Paraquat and diquat were effective against weeds immediately at 3 DAT. Glyphosate, sulfosate, and glufosinate exhibited activity against the weeds at 7 to 10 DAT. Paraquat provided the most complete weed control of most weeds at 10 to 16 DAT. Most of the diquat treated weed recovered and exhibited regrowth after 22 DAT. Glufosinate did not provide adequate control of most weeds at 22 DAT similar to diquat. Glyphosate and sulfosate were nearly equivalent at 0.50 and 2.0 lb AI/A against most weeds at most of the rating dates.

No description available.

No description available.

No description available.

Lack of technical knowledge and proper soybean cultivars are barriers for organic farmers to take advantage of increased organic soybean demand in Manitoba from domestic and international markets. The objective of the present study was to evaluate the performance of 12 early season non-GM food grade soybean cultivars under organic management in southern Manitoba. Cultivars were seeded on four organic farms and one transition to organic farm in southern Manitoba in 2014 and 2015. The mean cultivar yield ranged from 1384 to 1807 kg ha-1, with a mean of 1536 kg ha-1. Cultivars ‘Savanna’ and ‘Toma’ were high performers, but exhibited low stability across sites. Partial Least Squares Regression Analysis indicated that soybean mature height, and biomass at R5 positively contributed to final grain yield. Early height positively contributed to biomass at R5 but negatively affected final grain yield. Soil nitrate content negatively contributed to final grain yield. Weed competitiveness was of particular interest in this study. Contrary to previous reports, cultivars that exhibited early season vigour often resulted in lower yields, biomass accumulation, and increased weed presence as compared to other cultivars. / October 2016

Master of Science / Department of Agronomy / J.A. Dille / The availability of ALS-inhibitor herbicide-resistant grain sorghum hybrids will provide an opportunity to control grass weeds post-emergence with the ALS-inhibiting herbicide nicosulfuron (Zest[superscript]TM). More information on impact of grass weeds on sorghum yield are needed to optimize the application of nicosulfuron. The research objectives were to evaluate the impact of time of grass weed removal on grain sorghum yield when grown in different crop row spacing and seeding rates and to determine the critical duration of grass weed competition. Field studies were conducted in 2014 and 2015 at the KSU Agricultural Research Center at Hays, KS and the KSU Department of Agronomy Research Farm near Manhattan, KS. Four main treatments were grain sorghum row spacing of 25 and 76 cm at Hays or 20 and 76 cm at Manhattan, and two seeding rates of 125,000 and 150,000 seed ha⁻¹. Within each main plot, seven treatments were established including: weed-free all season using pre-emergence herbicides, weed-free all season by hand, weedy for 2, 3, 4, and 5 weeks after crop emergence in 2014 or weedy for 2, 4, 6, and 8 weeks after crop emergence in 2015, and weedy all season. The main grass weeds were giant, green, and yellow foxtail species, large crabgrass, and barnyardgrass. Grass weed biomass increased through the season at both locations in 2014 and in Manhattan in 2015. Hays 2014 grain sorghum aboveground stem and leaf biomass across row spacing and seeding rates decreased as weed removal time was delayed through the growing season. Grain sorghum yield decreased with increasing duration of grass weed competition in both years in Manhattan and in 2014 at Hays. Yield loss reached 5% at 2.3 to 25 weeks after sorghum emergence in narrow row spacing and 3.3 to 6.3 weeks after sorghum emergence in wide row spacing, depending on location, demonstrating that removing grass weed competition during these time frames will prevent more than 5% loss in grain sorghum yields.

