ALS-Inhibiting Herbicide Seed Treatments Control Striga hermonthica in ALS-Modified Corn (Zea mays)

Seed treatments with two acetolactate synthase (ALS)-inhibiting herbicides, the sulfonylurea herbicide nicosulfuron and the imidazolinone herbicide imazaquin, controlled the parasitic weed Striga hermonthica in corn. The XA-17 gene in ALS-modified P3180IR corn strongly reduced corn injury from herbicide seed treatments while another ALS modification was not effective. Combining seed treatment of ALS-inhibiting herbicides and ALS-modified corn with the XA-17 gene may offer a practical means for African growers to control Striga hermonthica.

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Witchweed [Striga hermonthica (Del.) Benth] control using imazapyr seed coating in maize hybrids in the Nigerian savannah

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0139 ◽

2020 ◽

Vol 100 (4) ◽

pp. 392-400

Author(s):

David Chikoye ◽

Ayeoffe Fontem Lum ◽

Abebe Menkir

Keyword(s):

Seed Treatment ◽

Acetolactate Synthase ◽

Field Trials ◽

Striga Hermonthica ◽

Cereal Crops ◽

Seed Coating ◽

Parasitic Weed ◽

Maize Hybrids ◽

Maize Seeds ◽

Genetic Tolerance

Witchweed [Striga hermonthica (Del.) Benth] is a major parasitic weed of most cereal crops in Africa, including maize. Seed treatment with low doses of acetolactate synthase–inhibiting herbicides, such as imazapyr, was introduced in the 1990s to control witchweed. Field trials were conducted in four locations in Nigeria in 2007 and 2008, to assess the effect of coating seeds of several maize hybrids with imazapyr on witchweed control. The hybrids had genes for imidazolinone herbicide resistance (IR), as well as genetic tolerance to witchweed (ST). Treatments were 12 IR maize hybrids with ST and three checks without the IR gene (commercial, witchweed tolerant, and witchweed susceptible hybrids). Averaged across all locations, the coated IR hybrids with ST yielded more and supported fewer witchweed plants than the uncoated IR hybrids with ST. The IR hybrids with ST yielded 57%–60% more than the commercial and witchweed tolerant hybrid checks that were not coated. The witchweed susceptible hybrid check suffered a yield loss of 88% under infestation without seed coating. The IR hybrids with ST yielded 3564 kg ha−1 of grain when coated with imazapyr and 3266 kg ha−1 otherwise. The findings indicate that coating of IR/ST maize seeds with imazapyr improved tolerance to witchweed.

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Evaluation of maize seed treatments for Pratylenchus zeae control

Nematology ◽

10.1163/15685411-00002898 ◽

2015 ◽

Vol 17 (6) ◽

pp. 667-670

Author(s):

Pedro Marcus de Souza Confort ◽

Mário M. Inomoto

Keyword(s):

Zea Mays ◽

Seed Treatment ◽

Root Mass ◽

Maize Seed ◽

Seed Treatments ◽

Maize Hybrid ◽

Maize Seeds ◽

The One ◽

Fourth Experiment ◽

Pratylenchus Zeae

The objective of this study was to evaluate the effects of maize (Zea mays) seed treatments for the control of Pratylenchus zeae under glasshouse conditions. Seeds of the maize hybrid DKB390 treated with thiametoxam, thiametoxam + abamectin and imidacloprid + thiodicarb were used as treatments. The treated maize seeds were sown in plastic cups containing soil inoculated with 200 nematodes (juveniles and females). Two of the four experiments that were done were evaluated at 60 and 90 days after sowing (DAS). The first experiment was evaluated 30, 60 and 90 DAS, and the fourth experiment only at 90 DAS. Fresh root mass and total nematodes extracted and counted from roots of each plant were used as the assessment criteria. All seed treatments tested showed a degree of efficacy in reducing the reproduction rates of P. zeae under glasshouse conditions. The imidacloprid + thiodicarb treatment showed consistent results in all replications of all four experiments, often being the one resulting in the lowest P. zeae density. The thiametoxam + abamectin treatment was also effective in reducing nematode numbers and differed significantly from the control treatments for all four experiments. Thiametoxam used on its own as a seed treatment proved to be as effective as the mixture with abamectin in two of the four experiments and does not provide consistent results in terms of reducing P. zeae population levels.

