Rates Of Isoxaflutole Research Articles

Phytotoxic Activity of Oil Palm Frond Mulch in Combination with Selected Pre-Emergence Herbicide

The combination of mulch and herbicide is a promising method for weed control which could reduce the frequency of hand weeding. This study was conducted to evaluate the phytotoxic effects of Elaeis guneensis var. tenera (oil palm) frond (OPF) mulch in combination with several pre emergence herbicides on the inhibition of goosegrass (Eleusine indica (L.) Gaertn), slender cyperus (Cyperus distans L.f.) and coat buttons (Tridax procumbens (L.)) under greenhouse conditions. Three rates of dinoterb, oxyfluorfen, and isoxaflutole were respectively, applied with or without OPF mulch at 3.5 t ha−1. The results showed that the weed inhibition provided by the dinoterb-treated OPF mulch (60 to 100%) was greater than dinoterb (0 to 50%) or OPF mulch (0 to 60%) applied alone across all the application rates and bioassay species. The oxyfluorfen-treated OPF mulch also gave greater inhibition (70 to 90%) of T. procumbens than those provided by oxyfluorfen (20 to 40%) or the OPF mulch alone (55 to 60%). However, an increase in inhibition of C. distans and E. indica was only evident at a low rate of oxyfluorfen when combined the OPF mulch. Weed inhibition was noted with increasing rates of isoxaflutole alone but the isoxaflutole-treated OPF mulch did not lead to further inhibition of weeds except for T. procumbens. These results suggest that the phytotoxicity of OPF mulch in combination with herbicides are dependent on weed species, herbicides, and application rates, with dinoterb being the most compatible with OPF mulch when combined

Annual weed management in isoxaflutole-resistant soybean using a two-pass weed control strategy

AbstractTransgenic crops are being developed with herbicide resistance traits to expand innovative weed management solutions for crop producers. Soybean with traits that confer resistance to the hydroxyphenylpyruvate dioxygenase herbicide isoxaflutole is under development and will provide a novel herbicide mode of action for weed management in soybean. Ten field experiments were conducted over 2 years (2017 and 2018) on five soil textures with isoxaflutole-resistant soybean to evaluate annual weed control using one- and two-pass herbicide programs. The one-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, at a low rate (52.5 + 210 g ai ha−1), medium rate (79 + 316 g ai ha−1), and high rate (105 + 420 g ai ha−1); and glyphosate applied early postemergence (EPOST) or late postemergence (LPOST). The two-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, followed by glyphosate applied LPOST, and glyphosate applied EPOST followed by LPOST. At 4 weeks after the LPOST application, control of common lambsquarters, pigweed species, common ragweed, and velvetleaf was variable at 25% to 69%, 49% to 86%, and 71% to 95% at the low, medium, and high rates of isoxaflutole plus metribuzin, respectively. Isoxaflutole plus metribuzin at the low, medium, and high rates controlled grass species evaluated (i.e., barnyardgrass, foxtail, crabgrass, and witchgrass) 85% to 97%, 75% to 99%, and 86% to 100%, respectively. All two-pass weed management programs provided 98% to 100% control of all species. Weed control improved as the rate of isoxaflutole plus metribuzin increased. Two-pass programs provided excellent, full-season annual grass and broadleaf weed control in isoxaflutole-resistant soybean.

Influence of nitrogen fertilization and isoxaflutole on the nodulation of chickpea (Cicer arietinum)

The effects of soil nitrate and the herbicide, isoxaflutole, on chickpea nodulation were examined in a glasshouse experiment. The treatments consisted of one isoxaflutole‐tolerant and one isoxaflutole‐sensitive chickpea cultivar, five nitrate concentrations (0, 0.75, 1.5, 3.0, and 6.0 mmol L−1), and three herbicide rates (0, 75 [the recommended rate], and 300 g ha−1). The sensitive cultivar was more susceptible to isoxaflutole damage with an increasing herbicide rate and nitrate concentration, compared with the tolerant cultivar. Isoxaflutole at the recommended rate reduced the nodule dry weight of the sensitive cultivar by 51% and by 33% in the tolerant cultivar. The nodule dry weight of the sensitive cultivar was reduced by 28%, 40%, 64%, and 76% with the addition of the 0.75, 1.5, 3.0, and 6.0 mmol L−1 nitrate concentrations, respectively. In comparison, the nodule dry weight of the tolerant cultivar was reduced by 50% and 79% at the 3.0 and 6.0 mmol L−1 nitrate concentrations, respectively. In addition, the level of damage from increasing rates of isoxaflutole increased with the highest nitrate concentrations of 3.0 and 6.0 mmol L−1, regardless of the cultivar. Isoxaflutole at the recommended application rate had a detrimental effect on the nodulation of both chickpea cultivars, but the isoxaflutole‐tolerant cultivar suffered less injury than the sensitive one in relation to some growth parameters. The damage to chickpea from the recommended rate of isoxaflutole also increased with soils of higher nitrate content.