A utilização de herbicidas para o manejo químico de plantas daninhas é um dos métodos mais eficientes de controle utilizados atualmente. Entretanto, herbicidas considerados seletivos às culturas podem interferir no desenvolvimento vegetativo das plantas ou na produtividade final. Dessa forma, este estudo teve como objetivo avaliar o efeito dos quatro principais herbicidas utilizados na cultura do algodoeiro atualmente, dois utilizados em pré-emergência da cultura e plantas daninhas (Clomazone e Diuron) e dois utilizados em pós-emergência da cultura e plantas daninhas (Trifloxysulfuron-sodium e Pyrithiobac-sodium) nas cultivares Fibermax 966, DeltaOpal e Aroeira, principais cultivares utilizadas comercialmente, com baixo, médio e alto vigor vegetativo, respectivamente. O delineamento experimental adotado foi de blocos casualizados, com 4 repetições. Cada um dos blocos constou de 9 sub-parcelas para cada uma das 3 cultivares, totalizando 36 sub-parcelas. Nas sub-parcelas de cada cultivar foram distribuídos oito tratamentos herbicidas, além da testemunha, sendo esta mantida livre de plantas daninhas durante todo o ciclo da cultura através de capinas manuais. Foram avaliados os principais fatores de desenvolvimento das plantas de algodoeiro como altura de plantas, Índice de Área foliar (IAF), massa seca de folha e ramos, produtividade, massa de capulhos, germinação de sementes e qualidade da fibra. Tanto para os herbicidas pré-emergentes, como para os pós-emergentes, foram verificadas injúrias nas plantas de algodoeiro, principalmente nos tratamentos com maior dosagem (Diuron na dose de 2,0 kg ia/ha, Clomazone na dose de 600 g ia/ha, Trifloxysulfuronsodium na dose de 7.5g ia g/ha e Pyrithiobac-sodium na dose de 140g ia/ha), entretanto, estas foram temporárias, desaparecendo nas avaliações posteriores. Em relação ao efeito destas injúrias no desenvolvimento vegetativo, a cultivar Fibermax 966 apresentou redução no acúmulo de massa seca e IAF, ambos na segunda avaliação para os tratamentos de pós-emergentes na maior dose, entretanto, esta diminuição de crescimento não proporcionou efeito negativo na produtividade final, massa de capulhos, germinação ou qualidade da fibra. Para as demais cultivares, os tratamentos herbicidas pós-emergentes não causaram nenhuma redução no desenvolvimento vegetativo quando comparados com a testemunha, tão pouco para as características finais como produtividade e qualidade de fibra. Para os tratamentos herbicidas em pré-emergência, o herbicida Diuron na dose de 2,0 kg ia/ha causou as maiores cloroses nas cultivares analisadas, além de levar a um menor acúmulo de massa seca e produtividade final para a cultivar Aroeira, quando comparada ao tratamento com Clomazone. Para as demais cultivares, não foram verificados quaisquer efeitos em relação ao desenvolvimento vegetativo, produtividade final ou qualidade da fibra produzida. / The use of herbicides for weed chemical management is one of the most efficient methods used nowadays. However, herbicides considered selective to the crop can cause some problems to the vegetative development or to the final yield. This way, the study aimed to evaluate the effect of four of the main herbicides used in the cotton crop, two of them used as pre-emergent of the crop and weeds (Clomazone and Diuron) and two used as post-emergent of the crop and weeds (Trifloxysulfuron-sodium e Pyrithiobac-sodium) in the varieties Fibermax 966, DeltaOpal and Aroeira, the main varieties commercially grown, with low, medium and high vegetative development. The experimental design used was the randomized blocks, with 4 replications. Each one of the blocks had 9 sup-plots to each variety, with a final number of 36 sub-plots. In the subplots of each variety there were 8 herbicides treatments plus the control treatment, this one left without weed interference along all the crop development, using manual weed control. The main features evaluated were plants height, Leaf Area Index (LAI), dry matter, yield, balls weight, seed germination and fiber quality. For both, the pre-emergent herbicide treatments, and postemergent treatments, there were injuries in the cotton plants, mainly to the treatments with highest doses (Diuron 2,0 kg ia/ha, Clomazone 600 g ia/ha, Trifloxysulfuron-sodium 7.5g ia g/ha and Pyrithiobac-sodium 140g ia/ha), however, these injuries were temporary and were not present in future evaluations. Regarding the effect of the injuries to the vegetative development, the cultivar Fibermax 966 showed Leaf Area Index and dry matter reduction in the post-emergent treatments, both in the second evaluation to the treatments in the highest dose. This decrease in plant development did not impact final yield, balls weight, seed germination or fiber quality. To the other varieties, the post-emergent herbicide treatments did not lead any vegetative development reduction when compared to the control treatment, neither to the final characteristics as yield, fiber quality and seed germination. Para os tratamentos herbicidas em pré-emergência, o herbicida Diuron na maior dose causou as maiores cloroses nas cultivares analisadas, além de levar a um menor acúmulo de massa seca e produtividade final para a cultivar Aroeira, quando comparada ao tratamento com Clomazone. Para as demais cultivares, não foram verificados quaisquer efeitos em relação ao desenvolvimento vegetativo, produtividade final ou qualidade da fibra produzida. For the pre-emergent herbicide treatments, Diuron in the highest dose caused greater damage to the different materials, leading to dry matter reduction and final yield for the cultivar Aroeira, when compared to the Clomazone treatment. For the other cultivars, the treatment did not present any effects in plants development, final yield or fiber quality.

