Seedbed preparation, timing of seeding, fertility and root pathogens affect establishment and yield of alfalfa

2002 ◽  
Vol 82 (2) ◽  
pp. 371-381 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
K. F. Chang ◽  
R. J. Howard
Keyword(s):  
Seed Treatment ◽  
Fungal Pathogens ◽  
Plant Density ◽  
Seedling Emergence ◽  
Stand Density ◽  
Pathogenic Fungi ◽  
Field Trials ◽  
Forage Yield ◽  
Seedbed Preparation ◽  
The Impact

Invasion by grasses and weedy species occurs when plant density in alfalfa fields falls below critical levels. Several soil-borne fungal pathogens can reduce stand density in alfalfa by impeding seedling establishment and by killing older plants weakened by other stresses. Surveys of alfalfa fields were conducted in 1997, and pathogenic fungi from rotted roots were isolated and identified. Isolates of selected pathogens were applied with the seed in field trials to assess the impact of fertilizer and seeding system (conventional vs. sod-seeding, spring vs. dormant-fall seeding) on seedling emergence and subsequent productivity when disease pressure was high. The impact of various fungicide seed treatments was also assessed. Seed treatment improved seedling emergence and initial forage productivity in one of three trials; however, it had little effect on long-term forage yield. Addition of sulphur fertilizer had little effect on seedling emergence or survival, but improved forage productivity at all three trial sites. Sod-seeded plots suffered more winterkill and were less vigorous than plots seeded into a tilled seedbed. Seedling emergence was lower when seedlings were planted in the fall than in the spring. However, fall-seeded treatments showed a less adverse response to inoculum treatments and, in some cases, these seedlings were able to take advantage of early-season moisture to produce higher yields than their spring-seeded counterparts. Key words: Medicago, Fusarium, Pythium, Phoma, fungicide, seed treatment, fertilizer, tillage

The effect of seed size, seed treatment, seeding date and depth on Rhizoctonia seedling blight of canola

2014 ◽  
Vol 94 (2) ◽  
pp. 311-321 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
G. D. Turnbull ◽  
B. D. Gossen ◽  
S. E. Strelkov
Keyword(s):  
Seed Size ◽  
Seed Yield ◽  
Seed Treatment ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Field Trials ◽  
Seedling Blight ◽  
Substantial Impact ◽  
Seeding Date ◽  
The Impact

Hwang, S. F., Ahmed, H. U., Turnbull, G. D., Gossen, B. D. and Strelkov, S. E. 2014. The effect of seed size, seed treatment, seeding date and depth on Rhizoctonia seedling blight of canola. Can. J. Plant Sci. 94: 311–321. Rhizoctonia solani can have a substantial impact on seedling establishment and productivity of canola (Brassica napus). The effects of seeding date, seeding depth, seed size, and seed treatment on seedling blight of canola were evaluated under greenhouse and field conditions. Early seeding resulted in higher seedling emergence in one trial year and higher seed yield in all trial years relative to a late-seeded treatment. Mid-sized seed (range 0.7–2.0 mm diam.) had greater seedling emergence in R. solani-inoculated growth medium in a greenhouse trial and higher seed yield in one of two field trials compared with smaller seed (<0.7 mm). In the greenhouse study, sowing of large seed resulted in greater plant height and shoot weight compared with sowing of smaller seed. The effect of seeding depth was significant only on shoot dry weight, which increased at a seeding depth of 2.6 cm. Seed treatment with Helix Xtra (thiamethoxam+difenconazole+metalaxyl+fludioxonil), and Prosper FX (clothianidin+carboxin+trifloxystrobin+metalaxyl) resulted in a significant increase in seedling emergence and yield compared with the inoculated control. These results indicate that fungicidal seed treatment can minimize the impact of R. solani on canola.

scholarly journals The Mechanisms of Mating in Pathogenic Fungi—A Plastic Trait

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 831
Author(s):  
Jane Usher
Keyword(s):  
Fungal Pathogens ◽  
Crop Yields ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Yeast Saccharomyces Cerevisiae ◽  
Closely Related Species ◽  
Sexual And Asexual Reproduction ◽  
Target Dna ◽  
High Degree ◽  
The Impact

