT there were not any differences between the amount of saflufenacil absorbed into GR horseweed between treatments. Translocation data also confirmed that the majority of saflufenacil stayed in the treated leaf at 72 HAT.

The indeterminate nature of lentil (Lens culinaris Medik), in conjunction with adverse field conditions, can lead to varying degrees of maturity among plants at harvest. This variable maturity may have a negative influence on lentil production and can delay harvest. Desiccants are currently used to improve lentil crop dry-down. However, applying desiccants too early may result in reduced crop yield and quality, and also leave unacceptable herbicide residues in lentil seeds. In addition, only four herbicides (glyphosate, diquat, saflufenacil, and glufosinate) are registered as desiccants for lentil desiccation in Canada, which limits options for growers. Therefore, the objectives of this thesis were i) to determine the importance of desiccant application timing in affecting crop yield and quality, as well as herbicide residues and ii) to determine whether additional desiccants applied alone or tank-mixed with glyphosate provide better crop desiccation. Field trials were conducted at Saskatoon and Scott, Saskatchewan, from 2012 to 2014. In the application timing trial, glyphosate or saflufenacil alone, or glyphosate+saflufenacil generally decreased seed yield, thousand seed weight, and crop dry-down, and increased herbicide residue levels at earlier application timings. For example, when applied at 60% seed moisture, saflufenacil reduced yield and thousand seed weight by 22% and 10%, respectively, and resulted in glyphosate and saflufenacil residues greater than 2.0 and 0.03 ppm, respectively. Although there were no reductions in yield and thousand seed weight when desiccants were applied at 50% or 40% seed moisture, glyphosate residue exceeded 2.0 ppm. Application of desiccants at 20 or 30% seed moisture content had no effect on yield, thousand seed weight, or herbicide residues. These results indicate that desiccant application timing is critical, and should not be made before 30% seed moisture. In a second study, glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants and provided optimal crop dry-down without reducing yield and thousand seed weight, and effectively reduced glyphosate residue. The other herbicides tested (pyraflufen-ethyl and flumioxazin) were found to be poor options for growers as they had sub-optimal crop desiccation and did not affect glyphosate residue.