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Herbicide Seed Treatments for Control of Purple Witchweed (Striga hermonthica) in Sorghum and Millet

Weed Technology ◽

10.1614/wt-04-183r2.1 ◽

2005 ◽

Vol 19 (3) ◽

pp. 629-635 ◽

Cited By ~ 5

Author(s):

Bouréma Dembélé ◽

Daouda Dembélé ◽

James H. Westwood

Keyword(s):

Pearl Millet ◽

Acetolactate Synthase ◽

Seed Priming ◽

Striga Hermonthica ◽

Seed Treatments ◽

Parasitic Weeds ◽

Synthase Inhibitor ◽

Potential Use

A promising approach for the control of parasitic weeds is herbicide seed priming, which consists of soaking crop seeds in a herbicide solution such that the herbicide is later present in the crop seedling to inhibit growth of attaching parasites. This technique is effective where selectivity exists between crop and parasite; for example, varieties of imidazolinone-resistant maize. However, seed priming has not been reported for sorghum or pearl millet, two crops that are greatly affected by purple witchweed. Research was initiated to evaluate herbicides for potential use as seed priming agents in these crops. Auxin-mimic and acetolactate synthase-inhibitor class herbicides were evaluated; specifically, clopyralid, 2,4-DB, dicamba, picloram, and prosulfuron. For sorghum, immersion of seed in 0.5% (w/v) ae 2,4-DB for 5 min 1 d before planting reduced purple witchweed densities to levels 20 to 50% of nontreated controls. However, this concentration was at the threshold of crop toxicity and reduced sorghum yields in some experiments. None of the herbicides tested consistently reduced purple witchweed on pearl millet. This research illustrates both the potential and limitations of adapting seed priming technology for sorghum and pearl millet.

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Reduction of Imazaquin Injury to Corn (Zea mays) and Sorghum (Sorghum bicolor) by Antidotes

Weed Science ◽

10.1017/s0043174500055818 ◽

1989 ◽

Vol 37 (1) ◽

pp. 34-41 ◽

Cited By ~ 9

Author(s):

Michael Barrett

Keyword(s):

Zea Mays ◽

Sorghum Bicolor ◽

Seed Treatment ◽

Acetolactate Synthase ◽

Soil Treatment ◽

Naphthalic Anhydride ◽

Toxic Metabolites ◽

Injury Treatment ◽

Plant Injury ◽

Injury Protection

Antidotes were evaluated for their ability to prevent corn and sorghum injury caused by imazaquin. Plant injury was reduced in both preemergence and early postemergence imazaquin applications. Naphthalic anhydride (NA) seed treatment was the most consistent compound in reducing the imazaquin injury. Seed treatment with CGA 92194 or flurazole also gave injury protection to corn and sorghum, while soil treatment with dichlormid provided the least protection from imazaquin injury. Treatment with the antidotes did not affect the acetolactate synthase (ALS) (EC4.1.3.18) activity in corn or sorghum tissues. Imazaquin treatments decreased extractable ALS activity but this decrease was eliminated, partially or totally, by the most effective antidotes. Antidote treatments had little effect on absorption and distribution of14C in plants growing in soil treated with14C-imazaquin. Antidote treatments increased the metabolism of14C-imazaquin to both soluble and unextractable14C after 24 h of exposure. The increased rate of imazaquin conversion to less toxic metabolites when antidotes were used resulted in a reduction in imazaquin injury to corn and sorghum.