A utilização de herbicidas para o manejo químico de plantas daninhas é um dos métodos mais eficientes de controle utilizados atualmente. Entretanto, herbicidas considerados seletivos às culturas podem interferir no desenvolvimento vegetativo das plantas ou na produtividade final. Dessa forma, este estudo teve como objetivo avaliar o efeito dos quatro principais herbicidas utilizados na cultura do algodoeiro atualmente, dois utilizados em pré-emergência da cultura e plantas daninhas (Clomazone e Diuron) e dois utilizados em pós-emergência da cultura e plantas daninhas (Trifloxysulfuron-sodium e Pyrithiobac-sodium) nas cultivares Fibermax 966, DeltaOpal e Aroeira, principais cultivares utilizadas comercialmente, com baixo, médio e alto vigor vegetativo, respectivamente. O delineamento experimental adotado foi de blocos casualizados, com 4 repetições. Cada um dos blocos constou de 9 sub-parcelas para cada uma das 3 cultivares, totalizando 36 sub-parcelas. Nas sub-parcelas de cada cultivar foram distribuídos oito tratamentos herbicidas, além da testemunha, sendo esta mantida livre de plantas daninhas durante todo o ciclo da cultura através de capinas manuais. Foram avaliados os principais fatores de desenvolvimento das plantas de algodoeiro como altura de plantas, Índice de Área foliar (IAF), massa seca de folha e ramos, produtividade, massa de capulhos, germinação de sementes e qualidade da fibra. Tanto para os herbicidas pré-emergentes, como para os pós-emergentes, foram verificadas injúrias nas plantas de algodoeiro, principalmente nos tratamentos com maior dosagem (Diuron na dose de 2,0 kg ia/ha, Clomazone na dose de 600 g ia/ha, Trifloxysulfuronsodium na dose de 7.5g ia g/ha e Pyrithiobac-sodium na dose de 140g ia/ha), entretanto, estas foram temporárias, desaparecendo nas avaliações posteriores. Em relação ao efeito destas injúrias no desenvolvimento vegetativo, a cultivar Fibermax 966 apresentou redução no acúmulo de massa seca e IAF, ambos na segunda avaliação para os tratamentos de pós-emergentes na maior dose, entretanto, esta diminuição de crescimento não proporcionou efeito negativo na produtividade final, massa de capulhos, germinação ou qualidade da fibra. Para as demais cultivares, os tratamentos herbicidas pós-emergentes não causaram nenhuma redução no desenvolvimento vegetativo quando comparados com a testemunha, tão pouco para as características finais como produtividade e qualidade de fibra. Para os tratamentos herbicidas em pré-emergência, o herbicida Diuron na dose de 2,0 kg ia/ha causou as maiores cloroses nas cultivares analisadas, além de levar a um menor acúmulo de massa seca e produtividade final para a cultivar Aroeira, quando comparada ao tratamento com Clomazone. Para as demais cultivares, não foram verificados quaisquer efeitos em relação ao desenvolvimento vegetativo, produtividade final ou qualidade da fibra produzida. / The use of herbicides for weed chemical management is one of the most efficient methods used nowadays. However, herbicides considered selective to the crop can cause some problems to the vegetative development or to the final yield. This way, the study aimed to evaluate the effect of four of the main herbicides used in the cotton crop, two of them used as pre-emergent of the crop and weeds (Clomazone and Diuron) and two used as post-emergent of the crop and weeds (Trifloxysulfuron-sodium e Pyrithiobac-sodium) in the varieties Fibermax 966, DeltaOpal and Aroeira, the main varieties commercially grown, with low, medium and high vegetative development. The experimental design used was the randomized blocks, with 4 replications. Each one of the blocks had 9 sup-plots to each variety, with a final number of 36 sub-plots. In the subplots of each variety there were 8 herbicides treatments plus the control treatment, this one left without weed interference along all the crop development, using manual weed control. The main features evaluated were plants height, Leaf Area Index (LAI), dry matter, yield, balls weight, seed germination and fiber quality. For both, the pre-emergent herbicide treatments, and postemergent treatments, there were injuries in the cotton plants, mainly to the treatments with highest doses (Diuron 2,0 kg ia/ha, Clomazone 600 g ia/ha, Trifloxysulfuron-sodium 7.5g ia g/ha and Pyrithiobac-sodium 140g ia/ha), however, these injuries were temporary and were not present in future evaluations. Regarding the effect of the injuries to the vegetative development, the cultivar Fibermax 966 showed Leaf Area Index and dry matter reduction in the post-emergent treatments, both in the second evaluation to the treatments in the highest dose. This decrease in plant development did not impact final yield, balls weight, seed germination or fiber quality. To the other varieties, the post-emergent herbicide treatments did not lead any vegetative development reduction when compared to the control treatment, neither to the final characteristics as yield, fiber quality and seed germination. Para os tratamentos herbicidas em pré-emergência, o herbicida Diuron na maior dose causou as maiores cloroses nas cultivares analisadas, além de levar a um menor acúmulo de massa seca e produtividade final para a cultivar Aroeira, quando comparada ao tratamento com Clomazone. Para as demais cultivares, não foram verificados quaisquer efeitos em relação ao desenvolvimento vegetativo, produtividade final ou qualidade da fibra produzida. For the pre-emergent herbicide treatments, Diuron in the highest dose caused greater damage to the different materials, leading to dry matter reduction and final yield for the cultivar Aroeira, when compared to the Clomazone treatment. For the other cultivars, the treatment did not present any effects in plants development, final yield or fiber quality.