The impact of fungi on human and plant health is an ever-increasing issue. Recent studies have estimated that human fungal infections result in an excess of one million deaths per year and plant fungal infections resulting in the loss of crop yields worth approximately 200 million per annum. Sexual reproduction in these economically important fungi has evolved in response to the environmental stresses encountered by the pathogens as a method to target DNA damage. Meiosis is integral to this process, through increasing diversity through recombination. Mating and meiosis have been extensively studied in the model yeast Saccharomyces cerevisiae, highlighting that these mechanisms have diverged even between apparently closely related species. To further examine this, this review will inspect these mechanisms in emerging important fungal pathogens, such as Candida, Aspergillus, and Cryptococcus. It shows that both sexual and asexual reproduction in these fungi demonstrate a high degree of plasticity.

Effect of seed damage and metalaxyl seed treatment on pythium seedling blight and seed yield of field pea

2001 ◽  
Vol 81 (3) ◽  
pp. 509-517 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
K. F. Chang ◽  
G. D. Turnbull ◽  
R. J. Howard
Keyword(s):  
Seed Yield ◽  
Seed Treatment ◽  
Effective Means ◽  
Seedling Emergence ◽  
Field Pea ◽  
Laboratory Studies ◽  
Seed Vigour ◽  
Stand Establishment ◽  
Seed Damage ◽  
The Impact

When cool, wet conditions persist after planting, Pythium spp. can be an important constraint to stand establishment in field pea. Laboratory studies and field trials were conducted over 3 yr to assess the impact and evaluate the interactions of Pythium spp., metalaxyl seed treatment and damage to seed on seedling establishment, root rot severity and seed yield of field pea. Seedling emergence, seedling size, and seed yield were reduced by inoculation with Pythium spp. and by mechanical damage to the seed. Fungicide seed treatment reduced the impact of seed damage, but did not always restore seedling emergence and seed yield to the same level as from undamaged seed. Undamaged seed treated with metalaxyl was not affected by inoculation with Pythium spp. Differences among cultivars, although often significant, were small relative to the effect of seed injury. Laboratory studies showed a negative linear relationship between inoculum concentration and emergence from untreated seed. They also showed that Pythium spp. had a similar impact on seedling emergence in cool (20/10°C day/night) and cold (12/6°C) soils. This study showed that planting fungicide-treated, high-quality field seed was an effective means of maximizing emergence and stand establishment for commercial field pea production. Key words: Pisum sativum, seed vigour, metalaxyl, Pythium, seed damage

scholarly journals Regression Analyses for Evaluating the Influence of Bacillus cereus on Alfalfa Yield Under Variable Disease Intensity

2000 ◽  
Vol 90 (6) ◽  
pp. 657-665 ◽  
Author(s):  
Elizabeth R. Kazmar ◽  
Robert M. Goodman ◽  
Craig R. Grau ◽  
David W. Johnson ◽  
Erik V. Nordheim ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Untreated Control ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Field Trials ◽  
Forage Yield ◽  
Regression Methods ◽  
Control Response ◽  
Treated Seed ◽  
Yield Gain

We developed and tested regression methods to exploit the variability in disease inherent in field experiments, and applied the methods to evaluate strains of Bacillus cereus for biocontrol efficacy. Four B. cereus strains were tested for their effect on alfalfa (Medicago sativa) performance in 16 field trials planted during 1993 to 1996 at multiple sites in Wisconsin. To evaluate performance of the strains, we used the ratio of (metalaxyl response)/(untreated control response) as a measure of disease intensity within the experiments. The ratio of (Bacillus response)/(untreated control response) was then regressed as a function of disease intensity. The slope of the resulting line provides a statistical test to compare performance of the Bacillus strain with that of the untreated seed (Ho: slope = 0) and metalaxyl controls (Ho: slope = 1). Under conditions in which disease occurred, forage yield of plots planted with seed treated with B. cereus strain AS4–12 exceeded yield from the untreated control plots (P = 0.002) and was similar to yield of plots planted with metalaxyl-treated seed (P = 0.14). Yield gain associated with AS4–12 and metalaxyl seed treatment averaged 6.1 ± 2.8% (±standard error) and 3.0 ± 2.8%, respectively. In contrast to the regression approach, means analysis by analysis of variance did not detect differences among treatments. Three other B. cereus strains either did not increase alfalfa yield or increased yield less than did AS4–12. Metalaxyl and three of the Bacillus strains increased seedling emergence, but the improved stands were not predictive of increased forage yield. In six additional studies conducted for one season in 1997, AS4–12 enhanced yield of two cultivars at diverse locations in Wisconsin, but there was an apparent cultivar-location interaction. A strong correlation between response to AS4–12 and metalaxyl treatment suggests that these treatments controlled similar pathogens, most likely the oomycete pathogens Phytophthora medicaginis and Pythium spp.

