Field Evaluations of Herbicides on Vegetable, Small Fruit, and Ornamental Crops, 2000, 2001, & 2002

Field evaluations of herbicides provide the chemical industry, governmental agencies, such as IR-4, and the Arkansas Agricultural Experiment Station with an evaluation of herbicide performance on small fruit, vegetable, and ornamental crops grown under Arkansas conditions. This report provides a means for disseminating information to interested private and public service weed scientists

Green foxtail (Setaria viridis) resistance to acetolactate synthase inhibitors

Des sétaires vertes (Setaria viridis) présumées résistantes aux inhibiteurs de l'acétolactate synthase (ALS) ont été identifiées en 1999 au Wisconsin, É.-U., dans un champ de soja (Glycine max) issu d'un semis direct. La résistance aux herbicides imidazolinone et sulfonylurée a été caractérisée au niveau de la plante entière et de celui des enzymes. Ces sétaires vertes au stade trois à quatre feuilles étaient respectivement 1020, 53 et 6,5 fois plus résistantes à l'imazethapyr, à l'imazamox et au nicosulfuron que les sétaires sensibles. L'ALS in vivo était respectivement 1300 et 1,7 fois plus résistante à l'imazethapyr et au nicosulfuron. Ces résultats laissent supposer que ce groupe de sétaires vertes était très résistant à l'imazethapyr et à l'imazamox, et que la résistance est associée à un enzyme ALS insensible.Green foxtail (Setaria viridis) plants putatively resistant to acetolactate synthase (ALS) inhibitors were identified in a Wisconsin USA no-tillage soybean (Glycine max) field in 1999. Resistance to imidazolinone and sulfonylurea herbicides was characterized at the whole-plant level and enzyme level. Three- to four-leaf stage green foxtail plants were 1020, 53, and 6.5-fold resistant to imazethapyr, imazamox, and nicosulfuron, respectively, compared to susceptible plants. In vivo ALS was 1300 and 1.7-fold resistant to imazethapyr and nicosulfuron, respectively. These results suggested that this green foxtail accession was highly resistant to imazethapyr and imazamox, and that resistance was associated with an insensitive ALS enzyme

Field Evaluation of Herbicides on Vegetables and Small Fruits 2004

Herbicide evaluation studies on vegetables and small fruits were conducted in 2004 at the Arkansas Agricultural Experiment Station at Fayetteville, AR, in an effort to evaluate new herbicides, herbicide mixtures, and their application timings for weed control efficacy and crop tolerance. Results of these studies, in part, provide useful information to producers, fellow researchers, the Crop Protection Industry, and the IR-4 Minor Crop Pest Management Program in the development of potential new herbicide uses in vegetable, and fruit

Response of weed management practices on the Productivity of urdbean (Vigna mungo L. Hepper)

A field Investigation was carried out to evaluate the effect of hand weedings and herbicides on the weed flora, growth and yield of urdbean (Vigna mungo). The experiment was conducted during kharif season 2011 in loamy sand soil, to study the effect of different Ten weed management treatments comprising weedy check, weed free, one hand weeding (HW) at 20 days after sowing (DAS), two HW at 20 and 40 DAS, trifluralin at 0.75 kg/ha, alachlor at 1.5 kg/ha, imazethapyr at 0.10 kg/ha, trifluralin at 0.75 kg/ha + HW at 30 DAS, alachlor at 1.5 kg/ha + HWat 30 DAS and imazethapyr at 0.10 kg/ha + HW at 30 DAS on urdbean. Results showed that the maximum plant height was recorded under weed free treatment at all the growth stages and the maximum dry matter accumulation of 108.88 and 159.31 g per metre row length at 50 DAS and harvest stages was obtained under imazethapyr at 0.10 kg/ha + HW at 30 DAS treatment that was significantly higher by 17.8, 21.8, 24.6, 31.8 and 56.0 per cent at 50 DAS and 20.4, 17.6, 25.4, 29.0 and 50.1 per cent at harvest stage over imazethapyr at 0.10 kg/ha, one HW at 20 DAS, alachlor at 1.5 kg/ha, trifluralin at 0.75 kg/ha and weedy check treatments, respectively.. Application pre emergence application of imazethapyr at 0.10 kg/ha + HW at 30 DAS was found the most effective treatment with regard of grain yield (1403 kg/ha) and net returns (Rs 34815/ha). Two hand weedings done at 20 and 40 DAS also produced grain yield of 1392 kg/ha with net returns of Rs 33469 /ha

Effect of rate of application on degradation of imazethapyr in groundnut and soil under tropical Indian condition

Pesticides though formulated to be biologically degradable, few herbicides reported to cause surface and groundwater contamination which needs the monitoring of herbicide residues in environment continuously. Thus, to monitor the persistence and residues in crops, imazethapyr degradation studies were conducted in soil with groundnut cropping under Indian tropical condition. A groundnut field was treated with different doses of imazethapyr as early post emergence. Results showed that the degradation of imazethapyr in soil and groundnut plant followed first order reaction kinetics irrespective of the dose. The residue of imazethapyr persists in soil up to 60 days at higher rates of application while it persists up to 30 days in plant with the calculated half life of 2.8 to 7.4 days in soil and 5.1 to 5.9 days in plant. At the time of harvest, the residue of imazethapyr in soil, groundnut haulm or pods were below the detectable limit of 0.008 mg/kg across different doses of application. However, the continuous and inappropriate use in light textured soils may cause groundwater contamination and bioaccumulation in plant system. Hence, a pre harvest interval of 75 days must be allowed after the application of imazethapyr for the weed control in groundnut

