scholarly journals Importance of Fungicide Seed Treatment and Environment on Seedling Diseases of Cotton

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1805-1817 ◽  
Author(s):  
C. S. Rothrock ◽  
S. A. Winters ◽  
P. K. Miller ◽  
E. Gbur ◽  
L. M. Verhalen ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Rhizoctonia Solani ◽  
Seed Treatment ◽  
Significant Response ◽  
Seed Treatments ◽  
Seedling Disease ◽  
Stand Establishment ◽  
Disease Complex ◽  
Soil Temperatures ◽  
Seedling Pathogens

The importance of fungicide seed treatments on cotton was examined using a series of standardized fungicide trials from 1993 to 2004. Fungicide seed treatments increased stands over those from seed not treated with fungicides in 119 of 211 trials. Metalaxyl increased stands compared to nontreated seed in 40 of 119 trials having significant fungicide responses, demonstrating the importance of Pythium spp. on stand establishment. Similarly, PCNB seed treatment increased stands compared to nontreated seed for 44 of 119 trials with a significant response, indicating the importance of Rhizoctonia solani in stand losses. Benefits from the use of newer seed treatment chemistries, azoxystrobin and triazoles, were demonstrated by comparison with a historic standard seed treatment, carboxin + PCNB + metalaxyl. Little to no stand improvement was found when minimal soil temperatures averaged 25°C the first 3 days after planting. Stand losses due to seedling pathogens increased dramatically as minimal soil temperatures decreased to 12°C and rainfall increased. The importance of Pythium increased dramatically as minimal soil temperature decreased and rainfall increased, while the importance of R. solani was not affected greatly by planting environment. These multi-year data support the widespread use of seed treatment fungicides for the control of the seedling disease complex on cotton.

scholarly journals Effect of Seed Quality and Combination Fungicide-Trichoderma spp. Seed Treatments on Pre- and Postemergence Damping-Off in Cotton

2007 ◽  
Vol 97 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Charles R. Howell
Keyword(s):  
Rhizoctonia Solani ◽  
Seed Treatment ◽  
Seed Quality ◽  
Rhizopus Oryzae ◽  
Poor Quality ◽  
Infested Soil ◽  
Damping Off ◽  
Seed Treatments ◽  
Trichoderma Spp ◽  
Seedling Disease

Good quality seeds of cotton cultivars often escaped pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae, and they were resistant to postemergence damping-off incited by Rhizoctonia solani. Poor quality seeds, however, were highly susceptible to both phases of seedling disease and required seed treatment in order to survive. Pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae could be controlled by seed treatment with biocontrol preparations of a number of Trichoderma spp., but these treatments were much less effective in controlling postemergence disease incited by Rhizoctonia solani. Postemergence seedling disease can be controlled by fungicides, but they were much less effective in controlling the pre-emergence phase of the disease. Combination seed treatments of poor quality cotton seeds with fungicides and Trichoderma spp. preparations, followed by planting in pathogen-infested soil, indicated that this technique will control both phases of seedling disease. Seed treatment with either the fungicides or the biocontrol agents alone did not achieve this goal. The optimum combination treatment for disease control was that of chloroneb plus Trichoderma spp., followed by chloroneb plus metalaxyl (Deltacoat AD) plus T. virens strain G-6.

scholarly journals PRAIRIE GRASS ESTABLISHMENT AFFECTED BY SEED TREATMENT AND SOWING DATE

1985 ◽  
pp. 141-146
Author(s):  
R.E. Falloon
Keyword(s):  
Seedling Establishment ◽  
Seed Treatment ◽  
Sowing Date ◽  
Seed Treatments ◽  
Head Smut ◽  
Sowing Dates ◽  
Prairie Grass ◽  
Soil Temperatures ◽  
Successful Establishment ◽  
Grass Establishment

Effects of two different fungicide seed treatments, inoculation of seed with teliospores of the head smut fungus (Ustilago bullata Berk.), and five different autumn sowing dates, on establishment of prairie grass (Bromus willdenowii Kunth cv. 'Grasslands Matua,'), were examined in a field trial. Seedling establishment was increased by thiram seed treatment and decreased by inoculation of seed with U. bullata. Greater numbers of seedlings established from early sowings, when soil temperatures were higher, than from late sowings. Suitable seed treatments to increase the likelihood of successful establishment of prairie grass are discussed. Keywords: Bromus willdenowii, seedling establishment, seed treatments, thiram, Ustilago bullata, sowing dates, soil temperatures

