Effects of seed treatments and inoculum density of Fusarium avenaceum and Rhizoctonia solani on seedling blight and root rot of faba bean

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.

2019 ◽  
Vol 99 (2) ◽  
pp. 128-137 ◽  
Author(s):  
K.F. Chang ◽  
S.F. Hwang ◽  
R.L. Conner ◽  
H.U. Ahmed ◽  
Q. Zhou ◽  
...  

Soybean (Glycine max) acreage on the Canadian Prairies has increased rapidly in recent years. Production has expanded into semiarid regions where irrigation and drainage problems often result in the accumulation of salts in the soil. Fusarium avenaceum and Rhizoctonia solani are the two dominant pathogens in the disease complex that cause root rot and seedling blight of legume crops on the Canadian Prairies. The effects of F. avenaceum or R. solani in combination with soil salinity on soybean root rot were evaluated under greenhouse and mini-plot conditions. As expected, inoculation with F. avenaceum or R. solani consistently reduced seedling emergence and increased root rot severity in soybean. At high soil electrical conductivity values and inoculum densities, seedling emergence decreased and root rot severity increased in soybean in both trials with F. avenaceum and R. solani. Twenty short-season soybean cultivars that were well suited for production in Alberta were evaluated for their reactions to inoculation with F. avenaceum or R. solani in a saline soil (21.1 dS m−1). High seedling emergence was observed for cultivars 900Y61, P002T04R, 900Y01, TH27005RR, P001T34R, and 900Y81 in the non-inoculated control, for P002T04R and 900Y61 in the F. avenaceum treatment, and for 900Y61, 900Y81, and 900Y71 in the R. solani treatment. Root rot severity was low for cultivars NSC Portage and 900Y61 in the non-inoculated control and P002T004R in the F. avenaceum treatment. The cultivar 900Y61 also consistently had lower disease severity over the trials in the mini-plot test.


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 (4) ◽  
pp. 959-967 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
K. F. Chang ◽  
G. D. Turnbull ◽  
R. J. Howard ◽  
...  

Studies were undertaken to assess the impact of seedling blight and root rot caused by Rhizoctonia solani AG-4 on nodulation and seed yield of chickpea. The effects of pathogen inoculum concentration and seed damage on disease severity were also measured. Chickpea seedlings were grown under controlled-environment conditions in sterilized soil amended with pathogenic isolates of R. solani and in field plot experiments where the inoculum was incorporated with the seed at planting. In greenhouse experiments, emergence and dry matter production declined and root rot severity increased with increasing inoculum concentration. Root rot reduced nodulation where lesions covered more than 25% of the root surface. For chickpea cultivar Sanford this level of infection was sufficient to reduce root mass, but for the cultivar Tyson, more than half of the root was covered with lesions before root mass began to decline. In a comparison of seed treatment fungicides, thiram + carbathiin (Vitaflo 280) and carbathiin + thiabendazole (Crown at 6 mL of product kg-1 seed) significantly increased seedling emergence and seed yield compared to the inoculated control. In an assessment of the effects of seed damage, seedling survival and seed yield were similar for both healthy and mechanically damaged seed. Rhizoctonia solani has the potential to be an important constraint to chickpea production in the prairie region of western Canada. Key words: Rhizoctonia solani, Cicer arietinum, seed treatment, fungicide, seeding date


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


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.


2007 ◽  
Vol 87 (1) ◽  
pp. 167-174 ◽  
Author(s):  
A. G. Xue ◽  
E. Cober ◽  
M. J. Morrison ◽  
H. D. Voldeng ◽  
B. L. Ma

Field trials were conducted with soybean at two sites each year from 2001 to 2003 in Ottawa, ON, to determine the effect of seed treatments with various combinations of seven formulated fungicides and the bioagent Yield Shield (Bacillus pumilus GB34) under Rhizoctonia solani inoculated conditions. Controls were untreated seed planted into both non-inoculated (natural) soil and soil inoculated with R. solani. Compared with the non-inoculated control, inoculation significantly increased root rot severity and reduced emergence by 27%, and yield by 31%. Under the inoculated conditions, none of the seed treatments significantly increased emergence or yield in all of the six trials when compared with the control. Allegiance (metalaxyl) plus Vitaflo-280 (carbathiin plus thiram) and Vitaflo-280 alone were the most effective seed treatments, increasing emergence in by 20 and 19% and yield by 21 and 26%, which were significantly better than the control in four and five trials for emergence and three and four trials for yield, respectively. Allegiance plus HEC5725 (HEC5725), Apron Maxx RTA (fludioxonil plus metalaxyl), and Maxim 480FS (fludioxonil) increased both emergence and yield in two trials and TFL RTU (metalaxyl plus triflox ystrobin) plus Yield Shield in one trial. There was no difference between seed treatment with Allegiance and the untreated control for all parameters, confirming that metalaxyl is ineffective to R. solani. It is concluded that carbathiin, thiram, HEC5725, fludioxonil an trifloxystrobin are effective active ingredients protecting soybean from soil-borne R. solani and increasing plant emergence and yield. Key words: Rhizoctonia solani, seed treatment, soybean, Glycine max, fungicide, bioagent


2000 ◽  
Vol 80 (4) ◽  
pp. 899-907 ◽  
Author(s):  
S. F. Hwang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
K. F. Chang ◽  
R. J. Howard ◽  
...  