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Potential of cinosulfuron and CGA152005 seed treatment for control of Striga hermonthica in upland rice

Acta Agronomica Hungarica ◽

10.1556/aagr.50.2002.1.2 ◽

2002 ◽

Vol 50 (1) ◽

pp. 7-18 ◽

Cited By ~ 5

Author(s):

M. A. Adagba ◽

T. O. Lagoke ◽

B. N. Singh ◽

Keyword(s):

Seed Treatment ◽

Upland Rice ◽

Rice Variety ◽

Striga Hermonthica ◽

Resistant Variety ◽

Rice Grain ◽

Seed Treatments ◽

Rice Varieties ◽

Grain Yields ◽

Four Levels

Field trials were conducted in the dry and wet seasons of 1998 at Samaru (11°11' N, 07° 38' E, 686 m above sea level) in the northern Guinea savanna of Nigeria, to investigate the potential of cinosulfuron and CGA152005 seed treatments on the reaction of upland rice varieties to Striga hermonthica (Del.) Benth. Seven varieties of upland rice formed the main plots treatments while four levels each of cinosulfuron at 0.1, 0.2, 0.4 and 0.6 g/l and CGA152005 at 0.008, 0.016, 0.032 and 0.064 g/l, as well as two no herbicide treatments of dry sowing and distilled water-soaked planting were assigned to the subplots. The experiment was laid out in a split plot design and replicated three times. The resistant varieties FARO 40 and WAB 56-50 did not support Striga emergence and also produced grain yields which were the maximum, or comparable to the maximum. FARO 11, a susceptible variety, produced high grain yields in spite of support for early, high Striga emergence. In spite of delayed emergence of Striga on FARO 38 and FARO 48, these varieties, as well as FARO 46 and FARO 45, supported high Striga emergence, exhibited high crop reaction scores to Striga and produced low grain yields. The seed treatment of upland rice varieties with cinosulfuron at 0.2 to 0.6 g/l and CGA152005 at 0.032 and 0.064 g/l significantly delayed Striga emergence compared with the lower rates. After seed treatment with cinosulfuron at 0.6 g/l, the susceptible rice variety FARO 38 and the resistant variety WAB 56-50 produced rice grain yields comparable to the maximum obtained with FARO 40 given seed treatment with CGA 152005 at 0.064 g/l. The significant interactions of varieties of upland rice and herbicide seed treatments on the number of days to first Striga emergence, Striga shoot count and crop reaction to Striga confirm the differential influence of various concentrations of the herbicide seed treatments on the virulence of Striga hermonthica on varieties of upland rice.

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Influence of a thiamethoxam seed treatment on acetolactate synthase–inhibiting herbicide–induced injury to inbred and hybrid imidazolinone-resistant rice

Weed Technology ◽

10.1017/wet.2019.1 ◽

2019 ◽

Vol 33 (2) ◽

pp. 253-257

Author(s):

Steven M. Martin ◽

Jason K. Norsworthy ◽

Robert C. Scott ◽

Jarrod Hardke ◽

Gus M. Lorenz ◽

...

Keyword(s):

Field Experiment ◽

Seed Treatment ◽

Acetolactate Synthase ◽

Growing Season ◽

Canopy Height ◽

Herbicide Application ◽

Seed Treatments ◽

Final Treatment ◽

Herbicide Treatments ◽

Potential Benefits

AbstractThe increased use of insecticide seed treatments in rice has raised many questions about the potential benefits of these products. In 2014 and 2015, a field experiment was conducted near Stuttgart and Lonoke, AR, to evaluate whether an insecticide seed treatment could possibly lessen injury from acetolactate synthase (ALS)–inhibiting herbicides in imidazolinone-resistant (IR) rice. Two IR cultivars were tested (a hybrid, ‘CLXL745’, and an inbred, ‘CL152’), with and without an insecticide seed treatment (thiamethoxam). Four different herbicide combinations were evaluated: a nontreated control, two applications of bispyribac-sodium (hereafter bispyribac), two applications of imazethapyr, and two applications of imazethapyr plus bispyribac. The first herbicide application was to two- to three-leaf rice, and the second immediately prior to flooding (one- to two-tiller). At both 2 and 4 wk after final treatment (WAFT), the sequential applications of imazethapyr or bispyribac plus imazethapyr were more injurious to CLXL745 than CL152. This increased injury led to decreased groundcover 3 WAFT. Rice treated with thiamethoxam was less injured than nontreated rice and had improved groundcover and greater canopy heights. Even with up to 32% injury, the rice plants recovered by the end of the growing season, and yields within a cultivar were similar with and without a thiamethoxam seed treatment across all herbicide treatments. Based on these results, thiamethoxam can partially protect rice from injury caused by ALS-inhibiting herbicides as well as increase groundcover and canopy height; that is, the injury to rice never negatively affected yield.