A Fungicide Application Decision (FAD) Support System for Postbloom Fruit Drop of Citrus (PFD)

2002 ◽  
Vol 3 (1) ◽  
pp. 16 ◽  
Author(s):  
Natália A. R. Peres ◽  
Soonho Kim ◽  
Howard W. Beck ◽  
Nilton L. Souza ◽  
Lavern W. Timmer
Keyword(s):  
Rhizoctonia Solani ◽  
Support System ◽  
Thielaviopsis Basicola ◽  
Seedling Disease ◽  
Cotton Seedling ◽  
Fungicide Application ◽  
Disease Complex ◽  
Fruit Drop ◽  
Application Decision ◽  
Seedling Diseases

Surveys were conducted to identify fungi associated with postemergence cotton seedling disease in Missouri. Samples consisted of 10 cotton seedlings, 2 to 3 weeks after emergence, with symptoms of seedling diseases collected from a 0.25 ha area in each of 60 fields in 1997 and 1998. Four genera of fungi were cultured from the roots (Fusarium, Pythium, Rhizoctonia, and Thielaviopsis) and three species were identified: Rhizoctonia solani, Thielaviopsis basicola, and Pythiumultimum. Rhizoctonia solani, T. basicola, and P. ultimum were cultured from seedlings in 70%, 47%, and 15% of fields sampled in 1997, respectively, and 55%, 17%, and 5% of fields sampled in 1998, respectively. Repeated tests of pathogenicity confirmed that R. solani AG-4, T. basicola, and P. ultimum were major causal agents of postemergence cotton seedling disease in Missouri. This study provides the first documentation on the distribution and frequency of fungi associated with postemergence seedling disease complex of cotton based on a survey of randomly selected fields. Accepted for publication 10 July 2002. Published 31 July 2002.

scholarly journals The Efficacy of Ethaboxam as a Soybean Seed Treatment Toward Phytophthora, Phytopythium, and Pythium in Ohio

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1421-1432 ◽  
Author(s):  
Kelsey Scott ◽  
Meredith Eyre ◽  
Dair McDuffee ◽  
Anne E. Dorrance
Keyword(s):  
Seed Treatment ◽  
Soybean Seed ◽  
Primary Objective ◽  
Phytophthora Species ◽  
Damping Off ◽  
Seed Treatments ◽  
Seedling Disease ◽  
Seed Decay ◽  
Fungicide Mixtures ◽  
Seed Rot

Phytophthora, Phytopythium, and Pythium species that cause early-season seed decay and pre-emergence and post-emergence damping off of soybean are most commonly managed with seed treatments. The phenylamide fungicides metalaxyl and mefenoxam, and ethaboxam are effective toward some but not all species. The primary objective of this study was to evaluate the efficacy of ethaboxam in fungicide mixtures and compare those with other fungicides as seed treatments to protect soybean against Pythium, Phytopythium, and Phytophthora species in both high-disease field environments and laboratory seed plate assays. The second objective was to evaluate these seed treatment mixtures on cultivars that have varying levels and combinations of resistance to these soilborne pathogens. Five of eight environments received adequate precipitation in the 14 days after planting for high levels of seedling disease development and treatment evaluations. Three environments had significantly greater stands, and three had significantly greater yield when ethaboxam was used in the seed treatment mixture compared with treatments containing metalaxyl or mefenoxam alone. Three fungicide formulations significantly reduced disease severity compared with nontreated in the seed plate assay for 17 species. However, the combination of ethaboxam plus metalaxyl in a mixture was more effective than either fungicide alone against some Pythium and Phytopythium species. Overall, our results indicate that the addition of ethaboxam to a fungicide seed treatment is effective in reducing seed rot caused by these pathogens commonly isolated from soybean in Ohio but that these effects can be masked when cultivars with resistance are planted.

