Effect of seeding date and depth, seed size and fungicide treatment on Fusarium and Pythium seedling blight of canola

2015 ◽  
Vol 95 (2) ◽  
pp. 293-301 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
G. D. Turnbull ◽  
B. D. Gossen ◽  
S. E. Strelkov

Hwang, S. F., Ahmed, H. U., Turnbull, G. D., Gossen, B. D. and Strelkov, S. E. 2015. Effect of seeding date and depth, seed size and fungicide treatment on Fusarium and Pythium seedling blight of canola. Can. J. Plant Sci. 95: 293–301. Seedling blight has a substantial impact on stand establishment and productivity of canola (Brassica napus) on the Canadian prairies. The effects of seeding date, seed size, seeding depth, and seed treatment fungicides on seedling blight of canola caused by Fusarium avenaceum and Pythium ultimum were evaluated under field conditions. In the trials inoculated with P. ultimum, early seeding reduced seedling emergence and seed yield in all 3 yr of the study. However, the interaction of F. avenaceum with seeding date was not consistent; inoculation with F. avenaceum reduced seedling emergence in early seeded canola in 1 of 4 yr, but emergence was higher in early than in mid-seeded treatments in 2 yr and there was no difference among seeding dates in 1 yr. Late seeding reduced seed yield in 2 of 4 yr in the F. avenaceum study. Seed size and seeding depth generally did not have an effect on seedling establishment or seed yield for either pathogen. Seed treatment with Helix Xtra (thiamethoxam+difenconazole+metalaxyl+fludioxonil) and Prosper FX (clothianidin+carboxin+trifloxystrobin+metalaxyl) fungicides increased seedling emergence and yield compared with the F. avenaceum-inoculated control. Seed treatment with Helix Xtra also increased seedling emergence and seed yield compared with the P. ultimum-inoculated control. Manipulation of seeding date did not substantially improve stand establishment or yield of canola when inoculum pressure was high. Seed treatment was the most effective strategy for reducing losses caused by seedling blight of canola in fields infested with F. avenaceum or P. ultimum.

2014 ◽  
Vol 94 (2) ◽  
pp. 311-321 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
G. D. Turnbull ◽  
B. D. Gossen ◽  
S. E. Strelkov

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.


2001 ◽  
Vol 81 (3) ◽  
pp. 509-517 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
K. F. Chang ◽  
G. D. Turnbull ◽  
R. J. Howard

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


2013 ◽  
pp. 150113084625001
Author(s):  
Sheau-Fang Hwang ◽  
Hafiz U. Ahmed ◽  
George D. Turnbull ◽  
Bruce Gossen ◽  
Stephen Strelkov

2014 ◽  
Vol 94 (4) ◽  
pp. 693-700 ◽  
Author(s):  
K. F. Chang ◽  
R. L. Conner ◽  
S. F. Hwang ◽  
H. U. Ahmed ◽  
D. L. McLaren ◽  
...  

Chang, K. F., Conner, R. L., Hwang, S. F., Ahmed, H. U., McLaren, D. L., Gossen, B. D. and Turnbull, G. D. 2014. Effects of seed treatments and inoculum density of Fusarium avenaceum and Rhizoctonia solani on seedling blight and root rot of faba bean. Can. J. Plant Sci. 94: 693–700. Production of faba bean cultivars with tannin-free seed on the Canadian prairies has potential for use in human food and as a feedstock for livestock and aquaculture. However, root rot is a major constraint to production. The effects of fungicide seed treatments on root rot caused by Fusarium avenaceum and Rhizoctonia solani, and the effect of inoculum density on seedling emergence, nodulation, root rot severity and yield of faba bean were examined across 12 station years from 2009 to 2011 at sites in Manitoba and Alberta. Fusarium avenaceum reduced seedling emergence more than R.solani, but both pathogens had a similar impact on seed yield. The effects of inoculum density and seed treatment were generally significant for seedling emergence, root rot severity and seed yield for both pathogens. The interaction effects of inoculum density×seed treatment for F.avenaceum and R.solani were only significant for seed yield and seedling emergence. Seedling emergence and seed yield declined with increasing inoculum level for both F. avenaceum and R.solani. Fungicidal seed treatments with Apron Maxx (fludioxonil+metalaxyl) and Vitaflo 280 (carbathiin+thiram) consistently improved emergence and seed yield in trials inoculated with F.avenaceum or R.solani. This study demonstrated that seed treatment to manage root rot of faba bean is warranted.


2007 ◽  
Vol 87 (1) ◽  
pp. 145-155 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
R. L. Conner ◽  
K. F. Chang ◽  
G. D. Turnbull ◽  
...  