scholarly journals Beneficial Effects of Solid Matrix Chemo-priming in Okra

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 535-537 ◽  
Author(s):  
K. E. Conway ◽  
R. Mereddy ◽  
B. A. Kahn ◽  
Y. Wu ◽  
S. W. Hallgren ◽  
...  
Keyword(s):  
Untreated Control ◽  
Seed Treatment ◽  
Seedling Emergence ◽  
Pythium Ultimum ◽  
Field Trials ◽  
Solid Matrix ◽  
Damping Off ◽  
Untreated Seed ◽  
Beneficial Effects ◽  
Emergence And Reduction

Two field trials at Stillwater and Bixby, OK, evaluated the efficacy of solid matrix priming techniques, alone or in combination with fungicide seed treatment on seedling emergence and reduction of damping-off of okra in field soil naturally infested with Pythium ultimum. The following treatments were evaluated: thiram + carboxin (chemo-primed) (commercially applied), biological seed treatment (bio-primed) (Trichoderma harzianum isolate OK-110, 1 g suspended in 1% carboxymethylcellulose [CMC]), untreated seed (control), and a 1% CMC control. Chemo-primed seeds had a more uniform and faster emergence compared with untreated seeds at both field sites. Within 3 days, 92 and 78% of chemo-primed seeds had emerged at Stillwater and Bixby, respectively, compared with 84 and 71% emergence in the untreated control. Mean emergence of chemo-primed seeds was lower (P ≤ 0.05) than the untreated control. Chemo-primed seeds had greater vigor (P≤ 0.05) at both locations compared with either fungicide-treated or priming alone, at both locations. There were no differences (P ≤ 0.05) in yield among treatments at both locations. P. ultimum was consistently isolated from damped-off seedlings and surrounding soil at both locations. Isolates of P. ultimum were more pathogenic on okra in laboratory tests than isolates of Rhizoctonia spp., Fusarium spp., and other Pythium spp. also isolated from seed or soil.

scholarly journals Biological Control of Pathogens Causing Root Rot Complex in Field Pea Using Clonostachys rosea Strain ACM941

2003 ◽  
Vol 93 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Allen G. Xue
Keyword(s):  
Root Rot ◽  
Seed Treatment ◽  
Fungal Pathogens ◽  
Seedling Emergence ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Limiting Factor ◽  
Aphanomyces Euteiches ◽  
Clonostachys Rosea