Fungi Associated With Postemergence Cotton Seedling Disease in Missouri

2002 ◽  
Vol 3 (1) ◽  
pp. 7 ◽  
Author(s):  
J. A. Wrather ◽  
B. Phipps ◽  
C. S. Rothrock
Keyword(s):  
Rhizoctonia Solani ◽  
Thielaviopsis Basicola ◽  
Seedling Disease ◽  
Cotton Seedling ◽  
Disease Complex ◽  
Seedling Diseases

Surveys were conducted to identify fungi associated with postemergence cotton seedling disease in Missouri. Samples consisted of 10 cotton seedlings, 2 to 3 weeks after emergence, with symptoms of seedling diseases collected from a 0.25 ha area in each of 60 fields in 1997 and 1998. Four genera of fungi were cultured from the roots (Fusarium, Pythium, Rhizoctonia, and Thielaviopsis) and three species were identified: Rhizoctonia solani, Thielaviopsis basicola, and Pythiumultimum. Rhizoctonia solani, T. basicola, and P. ultimum were cultured from seedlings in 70%, 47%, and 15% of fields sampled in 1997, respectively, and 55%, 17%, and 5% of fields sampled in 1998, respectively. Repeated tests of pathogenicity confirmed that R. solani AG-4, T. basicola, and P. ultimum were major causal agents of postemergence cotton seedling disease in Missouri. This study provides the first documentation on the distribution and frequency of fungi associated with postemergence seedling disease complex of cotton based on a survey of randomly selected fields. Accepted for publication 9 July 2002. Published 22 July 2002.

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

scholarly journals Infection of Soybean Seed by Fusarium graminearum and Effect of Seed Treatments on Disease Under Controlled Conditions

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 401-407 ◽  
Author(s):  
M. L. Ellis ◽  
K. D. Broders ◽  
P. A. Paul ◽  
A. E. Dorrance
Keyword(s):  
Fusarium Graminearum ◽  
Seed Treatment ◽  
Soybean Seed ◽  
Disease Development ◽  
Damping Off ◽  
Optimum Conditions ◽  
Seed Treatments ◽  
Seedling Disease ◽  
Seed Decay ◽  
Recent Emergence

Fusarium graminearum causes seed decay and damping-off of soybean. This study evaluated the effect of inoculum density of F. graminearum, temperature, and fungicide seed treatments on disease development. To determine the optimum conditions for disease development, individual soybean seed was inoculated with 100 μl of a suspension of 2.5 × 102, 2.5 × 103, 2.5 × 104, or 2.5 × 105 macroconidia/ml in a rolled-towel assay at temperatures of 18, 22, and 25°C. Inoculum concentrations of 2.5 × 104 macroconidia/ml or higher were necessary for optimum disease development at all temperatures. The efficacy of captan, fludioxonil, mefenoxam + fludioxonil, azoxystrobin, trifloxystrobin, and pyraclostrobin as seed treatments was then evaluated with the same assay at 2.5 × 104 and 2.5 × 105 macroconidia/ml. Seed treated with captan at 61.9 g a.i. or fludioxonil at 2.5 or 5.0 g a.i. per 100 kg developed smaller lesions than other seed treatments and the nontreated control. Based on these results, there are limited choices in fungicide seed treatments for managing this seedling disease, and it is possible that shifts in seed treatment products may have played a role in the recent emergence of this soybean pathogen.

scholarly journals Emergence of Sugar Beet Seedlings at Low Soil Temperature following Seed Soaking and Priming

HortScience ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 31-32 ◽  
Author(s):  
Glen Murray ◽  
Jerry B. Swensen ◽  
John J. Gallian
Keyword(s):  
Polyethylene Glycol ◽  
Sugar Beet ◽  
Soil Temperature ◽  
Beta Vulgaris ◽  
Seed Treatment ◽  
Laboratory Experiments ◽  
Seedling Emergence ◽  
Field Soil ◽  
Low Field ◽  
Soil Temperatures

Seedling emergence from primed and nonprimed sugar beet seed (Beta vulgaris L.) was studied for 3 years under field conditions near Kimberly, Idaho, and compared with germination or emergence under controlled laboratory conditions. Maximum seedling emergence did not vary with seed treatment in spite of low field soil temperatures. Time to 50% of maximum emergence was significantly less for seed primed with polyethylene glycol 8000 than for nonprimed seed in only 1 of 3 years. Seed soaked in 30C water for 24 h performed similarly to nontreated seed in the field, but their maximum emergence was significantly improved compared with primed seed in one of two laboratory experiments. Time to 50% of maximum germination was improved by priming with or without a warm water soak in one of the two laboratory experiments.

