Evaluation of seed, stem and soil applications of procymidone to control white rot (Sclerotium cepivorum Berk.) of onions

1991 ◽  
Vol 31 (3) ◽  
pp. 401 ◽  
Author(s):  
IJ Porter ◽  
JP Maughan ◽  
GB Towers
Keyword(s):  
Seed Treatment ◽  
Disease Incidence ◽  
Soil Surface ◽  
White Rot ◽  
Effective Control ◽  
Plant Establishment ◽  
Seed Treatments ◽  
Stem Base ◽  
Sclerotium Cepivorum ◽  
Plant Emergence

The effects of different methods of applying procymidone, either alone or combined, were evaluated for control of white rot (caused by Sclerotium cepivorum Berk.) in onions at 2 sites in Victoria.Field trials at Colac showed that seed treatments combined with sprays to the soil surface gave the most effective control of white rot, reducing disease from 78 to 16% and increasing yields from 5.7 to 14.6 t/ha in brown onions. Sprays applied to the soil surface at 2.5 kg a.i./ha had no effect on emergence and reduced disease incidence from 65.3 to 21.7%. Seed treatment at 25 g procymidone/kg seed delayed the onset of disease by 80 days and reduced disease incidence by 30%. The same treatment also reduced plant emergence by more than 27% and, therefore, did not increase yields. Dispersible granules (5 or 10%; at 2.5 kg procymidone/ha) were as effective as the soil sprays at sowing. Stem base sprays applied 11 and 19 weeks after sowing reduced disease incidence slightly but did not increase yields. Procymidone applied with bands of fertiliser 2 or 5 cm below the seed was not effective. Two formulations of procymidone, Sumisclex 500 (50% a.i.) and 275 Flocol (27.5% a.i.), were equally effective in controlling white rot. At Lang Lang, root-dips of 14-week-old seedlings in 5 g procymidone/L reduced white rot in transplanted white globe onions. Procymidone concentrations of 0.05-50 g a.i./L applied for periods ranging from 2 s to 30 min had no effect on plant establishment in a glasshouse.

scholarly journals Flavor Precursor [S-alk(en)yl-L-cysteine sulfoxide] Concentration and Composition in Onion Plant Organs and Predictability of Field White Rot Reaction of Onions

2005 ◽  
Vol 130 (2) ◽  
pp. 196-202 ◽  
Author(s):  
Marilyn H.Y. Hovius ◽  
Irwin L. Goldman ◽  
Kirk L. Parkin
Keyword(s):  
High Performance ◽  
Disease Incidence ◽  
Field Trials ◽  
White Rot ◽  
Individual Plant ◽  
Onion Plant ◽  
Plant Organs ◽  
Breeding Lines ◽  
Sclerotium Cepivorum ◽  
Cysteine Sulfoxide

Breeders have found field screening for white rot (Sclerotium cepivorum Berk.) resistance in onion (Allium cepa L.) to be unreliable since consistently moderate to high disease levels that significantly differentiate cultivars do not occur over field sites and years. The objective was to determine if differences in onion white rot resistance levels were associated with differing S-alk(en)yl-l-cysteine sulfoxide (ACSO) levels. A collection of onion breeding lines and hybrids were evaluated in field trials at six sites in 1999-2001. High performance liquid chromatography was used to analyze ACSOs in onion plant organs. Four main cysteine-sulfoxides exist in Allium L. species: methyl (MCSO), 2-propenyl (2-PeCSO), 1-propenyl (1-PeCSO), and propyl (PCSO). 1-PeCSO was predominant in onion leaves, bulbs, and roots. 2-PeCSO was found in trace amounts in onion leaves and roots. There was significantly more 2-PeCSO and total ACSO (roots only) and 1-PeCSO (roots and bulbs) in accessions that were more susceptible to white rot in the field trials. This is the first report of significant differences in ACSO contents among white rot susceptible and resistant onions. A covariance analysis was used to determine if the ACSO levels that significantly distinguished among accessions could predict field onion white rot reaction. 1-PeCSO from both roots and bulbs was the best predictor of field disease incidence in field sites that had low, moderate, and high disease levels. Although the ACSO concentrations were not assessed on an individual plant basis, breeders may be able to screen onions for resistance to S. cepivorum by comparing onion root or bulb 1-PeCSO levels based on the results from this research. White rot incidence in the field should be higher in those plants whose roots and bulbs have the highest levels of 1-PeCSO.