The Effects of Temperature and Soil Moisture on Chickpea (Cicer arietinum L.) Genotype Sensitivity to Isoxaflutole

AbstractIsoxaflutole at 75 g ai ha−1 is registered in Australia for the control of several broadleaf weeds in chickpea (Cicer arietinum L.). Although isoxaflutole provides satisfactory control of problematic weeds, under certain conditions crop injury can occur. Higher air temperature and moisture content of soil are reported to affect the metabolism of soil applied herbicide. Controlled environment experiments were used to determine the tolerance of chickpea to isoxaflutole under a range of temperature and soil moisture levels. For the soil moisture study, the variables examined were two desi chickpea genotypes (Kyabra as a tolerant cultivar and Yorker as a sensitive cultivar), three soil moisture levels [50 % field capacity (FC), 75 % FC and FC] with three herbicide rates [0, 75 (recommended rate) and 300 g ai ha−1]. For the temperature by soil moisture study, the variables examined were two other desi chickpea genotypes (97039‐1275 as a tolerant line and 91025‐3021 as a sensitive line), three temperature regimes (20/5, 30/15 and 35/25 °C), two soil moisture conditions (50 % FC and FC) with the same three herbicide rates. The results demonstrated that the chickpea genotypes exhibited differential tolerance to isoxaflutole, but that differences in response were affected by rate, temperature and soil moisture. Increasing temperature and soil moisture content made the susceptible chickpea genotype more vulnerable to isoxaflutole damage. Injury to the susceptible genotype in terms of increased leaf chlorosis and reduction in shoot height and dry matter production increased as soil moisture increased from 50 % FC to FC and temperature increased from 20/5 to 35/25 °C. Overall damage of the sensitive genotype from increasing rates of isoxaflutole also increased when soil moisture content increased from 50 % FC to FC within the fixed temperature regime of 30/15 °C. The sensitivity of chickpea to isoxaflutole depends on existing temperature and moisture content and the chances of crop damage were enhanced with increasing temperature and moisture levels.

Selective Nimblewill (Muhlenbergia schreberi) Control in Cool-Season Turfgrass

Isoxaflutole and mesotrione have been used to control creeping bentgrass in cool season turf, these experiments evaluate these two products for selective nimblewill control. Three experiments were conducted in Virginia and Tennessee to evaluate selective control options for nimblewill in cool-season turfgrass. Single applications of isoxaflutole control nimblewill more effectively than single applications of mesotrione. Nimblewill control 8 wk after initial treatment (WAIT) increased as mesotrione rates increased from 28 to 280 g ai/ha, and isoxaflutole rates increased from 28 to 168 g/ha. Isoxaflutole at 84 and 168 g/ha were the only single application treatments that controlled nimblewill greater than 80% 8 WAIT. However, sequential applications of isoxaflutole and mesotrione at 28 g/ha, 10 d apart controlled nimblewill 94 and 80%, respectively 8 WAIT. Triclopyr and fenoxaprop-p did not effectively control nimblewill and caused unacceptable turfgrass injury. Long-term control was not evaluated in these studies. However, it was concluded that isoxaflutole and mesotrione at appropriate rates and applied in sequence selectively control nimblewill without harming desirable turf.