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Effect of Biostimulants in Late Seeding of Genotypes of Zea mays L.

Journal of Experimental Agriculture International ◽

10.9734/jeai/2019/v41i630431 ◽

2019 ◽

pp. 1-9

Author(s):

Luiz Leonardo Ferreira ◽

Hiago Zanon Barbosa ◽

Ivan Ricardo Carvalho ◽

Roselaine Lages Fonseca Prado ◽

Carmen Rosa da Silva Curvêlo ◽

...

Keyword(s):

Zea Mays ◽

Water Stress ◽

Yield Components ◽

Seed Treatment ◽

Zea Mays L ◽

Seed Treatments ◽

Genotype Effect ◽

Stress Environment ◽

Residual Variances ◽

Ear Number

Seed treatment has as its main feature the prevention of pest entry in cultivated areas, besides being of great importance in the development of vigorous and healthy plants. The objective of this work was to evaluate the performance of corn genotypes with biostimulant in seed treatment under water stress environment. The experimental design was randomized blocks in a 3x3 factorial scheme, corresponding to three corn genotypes (P3707, P30S31 and P30F35) and three seed treatments with the biostimulants (ConrSeeds, Stimulate and Água). The experiment was carried out at Luiz Eduardo de Oliveira Sales Experimental Farm, located in the municipality of Mineiros, Goiás, from March 2018 to August 2018. Plant height, stem diameter, ear insertion height, number of rows per ear, number of grains per row, number of grains per ear and yield were evaluated. The obtained data was submitted to the assumptions of the statistical model, verifying the normality and homogeneity of the residual variances, as well as the additivity of the model, testing univariate and multivariate analyzes. Analysis of variance revealed significance only for the main genotype effect. Seed treatments did not improve yield components of corn genotypes. The genotypes differed, where the variables number of rows per ear, number of grains per row and number of grains per ear directly influenced the grain yield.

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Chlorbromuron-Carbofuran Interaction in Corn and Barley

Weed Science ◽

10.1017/s0043174500027132 ◽

1973 ◽

Vol 21 (4) ◽

pp. 335-338 ◽

Cited By ~ 12

Author(s):

Allan S. Hamill ◽

Donald Penner

Keyword(s):

Zea Mays ◽

Hordeum Vulgare ◽

Leaf Area ◽

Seed Treatment ◽

Net Photosynthesis ◽

Dry Weight ◽

Interaction Effects ◽

Sand Culture ◽

Seed Treatments ◽

Corn Roots

Treatments with the herbicide 3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea (chlorbromuron) were combined with seed treatments with the insecticide, 2,2-dimethyl-2, 3-dihydrobenzofuranyl-7-N-methylcarbamate (carbofuran), to measure phytotoxic interaction effects on barley (Hordeum vulgareL. ‘Larker’) and corn (Zea maysL. ‘Michigan 400’). The combination synergistically reduced radicle length in barley seedlings and reduced the leaf area and dry weight of 7-day-old corn seedlings grown in sand culture. The chlorbromuron-carbofuran combination reduced net photosynthesis in barley and corn and increased respiration in barley. The14C from14C-chlorbromuron preferentially accumulated in barley and corn shoots. The carbofuran seed treatment resulted in a reduced level in barley shoots and corn roots but increased the accumulation of14C in barley roots and corn shoots. The basis for this interaction appeared related to the increased accumulation of chlorbromuron in corn and barley shoots and reduced chlorbromuron metabolism.

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