Pea root rot complex (PRRC), caused by Alternaria alternata, Aphanomyces euteiches, Fusarium oxysporum f. sp. pisi, F. solani f. sp. pisi, Mycosphaerella pinodes, Pythium spp., Rhizoctonia solani, and Sclerotinia sclerotiorum, is a major yield-limiting factor for field pea production in Canada. A strain of Clonostachys rosea (syn. Gliocladium roseum), ACM941 (ATCC 74447), was identified as a mycoparasite against these pathogens. When grown near the pathogen, ACM941 often was stimulated to produce lateral branches that grew directly toward the pathogen mycelium, typically entwining around the pathogen mycelium. When applied to the seed, ACM941 propagated in the rhizosphere and colonized the seed coat, hypocotyl, and roots as the plant developed and grew. ACM941 significantly reduced the recovery of all fungal pathogens from infected seed, increased in vitro seed germination by 44% and seedling emergence by 22%, and reduced root rot severity by 76%. The effects were similar to those of thiram fungicide, which increased germination and emergence by 33 and 29%, respectively, and reduced root rot severity by 65%. When soil was inoculated with selected PRRC pathogens in a controlled environment, seed treatment with ACM941 significantly increased emergence by 26, 38, 28, 13, and 21% for F. oxysporum f. sp. pisi, F. solani f. sp. pisi, M. pinodes, R. solani, and S. sclerotiorum, respectively. Under field conditions from 1995 to 1997, ACM941 increased emergence by 17, 23, 22, 13, and 18% and yield by 15, 6, 28, 6, and 19% for the five respective pathogens. The seed treatment effects of ACM941 on these PRRC pathogens were greater or statistically equivalent to those achieved with thiram. Results of this study suggest that ACM941 is an effective bioagent in controlling PRRC and is an alternative to existing chemical products.

Effects of soil-borne Rhizoctonia solani on canola seedlings after application of glyphosate herbicide

2013 ◽  
Vol 93 (1) ◽  
pp. 97-107 ◽  
Author(s):  
A. Rashid ◽  
S. F. Hwang ◽  
H. U. Ahmed ◽  
G. D. Turnbull ◽  
S. E. Strelkov ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Weed Management ◽  
Management Practice ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Field Trials ◽  
Shoot Dry Weight ◽  
Subsequent Crop ◽  
Glyphosate Herbicide ◽  
The Impact

Rashid, A., Hwang, S. F., Ahmed, H. U., Turnbull, G. D., Strelkov, S. E. and Gossen, B. D. 2013. Effects of soil-borne Rhizoctonia solani on canola seedlings after application of glyphosate herbicide. Can. J. Plant Sci. 93: 97–107. Application of glyphosate (N-phosphonomethyl glycine) prior to seeding is a common weed management practice in many agricultural systems. However, there are concerns that this practice may increase the impact of soil-borne diseases on the crop, even in cultivars that are resistant to glyphosate. In the current study, the effects of pre-plant applications of glyphosate on seedling blight of canola caused by Rhizoctonia solani and subsequent crop growth were examined under field and greenhouse conditions. Under greenhouse conditions in soil inoculated with R. solani, glyphosate application 15 d before seeding reduced seedling emergence, increased damping-off, and decreased plant height and shoot dry weight of canola relative to a glyphosate-free control. However, the adverse effects were substantially reduced when the crop was seeded 33 d after glyphosate application. This indicates that glyphosate application prior to planting may increase the impact of R. solani on canola seedlings, but that this effect diminishes quite rapidly. Soil populations of R. solani declined over the 33-d period regardless of glyphosate treatment. Glyphosate application 10 d before seeding increased seedling emergence and seed yield (1 of 2 yr) of canola in field trials inoculated with R. solani.

Effects of inoculum density, temperature, seeding depth, seeding date and fungicidal seed treatment on the impact of Rhizoctonia solani on lentil

2008 ◽  
Vol 88 (4) ◽  
pp. 799-809 ◽  
Author(s):  
K. F. Chang ◽  
S. F. Hwang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
H. Wang ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Seedling Establishment ◽  
Root Rot ◽  
Seed Treatment ◽  
Field Experiments ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Inoculum Density ◽  
Seeding Date ◽  
The Impact

Rhizoctonia solani causes seedling blight and root rot in lentil, which reduces plant populations and the vigour and yield of surviving plants. Factors in the seedling environment, such as inoculum density, temperature, seeding depth, seeding date, and fungicidal seed treatment were studied to determine the degree to which they affect the impact of R. solani on lentil seedlings. Survival of lentil plants was evaluated after planting into soil artificially inoculated with various concentrations of a highly aggressive isolate of R. solani (AG-4). Emergence, seedling survival and shoot dry matter production decreased with increasing inoculum density, but these declines varied with temperature. Low soil temperatures delayed the emergence of lentil seedlings in non-inoculated soil, but in inoculated soils, emergence was inhibited with increasing temperatures. Depth of seeding did not affect seedling establishment, but root rot severity increased with depth of seeding in a growth cabinet trial. Root nodulation was reduced as root rot severity increased. In field experiments carried out over 3 station years, seeding date had a substantial effect on seedling emergence and yield of inoculated treatments, but the trends were not consistent between sites. In field assessments of fungicide efficacy, treatment of seed with thiabendazole plus carbathiin (Crown) and carbathiin plus thiram (Vitaflo 280) improved seedling establishment relative to the inoculated control. Key words: Lens culinaris, damping-off, root rot, seeding date, fungicide seed treatment depth of seeding, thiabendazole, carbathiin, thiram