Effect of Planting Depth and Isoxaflutole Rate on Corn Injury in Nebraska

Field experiments were conducted at five sites in Nebraska in 2000 and 2001 to determine the effect of planting depth and isoxaflutole rate on the response of an isoxaflutole-sensitive corn hybrid, ‘Pioneer 33-G’ across variable environments. Corn was planted at depths of 2.5 and 5.0 cm, and isoxaflutole was applied PRE at the recommended (1×) and twice the recommended (2×) rate. The effects of planting depth and herbicide rate on injury varied considerably across site–years. When injury was evident, it was generally greater at the high rate of isoxaflutole (2×) and at the shallow planting depth (2.5 cm). In most site–years, corn recovered from early season injury, and yields were not reduced, except at Scottsbluff, NE, and North Platte, NE, where soils were lower in organic matter and higher in pH. Isoxaflutole rates should be carefully selected for soils with low organic matter and high pH.Nomenclature: Isoxaflutole, corn, Zea mays L

Phytotoxic response and yield of chickpea (Cicer arietinum) genotypes with pre-emergence application of isoxaflutole

Balance® (75% a.i. isoxaflutole) at 100 g/ha is registered in Australia for the control of several broadleaf weeds in chickpea. Polyhouse and field experiments were carried out to examine the tolerance of chickpea genotypes to isoxaflutole. Seven rates of isoxaflutole [0, 18.75, 37.5, 75 (recommended rate), 150, 300 and 600 g a.i./ha] were applied to 20 genotypes in the first polyhouse experiment while in the second experiment, 16 genotypes were tested. In the field, six genotypes were treated with five herbicide rates (0, 37.5, 75, 150 and 300 g a.i./ha). There was a strong dose response in the polyhouse experiments in visual injury ratings, plant height, and shoot and root dry weight. In general, there was less herbicide injury to the kabuli genotypes than in the desi chickpea genotypes. Chickpea genotypes Yorker, Howzat, Amethyst, Gully, 91025-3021, Jimbour, S 95425 and FLIP 94-92C exhibited higher overall mean injury rating in experiment 1. Among these genotypes, shoot dry matter was reduced significantly in Amethyst, Jimbour, 91025-3021 and S 95425. Root dry matter in Amethyst, Jimbour, Yorker, 91025-3021 and S 95425 was also reduced significantly. Height was reduced significantly in all of the above eight genotypes. Although there was less overall injury level in the second polyhouse experiment, which was at lower temperatures, Howzat, Yorker, 91025-3021, FLIP 94-92C and S 95425 again recorded high overall mean injury ratings and should be regarded as more susceptible to isoxaflutole than the other strains. In comparison, 97039-1275 and Kyabra recorded very minor injury symptoms in all the experiments and can be regarded as the most tolerant. The herbicide injury to the genotypes in the field was less than in the polyhouse although Yorker and 91025-3021 showed injury symptoms at early stages of growth. The injury symptoms were temporary and did not produce significant effects on the overall crop growth and yield. It is suggested that plant breeding programs take into account the relative susceptibility of new chickpea genotypes to isoxaflutole.

Influência do período de restrição hídrica na atividade residual de isoxaflutole no solo

O objetivo deste trabalho foi estudar a atividade residual do isoxaflutole (IFT) no controle de Brachiaria decumbens sob diferentes períodos de seca, após a aplicação do herbicida, em dois solos. Para isso, foram realizados seis ensaios simultâneos, sendo utilizadas doses de 0, 230 e 270 g ha-1 de isoxaflutole em amostras de Latossolo Vermelho Distroférrico nitossólico (textura argilosa) e doses de 0, 180 e 200 g ha-1 em amostras de Latossolo Vermelho distrófico (textura franco-argilo-arenosa). Em cada ensaio, foram combinados em esquema fatorial doses e períodos de seca após as aplicações do herbicida, utilizando-se B. decumbens como bioindicador da atividade residual do herbicida no solo. As avaliações de controle foram feitas aos 15, 30, 45 e 60 dias após a semeadura do bioindicador. O IFT apresentou alta estabilidade no solo de textura argilosa mesmo após três chuvas simuladas de 20 mm, espaçadas de 30 dias e seguidas de 120 dias de seca após sua aplicação. No solo de textura franco-arenosa a estabilidade foi menor, e o efeito residual (80% de controle) persistiu entre 0 e 110 dias para B. decumbens, conforme dose, períodos de seca e data de avaliação após a semeadura. Esse fato evidenciou que, à medida que aumenta o tempo e o número de irrigações entre a aplicação do herbicida e a semeadura do bioindicador, há redução no potencial efetivo de controle de IFT no Latossolo Vermelho distrófico.