Carduus nutans L., commonly called nodding thistle or musk thistle, has been in the United States for over 50 years; however, it was not until the early 1940's that it was identified in Kentucky. It was first identified in Kentucky in Warren County, and by 1970 had spread to 88 of the 120 counties in Kentucky. The thistle is present in all regions of the state, but most of the counties not having the thistle are located in the mountainous region of Eastern Kentucky. The thistle plant has a fleshy tap-root which is characteristically hollow near the soil surface. Flowering is determinate and the flowers vary in color from a deep pink at opening to near white at maturity. The plant is a prolific seed producer and may grow to a height of over eight feet in favorable growing conditions. In Central Kentucky, nodding thistle seeds are disseminated from June through August. The seeds are about three millimeters long and vary in color from gray to straw-brown at maturity. There appears to be a minimum eight-week dormancy period before the seeds will germinate. Ninety percent germination was obtained using one-year-old seeds. After emergence, plants enter the rosette stage in which they over-winter. Rosettes may reach four feet in diameter prior to bolting. Bolting occurs between March and August, and flowering begins in mid-May and continues through August. Nodding thistle plants in the study produced up to 561 heads per plant, and up to 1200 seeds per head. Individual plants produced from 200 to over 160,000 seeds. Nodding thistle plants in Central Kentucky may act as summer annuals, winter annuals, or biennials.

Johnsongrass (Sorghum halepense) competition in soybeans (Glycine max) has adverse effects on soybean yields. Profitable soybean production in Kentucky and the Southeastern United States has depended upon good, cost effective johnsongrass control. Several herbicides have been developed to control johnsongrass in soybeans. Four of these recently developed compounds were imazaquin (2-[4,5-dihydro-4-methy1-4- (1-methyl-ethyl)-5-oxo-1H-imidazo1-2-y1]-3-quino1inecarboxy1ic acid), imazethapyr (+/-)-2-C4,5-dihydro-4-methy1-4-(1-methy. lethyl)-5-oxo-IH-imidazol-2-y1)-5-ethy1-3-pyridinecarboxylic acid, quizalofop 2-[4-[(6-chloro-2-quinoxalinyl) oxylphenoxyjpropaonic acid,ethyl ester, and analog of quizalofop (DPX Y6202-31). Field experiments were conducted in 1986 to evaluate (a) the effectiveness of imazaquin and imazethapyr preplant incorporated, postemergence, or in combination with pendimethalin [N-(1-ethylpropy1)-3,4-dimethy1-2.6-dinitrobenzenamine], and (b) herbicide antagonism with fluazifop[butyl(R)-2-(4-[(5- trifluoromethy 1 ) - 2-pyridinl] oxy] phenoxy] propanoate], quizalofop, sethoxydim [2-[1-(ethoxyimino)butyl] -5-(2- (rthylthio)propy1]-3-hydroxy-2-cyclohexen-l-one, fenoxaprop [(+/-)-2-[4-((6-chloro-2-benzoxa-zoly) oxy]phenoxy]propanoic acid], and DPX-Y6202-31, in combination with imazaquin, bentazon [3-(1-methylethyl)-(ih)-2,1,3, benzothiadiazin- 4(3h)-one 2,2-dioxide], acifluorfen [5-[2-chloro-4(trifluoromethyl) phenoxy]-2-nitrobenzoic acid], and chlorimuron [3-(3,4-dichloropheny1)-1-methoxy-1-methylurea and Ethyl 2--[[[[(4-chloro-6-methoxy-pyrimidin-2-yl)amino)-carbonyl] amino]sulfonyl]binzoate], for johnsongrass control in soybeans. Imazaquin was applied preplant incorporated, tankmixed with pendimethalin and imazethapyr. Imazethapyr was applied preplant incorporated and postemergence with surfactant at equal rates. DPX-Y6202-31 was applied postemergence at four different rates, and in tankmix combinations with chlorimuron, acifluorfen, bentazon, and imazaquin, with surfactant or crop oil contrate. Quizalofop was applied postemergence at tour use rates.