scholarly journals Polymerase Chain Reaction-Assisted Evaluation of the Efficacy of Seed-Treatment Prevention of Sporisorium reilianum Infection in Sorghum Seedlings

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhi Zhang ◽  
Juan Fan ◽  
Mucai Feng ◽  
Hongbo Qiu ◽  
Anlong Hu
Keyword(s):  
Polymerase Chain Reaction ◽  
Seed Treatment ◽  
Early Stage ◽  
Disease Incidence ◽  
Infected Plant ◽  
Seed Treatments ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Sporisorium Reilianum ◽  
Polymerase Chain

Head smut, caused by Sporisorium reilianum [(Kuhn) Langdon and Fullerton], is a major disease of sorghum. Seed treatment is considered to be the most effective way to control the disease; however, the pathogen can infect at the seedling stage and the infected plant will not display symptoms until the reproductive stage is reached. The evaluation of the efficacy of seed treatments is time consuming and is dependent upon visible symptoms. Polymerase chain reaction (PCR) methods have the ability to identify pathogens and diagnose their presence at an early stage of infection. In this study, the S. reilianum-specific primer SR3 was used for PCR detection pathogen. We optimized temperature, humidity, and spore quantity test conditions and were able to achieve >88% infection incidence in sorghum seedlings. Sorghum seeds were soaked in various concentrations of tebuconazole and planted for 7 days in soil containing 0.2% teliospores. The efficacy of tebuconazole against S. reilianum was evaluated by PCR and recorded as disease incidence. Results indicated that the reduction in disease incidence after exposure to 0.15, 0.30, 0.45, 0.60, and 0.75 μg/mL tebuconazole was 6.24, 37.48, 67.74, 81.24, and 93.74%, respectively. Significant differences between the concentrations of tebuconazole were observed. The PCR assay represents a valuable tool for evaluating the efficacy of fungicide seed treatments for the control of S. reilianum in sorghum under laboratory conditions.

scholarly journals Efficacy of Fungicide Seed Treatments in Controlling Blackleg of Canola

2019 ◽  
Vol 20 (3) ◽  
pp. 160-164
Author(s):  
Sudha GC Upadhaya ◽  
Venkataramana Chapara ◽  
Mukhlesur Rahman ◽  
Luis E. del Río Mendoza
Keyword(s):  
Seed Treatment ◽  
Leaf Growth ◽  
Disease Incidence ◽  
Leptosphaeria Maculans ◽  
Field Trials ◽  
Management Tool ◽  
Blackleg Disease ◽  
Seed Treatments ◽  
Spring Canola ◽  
Plant Stand

The efficacy of five fungicide seed treatments as a management tool against blackleg on spring canola was evaluated under greenhouse and field conditions in North Dakota. Blackleg, caused by Leptosphaeria maculans, inflicts the greatest yield losses when infecting seedlings before they reach the six-leaf growth stage. In greenhouse studies, 10-day-old seedlings were inoculated with L. maculans spore suspensions and evaluated 12 days later and at maturity or inoculated 12, 20, or 28 days after planting and evaluated at maturity. In field trials conducted in 2017 and 2018, severity was assessed at maturity. In the greenhouse, all fungicide seed treatments reduced (P = 0.05) disease severity at the seedling stage, but only the protection provided by Obvius (fluxapyroxad + pyraclostrobin + metalaxyl) and Helix Vibrance (mefenoxam + fludioxonil + sedaxane + difenoconazole + thiamethoxam) reduced (P < 0.05) severity at the adult stage; however, none of them provide effective protection when plants were inoculated 20 days after planting or later. In field trials, none of the treatments significantly (P > 0.05) improved plant stand and yield or reduced disease incidence and severity. Although fungicide seed treatment is a valuable tool, it should not be used as the only method to manage blackleg disease.