Seedling blight can cause substantial reductions in stand density of field pea on the Canadian prairies. Ninety-four isolates of Rhizoctonia solani were obtained from soil samples collected from 37 pea fields in 1999 in Alberta, Canada. Sixty isolates were characterized as anastomosis group (AG)-4 and 12 isolates as AG-2-1. Some of these isolates caused severe pre-emergence damping-off and were classified as highly pathogenic; 41 of the 44 highly pathogenic isolates were AG-4 and three were AG-2-1. Two highly pathogenic AG-4 isolates were used to assess the effect of inoculum density on survival and growth of field pea seedlings, and the impact of seeding date, seeding depth, soil temperature, seed damage, seed treatments and seeding density on seedling blight and root rot injury. As inoculum density increased, so did root rot severity, while seedling establishment, shoot dry weight and root dry weight declined. Under controlled conditions, seedling establishment in the noninoculated control increased as soil temperatures increased, but establishment and growth declined in inoculated treatments. In a temperature gradient study, seedling infection was highest when mean daily temperatures were 17.5°C or higher. In field trials over 8 station years, delayed seeding often resulted in reduced seedling establishment in inoculated treatments, although this trend was not consistent across sites or years. Seed yield consistently declined with later seeding dates. Seed treatment with fungicides (carbathiin + thiram, metalaxyl) improved establishment and productivity in inoculated treatments, especially where seed was damaged prior to planting. Seeding depth had no impact on root rot severity. Emergence and seed yield increased with seeding density, but increasing density beyond 90 seeds m-2 did not result in proportionately higher yields. These results indicate that a combination of seed treatment and early seeding can reduce Rhizoctonia injury to pea seedlings under field conditions. Key words: Pisum sativum, Rhizoctonia solani (AG-4), management, seeding depth, seeding rate


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1110f-1110
Author(s):  
Nancy W. Callan ◽  
James B. Miller ◽  
Don E. Mathre

Shrunken-2 supersweet (sh2) sweet corn is susceptible to preemergence damping-off caused by Pythium ultimum, especially when planted into cold soil. Bio-priming, a seed treatment which combines the establishment of a bioprotectant on the seed with preplant seed hydration, was developed to protect seeds from damping-off.In a series of field experiments conducted in Montana's Bitterroot and Gallatin Valleys, bio-priming or seed bacterization with Pseudomonas fluorescens AB254 protected sweet corn from P. ultimum damping-off. Bio-priming corn seed with P. fluorescens AB254 was comparable to treatment with the fungicide metalaxyl in increasing seedling emergence. Seedlings from bio-primed seeds emerged from the soil more rapidly than from nontreated seeds and were larger at three weeks postplanting. Seeds of sh 2 and sugary enhancer (se) sweet corn, as well as that of several sh 2 cultivars, were protected from damping-off by bio-priming.


2000 ◽  
Vol 22 (4) ◽  
pp. 392-399 ◽  
Author(s):  
S.F. Hwang ◽  
B.D. Gossen ◽  
G.D. Turnbull ◽  
K.F. Chang ◽  
R.J. Howard ◽  
...  

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 535-537 ◽  
Author(s):  
K. E. Conway ◽  
R. Mereddy ◽  
B. A. Kahn ◽  
Y. Wu ◽  
S. W. Hallgren ◽  
...  

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.


2008 ◽  
Vol 88 (4) ◽  
pp. 799-809 ◽  
Author(s):  
K. F. Chang ◽  
S. F. Hwang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
H. Wang ◽  
...  

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


2003 ◽  
Vol 83 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Y. T. Gan ◽  
P. R. Miller ◽  
C. L. McDonald

The use of small seed can reduce the production costs of kabuli chickpea (Cicer arietinum L.) 15 to 25% by reducing the amount of seed needed per unit area, but little is known about the effects of seed size on stand establishment, plant growth, and seed yield in semiarid environments. We conducted a field study in southwest Saskatchewan from 1998 to 2000 and determined the chickpea responses to seed size under different planting depths. Crops grown from small (7.1–9.0 mm) diameter seed required the same number of days to emerge (16.7 d) and mature (106 d) as those from large (9.1–11.0 mm) diameter seed. There were no differences in plant establishment, shoot dry weight, pod production, or seed yield between the two seed sizes when planted at a 50-mm depth. However, the small-seeded crop produced 7% lower plant stand, 4% lower seed yield, and 3% less seed 1799-mm diameter compared to the large-seeded crop when planted at a 100-mm depth (P < 0.05). Large-seed ed chickpea plants were 20 mm (4%) taller, and the height of the lowest pods from the soil surface was 11 to 13 mm (5%) higher than those from the small seed, suggesting an improvement of harvestability. In general, planting depth did not affect seedling emergence, shoot dry weight, or seed yield, but when small seed was used, chickpea sown at the 50-mm depth increased seed yield by 6% compared to that at the 100-mm depth. Kabuli chickpea produced an average of >20 pods plant-1, with 77% of them containing one seed per pod, 10% with two seeds per pod, and the remainder containing no seed; this ratio of pod fertility was independent of seed size or planting depth. Our results indicate that the use of small seed and shallow planting can reduce the production costs of chickpea by $31 to $52 ha-1 without a seed yield penalty. This level of saving in production far exceeds the otherwise increased value of $4 to $6 ha-1 with the use of large seed which produces a higher (3%) proportion of ≥ 9-mm diameter seed. Key words: Seedling emergence, seed mass, pod production, Cicer arietinum L.


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