Early seeding of lentil is necessary on the northern prairies to ensure that the crop has time to mature. However, planting into cold soils in spring results in slow germination, which may predispose seedlings to infection by soil-borne pathogens. In a controlled-environment study of the impact of temperature on infection of lentil seedlings (cv. Eston) byFusarium avenaceum, root rot symptoms were most severe at warm temperatures (20° to 27.5 °C) and declined in warmer or cooler soils. Field plots were seeded on three dates, which were spaced about 2 wk apart between early May and early June in four station years. Seedling emergence was most consistent and seed yield was highest in three of four sites at the second seeding date. Emergence and yield were substantially lower for the latest seeding date. Inoculation with F. avenaceum reduced establishment and seed yield. Seed treatment with Crown (thiabendazole and carbathiin) improved seedling survival, reduced root rot severity and increased seed yield relative to the inoculated control. Vitaflo-280 (thiram and carbathiin) also improved establishment and yield, but the effect was not as strong or consistent. Treatment with Raxil (tebuconazole) and Apron (metalaxyl) had no effect. The pathogenicity of aggressive isolates of F. avenaceum from lentil on a range of crop species was evaluated. All crops were susceptible to some degree, which indicates that the pathogen, once established, is likely to persist in a field for some time. This study demonstrated that early planting was required for maximum yield, that certain isolates of F. avenaceum were pathogenic on a wide range of hosts, and that seed treatment can be used to minimize losses from seedling blight and root rot in lentil. Key words: Lentil (Lens culinaris Medikus), Fusarium avenaceum, root rot, seeding date, thiabendazole, carbathiin, thiram, tebuconazole


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.


2011 ◽  
Vol 91 (5) ◽  
pp. 859-872 ◽  
Author(s):  
K. F. Chang ◽  
S. F. Hwang ◽  
B. D. Gossen ◽  
S. E. Strelkov ◽  
G. D. Turnbull ◽  
...  

Chang, K. F., Hwang, S. F., Gossen, B. D., Strelkov, S. E., Turnbull, G. D. and Bing, D. J. 2011. Effect of seeding practices, temperature and seed treatments on fusarium seedling blight of narrow-leaved lupin. Can. J. Plant Sci. 91: 859–872. Narrow-leaved lupin (Lupinus angustifolius) has the potential to become an important pulse crop for the Canadian prairies because of its high protein content and adaptation to a short growing season. However, disease surveys conducted from 2003 to 2007 in Alberta revealed that the crop is vulnerable to seedling blight and root rot caused by Fusarium spp. In field trials, the incidence of seedling blight was reduced by the application of the seed treatment fungicides Apron Maxx RTA, Crown, and Vitaflo 280. Seeding in late May resulted in reduced seedling emergence compared with early or mid-May in some cases, but the results were not consistent. Yield was reduced in the late-sown crop. Seedling emergence was often higher from seed sown at a 2- to 5-cm depth compared with a 7- to 10-cm depth. Yield was lower at seeding rates of 150 seeds m−2 compared with 300 seeds m−2. Under controlled conditions, emergence was greatest in inoculated soils at 25/15°C (day/night). Optimum shoot growth occurred at this temperature and plants were stunted at both higher and lower temperatures. Root growth was greatest at 15/5°C in non-inoculated soils and declined with increasing temperature; root growth was lower, but less variable, among the temperatures in inoculated soils. Root rot severity rose and seed emergence declined with increasing concentration of Fusarium avenaceum inoculum. To successfully grow lupin crops, soils with low Fusarium concentrations must be chosen and the crop should be planted in areas where high temperatures are not common.


2003 ◽  
Vol 83 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A. G. Xue

The efficacy of seed treatments with bioagent ACM941 (a strain of Clonostachys rosea), its formulated products GB116 and ACM941-Pro, and common fungicides for the control of pea root rot complex were examined in six field trials in western Canada from 1996 to 2000. The effects on seedling emergence, root rot severity, and yield varied among years. In trials 1 and 2 (1996–1997), none of the treatments significantly reduced root rot severity or increased yield. ACM941 + Thiram 75WP was the most effective treatment, increasing emergence by 17.4% and was significantly better than that of the untreated controls. In trials 3 and 4 (1997–1998), Apron FL alone and ACM941 + Apron FL were significantly better than the untreated control, increasing emergence by 6.2 and 7.7%, and yield by 10.8 and 11.5%, respectively. In trials 5 and 6 (1999–2000), AC M 941 and GB116 were equally the most effective treatments, increasing emergence by 11.5 and 12.2%, and yield by 8.2 and 6.3%, respectively. These effects were significantly greater than that of the untreated control, but not significantly different from those of Apron FL or Vitaflo-280. ACM941-Pro was developed and tested in 2000 only, and it increased emergence by 17.1% and reduced root rot severity by 29.6%. Key words: Bioagent, Clonostachys rosea, field pea, Pisum sativum, pea root rot complex (PRRC), seed treatment, fungicide


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