The potential use of oil palm frond mulch treated with imazethapyr for weed control in Malaysian coconut plantation

Introduction of new weed management strategy for coconut plantation in Malaysia is essential since the current weed control methods are less effective and highly herbicide dependent, thus leading to development of herbicide resistance in weeds as well as environmental and human health concerns. Thus, the present study aimed to evaluate the phytotoxic effects of oil palm frond mulch treated with imazethapyr at a reduced rate on weed emergence and growth. The results of glasshouse experiments have shown that imazethapyr at 12 g a.i. ha-1 in combination with oil palm residues of leaflet (OPL), rachis (OPR) or frond (OPF) at rates of 1.4-1.8 t ha-1 inhibited Eleusine indica emergence and growth by 90-100%, implying that imazethapyr is compatible with oil palm residue mulches. In the field experiment, hand weeding followed by OPF at 3.4 t ha-1 treated with imazethapyr at 24 g a.i. ha-1 have demonstrated excellent control of Mikania micrantha, Asystasia gangetica, Phyllanthus amarus, Panicum sp. and Echinochloa colona by reducing their total dry weight up to 95% at three months after treatment. The present results suggested that the integration of chemical, physical and mechanical methods can provide effective weed control in the coconut plantation for months

Bio-efficacy of tank mixed herbicides for control of complex weed flora in soybean (Glycine max L. Merril)

A field experiment was conducted at ZARS, Jhabua (M.P.) during kharif 2014 to find out most suitable and efficient method of weed control in soybean. The experiment consisted of nine treatments laid out in randomized block design with three replications. All the weed management practices led to significant reduction in density and dry matter of weeds as compared to weedy check. Two hand weeding (20 & 40 DAS) recorded lowest weed density (4.9/ m2), weed dry matter (22.35 g/m2) with highest weed control efficiency of 59.67% and found at par with the application of Chlorimuron Ethyl @ 9gm /ha + Quizalofop-p-ethyl @ 50 g /ha (density 5.48/ m2, dry matter 26.62 g/m2 and WCE of 51.97%) and Imazethapyr @ 35 g /ha + Imazamox @ 35 g/ha (density 6.13/ m2, dry matter 26.00 g/m2 and WCE of 53.08%). Maximum yield of 1782 kg/ha was recorded in two hand weeding (20 & 40 DAS) closely followed by Chlorimuron Ethyl @ 9gm /ha + Quizalofop-p-ethyl @ 50 g /ha (1723 kg/ha) and Imazethapyr @ 35 g / ha + Imazamox @ 35 g/ha (1697 kg/ha). Reduction in soybean yield in weedy check to be recorded is 38.78 per cent when compared to weed free and 36.68 per cent in comparison to Chlorimuron Ethyl @ 9gm /ha + Quizalofopp-ethyl @ 50 g /ha. However, highest Benefit to Cost ratio is recorded in Chlorimuron Ethyl +Quizalofop-p-ethyl (3.26) closely followed by Imazethapyr + Imazamox (3.22) and Weed free (3.21)

Girassol Clearfield consorciado com Brachiaria ruziziensis utilizando herbicidas inibidores da enzima aceto-lactato sintase (ALS).

O objetivo desse experimento foi avaliar a tolerância do girassol (Helianthus annuus) e a supressão do capim-braquiária (Brachiaria ruziziensis) a herbicidas inibidores da enzima aceto-lactato sintase (ALS). O delineamento experimental foi blocos casualizados, com quatro repetições. Os tratamentos foram i) imazethapyr 30 g i.a./ha; ii) imazethapyr 70 g i.a./ha; iii) imazapyr 75 g e.a./ha; iv) imazapyr 125 g e.a./ha; v) chlorimuron-ethyl 7,5 g i.a./ha; vi) chlorimuron-ethyl 12,5 g i.a./ha; vii) nicosulfuron 8 g i.a./ha; viii) nicosulfuron 20 g i.a./ha; ix) testemunha sem capina e x) testemunha capinada. Os tratamentos com imazethapyr (30 e 70 g i.a./ha), imazapyr (75 e 125 g e.a./ha) e nicosulfuron (8 e 20 g i.a./ha) não causaram injúrias às plantas de girassol. O chlorimuron-ethyl nas doses de 7,5 e 12,5 g i.a./ha resultou em alto grau de fitointoxicação às plantas de girassol. O imazethapyr (30 e 70 g i.a./ha) e o nicosulfuron (8 g i.a./ha) causaram supressão do crescimento das plantas de B. ruziziensis. Entretanto, o imazapyr (75 e 125 g e.a./ha) e a maior dose de nicosulfuron (20 g i.a./ha) afetaram drasticamente a produção de fitomassa da forrageira, com morte das plantas