scholarly journals Role of the Fungicide Seed Dressing in Controlling Seed-Borne Fusarium spp. Infection and in Enhancing the Early Development and Grain Yield of Maize

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 784
Author(s):  
Luca Capo ◽  
Alessandro Zappino ◽  
Amedeo Reyneri ◽  
Massimo Blandino
Keyword(s):  
Plant Growth ◽  
Grain Yield ◽  
Plant Density ◽  
Field Trials ◽  
Protective Effects ◽  
Seedling Mortality ◽  
Fusarium Spp ◽  
Maize Seeds ◽  
Seed Dressing ◽  
The Impact

Fusarium spp. are key pathogens in maize seeds and seedlings. The aim of this study has been to evaluate the effects of applying fungicides to maize seeds to increase the survival of seedlings and to enhance the early vigor and grain yield of the plants. The protective effects of 2-way (fludioxonil, metalaxil-M) and four-way (fludioxonil, metalaxil-M, azoxystrobin, thiabendazole) fungicide seed treatments were compared with an F. verticillioides seed infected control in 11 field trials carried out in North Italy. A second study focused on the impact F. verticillioides and F. graminearum seed-borne infection on plant growth and on the possible advantages of applying the previously reported seed dressing. The seed dressing increased the plant density, vigor during the whole vegetative growth cycle for all the production situations, and grain yield. F. verticillioides led to a higher seedling mortality than F. graminearum, while both species reduced plant growth and delayed the flowering date. Seed-borne infection has an important impact on both the population and vigor of maize plants. The four-way fungicide enhanced both the defense of the seedlings and the vigor of F. verticillioides infected plants, which in turn resulted in a significant improvement in grain yield, compared to a conventional two-way fungicide.

Efficacy of high seeding rates to increase grain yield of winter wheat and winter triticale in southern Alberta

2007 ◽  
Vol 87 (3) ◽  
pp. 503-507 ◽  
Author(s):  
Ross H McKenzie ◽  
Eric Bremer ◽  
Allan B Middleton ◽  
Pat G Pfiffner ◽  
Robert F Dunn ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Grain Yield ◽  
Plant Density ◽  
Stand Density ◽  
Seeding Rate ◽  
Winter Triticale ◽  
Southern Alberta ◽  
Plant Stand ◽  
The Impact

Field trials were conducted for 3 yr (2002/2003 to 2004/2005) at three locations in southern Alberta to determine the impact of seeding rate and opener type on plant stand and grain yield of winter wheat (Triticum aestivum L.) and winter triticale (× Triticosecale Wittmack). Responses were determined for an optimum date of seeding in early to mid-September and for a late seeding in early to mid-October. Conditions were generally favourable for crop establishment, winter survival and growth, and average site yields ranged from 4.5 to 8.9 Mg ha-1. The disc opener increased spring plant density by 12.5% compared with the hoe opener, but did not affect grain yield. Spring plant density was 23% lower for winter triticale than winter wheat and 20% lower for October-seeded cereals than September-seeded cereals. Late seeding reduced grain yields of winter wheat and winter triticale by an average of 18 and 11%, respectively. Increases in target seeding rates from 150 to 350 plants m-2 (approximately 70 to 160 kg ha-1) did not affect grain yield and quality of September-seeded cereals, but increased grain yield of late-seeded crops by an average of 5 kg per kg increase in seeding rate. High seeding rates did not fully compensate for yield losses caused by late seeding. Key words: Triticum aestivum, × Triticosecale, plant stand density, yield

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