Flufenacet and Isoxaflutole Combinations for Weed Control and Corn (Zea mays) Tolerance1

Field studies were conducted in 1999 and 2000 at seven locations in south Texas to evaluate flufenacet plus isoxaflutole for weed control and corn tolerance. Palmer amaranth control with flufenacent plus isoxaflutole was variable, with no greater than 60% control at one location and greater than 95% control at another. The poor control at the one location was probably due to lack of rainfall for 3 to 4 wk after corn was planted. Flufenacet plus isoxaflutole at 0.56 or 0.7 kg/ha controlled Texas panicum at least 80%, whereas flufenacet plus isoxaflutole rates lower than 0.56 kg/ha provided variable control (55 to 99%). Flufenacet plus isoxaflutole at 0.35 and 0.49 kg/ha controlled pitted morningglory at least 83%. Corn stunting (3 to 16%) with flufenacet plus isoxaflutole was noted at the one location where the soil sand content was greater than 80% and moisture was received within 48 h of herbicide application. With few exceptions, corn weed control and yield with flufenacet plus isoxaflutole combinations were generally comparable to those observed for the atrazine and acetochlor standard treatments.Nomenclature: Flufenacet; isoxaflutole; Palmer amaranth, Amaranthus palmeri S. Wats. #3 AMAPA; pitted morningglory, Ipomoea lacunosa (L.) # IPOLA; Texas panicum, Panicum texanum Buckl. # PANTE; corn, Zea mays L., ‘AS986’, ‘DK668’, ‘Pioneer 3223’, ‘Pioneer 32K61’.Additional index words: Corn tolerance, weed management.

Sensitivity of Selected Crops to Isoxaflutole in Soil and Irrigation Water

Isoxaflutole, a preemergence herbicide for use in corn, causes bleaching of plant tissue and plant death at low rates. A concern regarding widespread use of isoxaflutole is the unintentional exposure of high-value, minor hectareage crops that may be sensitive. Unintentional exposure could occur because of carryover from a previous application, spray drift, or contamination of irrigation water. The objective of this study was to determine the potential for injury to nine minor hectareage Michigan crops. Crops evaluated were: adzuki bean, alfalfa, carrot, cucumber, dry bean (navy and black beans), onion, sugar beet, and tomato. Experiments were conducted in the greenhouse to evaluate injury from low rates of isoxaflutole applied to soil to simulate carryover as well as low concentrations of isoxaflutole in 2.54 cm of irrigation water applied over the course of 1 h to 15-cm-tall plants. Isoxaflutole rates and concentrations that cause 20% injury (I20) were calculated using Seefeldt's log-logistic dose–response model. Regardless of application type, onion was always the least sensitive plant to isoxaflutole (I20= 37 g/ha applied to soil and 194 μg/L in irrigation water), whereas navy bean and black bean were the most sensitive (I20= 9 g/ha applied to soil and 5 μg/ L in irrigation water). The remaining plants exhibited intermediate sensitivity. All of the rates that resulted in injury were substantially less than the rates used for weed control in corn. Carryover from isoxaflutole applications in corn production may require plant back restrictions for certain sensitive crops.

Eficácia de isoxaflutole no controle de plantas daninhas na cultura da batata

This experiment was carried out at Bayer CropScience Experimental Station, in Paulinia, SP, Brazil, in a loamy soil cultivated with potato cv. Monalisa, during the 2002 growing season. The objectives were to evaluate the efficacy of isoxaflutole in weed control, to verify its selectivity to the potato crop and its effect on tubercule yield. The experimental design was a completely randomized block with seven treatments and four replications. The experimental plots consisted offour 7 m rows, with plants spaced in 0.60 m. The treatments were: controls (weedy and weedfree) and isoxaflutole rates (0.075, 0.150 and 0.300 kg/ha). Metribuzin (0.720 kg/ha) and linuron + metribuzin (0.910 + 0.384 kglha) were used as standards. The evaluations of the percentage ofweed control and the selectivity on the potato crop were carried out at 14, 28 and 42 days after treatment adopting a scale in which zero meant no weed control or no crop damage and one hundred corresponded to total control or death of the crop. The main weed species presented in the area were: Digitaria horizontalis Willd., Brachiaria plantaginea (Link.) Hitch, Gali nsoga parviflora Cav., Raphanus raphanistrum L. and Amaranthu s viridis L.. Potato plants did not show any visual symptoms of damage attributed to herbicide treatment. The species weed were efficiently controlled with isoxaflutole but there was no significant difference wheri compared with metribuzin. The treatments with isoxaflutole provided better control than linuron + metribuzin on grasses. Isoxaflutole did not affect the tubercule yield.