Field Screening for Onion White Rot Resistance

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534d-534
Author(s):  
Ronald Voss ◽  
Kent Brittan ◽  
Herb Phillips ◽  
Donald Kirby ◽  
W.Michael Davis ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Significant Loss ◽  
White Rot ◽  
Field Screening ◽  
Disease Expression ◽  
Sclerotium Cepivorum ◽  
Crop Resistance ◽  
Production Problem ◽  
Clean Seed ◽  
Rot Disease

Onion white rot disease (Sclerotium cepivorum) is a serious production problem throughout the world. Very low pathogen level in the soil can cause significant loss. Generic integrated pest management programs include clean seed, site selection, sanitation, crop rotation, biological and chemical controls, crop resistance to the pest, and other components. Onion white rot disease management currently does not have crop resistance as a component. The lack of resistant germplasm and/or the inability to identify and screen potentially resistant germplasm are primary reasons. Research was conducted to determine if field screening for resistance is feasible, to define field screening methodology, and to identify and/or quantify resistance. Disease incidence was inconsistent from year to year. In some years, disease expression was high; in others, disease was low. Uniform pathogen level and disease expression throughout the experimental field were required for successful screening. Results provide evidence that “resistant” or “tolerant” germplasm does exist, and that disease “resistance”, “tolerance”, or “susceptibility” can vary from slight to strong, suggesting multigenic involvement. “Resistance”/”tolerance” was identified in long-day yellow hybrids and inbreds. `Southport White Globe' selections and derivatives had much higher disease susceptibility than yellow or brown skin lines screened.

Effect of seed treatments on emergence, yield, and root rot severity of soybean under Rhizoctonia solani inoculated field conditions in Ontario

2007 ◽  
Vol 87 (1) ◽  
pp. 167-174 ◽  
Author(s):  
A. G. Xue ◽  
E. Cober ◽  
M. J. Morrison ◽  
H. D. Voldeng ◽  
B. L. Ma
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Seed Treatment ◽  
Bacillus Pumilus ◽  
Field Trials ◽  
Natural Soil ◽  
Seed Treatments ◽  
Untreated Seed ◽  
Plant Emergence ◽  
Better Than

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

FURTHER EXPERIMENTS ON CONTROL OF THE ONION MAGGOT, HYLEMYA ANTIQUA (MG.), IN THE INTERIOR OF BRITISH COLUMBIA

1957 ◽  
Vol 37 (3) ◽  
pp. 252-258 ◽  
Author(s):  
D. G. Finlayson
Keyword(s):  
British Columbia ◽  
Seed Treatment ◽  
Good Control ◽  
Soil Surface ◽  
Effective Control ◽  
Onion Maggot ◽  
Hylemya Antiqua ◽  
Wettable Powder ◽  
Degree Of Damage ◽  
High Yields

Experiments at two localities in the interior of British Columbia in 1952 and 1953 showed that a seed treatment of dieldrin at 0.5 oz. per pound of seed gave as good control of the onion maggot as any other treatment, was not phytotoxic, and gave the highest yield of marketable onions each year. Lindane, 25 per cent wettable powder, applied three times at 10-day intervals to the soil surface at 1 lb. of toxicant per acre per application gave consistently good control and high yields, but was more expensive in both labour and materials. Calomel at 1 lb. per pound of seed gave satisfactory control in a light infestation but cost twenty times as much as dieldrin. DDT at 8 oz. per pound of seed gave effective control but the bulk of insecticide on the seed caused jamming of the seeder. When the amount of DDT was reduced the degree of damage increased. Lindane as a seed treatment at 1 oz. per pound of seed was extremely phytotoxic. The same amount of aldrin applied in a similar manner was phytotoxic but to a lesser degree.

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