scholarly journals Seed Treatment Effects on Maize Seedlings Coinfected with Rhizoctonia solani and Pratylenchus penetrans

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 957-963 ◽  
Author(s):  
M. P. da Silva ◽  
G. L. Tylka ◽  
G. P. Munkvold
Keyword(s):  
Rhizoctonia Solani ◽  
Root Development ◽  
Seed Treatment ◽  
Growth Chamber ◽  
Pratylenchus Penetrans ◽  
Maize Seedlings ◽  
Seed Treatments ◽  
Sand Soil ◽  
Soil Mixture ◽  
Greenhouse Experiments

The roots of maize seedlings typically are attacked by a complex of organisms that includes fungal pathogens and plant-parasitic nematodes but few studies have examined the effects of these organisms in combination. Rhizoctonia solani can be an important component of the seedling disease complex; like other fungi, its effect on the plant may be influenced by the activity of nematodes such as the root-lesion nematode Pratylenchus penetrans. In this study, we assessed the impact of seed treatments, including fungicide–nematicide combinations, on maize seedlings exposed to R. solani and P. penetrans alone or in combination. In growth-chamber and greenhouse experiments, seed treated with various active ingredient combinations were planted in an autoclaved sand-soil mixture with or without inoculum of R. solani. In some treatments, a suspension of P. penetrans adults and juveniles was added to the sand-soil mixture. In the greenhouse experiments, infection by R. solani caused dramatic reductions in root length, volume, surface area, and numbers of root tips and root forks, whereas P. penetrans infestation alone reduced only shoot fresh weight. Statistical interactions between the effects of the two organisms were not significant, although fungal infestation significantly reduced the numbers of nematodes extracted from roots. Seed treatments significantly improved most root development variables, and the combination that included four fungicides, thiamethoxam, and abamectin was the best treatment for most variables. Results were similar in the growth-chamber experiments, where R. solani caused significant reductions in nearly all shoot and root development measurements, and seed treatment with sedaxane, alone or combined with abamectin, consistently provided the best results. R. solani was more damaging to seedlings than P. penetrans, and the combination of the two organisms did not cause more damage than R. solani alone. Seed-treatment active ingredients that specifically targeted R. solani (sedaxane) and P. penetrans (abamectin) had large positive effects on seedling health, causing significant improvements in root and shoot growth and development compared with untreated seedlings exposed to these pathogens.

scholarly journals Induction of Terpenoid Synthesis in Cotton Roots and Control of Rhizoctonia solani by Seed Treatment with Trichoderma virens

2000 ◽  
Vol 90 (3) ◽  
pp. 248-252 ◽  
Author(s):  
C. R. Howell ◽  
L. E. Hanson ◽  
R. D. Stipanovic ◽  
L. S. Puckhaber
Keyword(s):  
Biological Control ◽  
Rhizoctonia Solani ◽  
Seed Treatment ◽  
Antibiotic Production ◽  
Defense Responses ◽  
Control Analysis ◽  
Trichoderma Virens ◽  
Seedling Disease ◽  
Treated Seed ◽  
And Control

Research on the mechanisms employed by the biocontrol agent Trichoderma virens to suppress cotton (Gossypium hirsutum) seedling disease incited by Rhizoctonia solani has shown that mycoparasitism and antibiotic production are not major contributors to successful biological control. In this study, we examined the possibility that seed treatment with T. virens stimulates defense responses, as indicated by the synthesis of terpenoids in cotton roots. We also examined the role of these terpenoid compounds in disease control. Analysis of extracts of cotton roots and hypocotyls grown from T. virens-treated seed showed that terpenoid synthesis and peroxidase activity were increased in the roots of treated plants, but not in the hypocotyls of these plants or in the untreated controls. Bioassay of the terpenoids for toxicity to R. solani showed that the pathway intermediates desoxyhemigossypol (dHG) and hemigossypol (HG) were strongly inhibitory to the pathogen, while the final product gossypol (G) was toxic only at a much higher concentration. Strains of T. virens and T. koningii were much more resistant to HG than was R. solani, and they thoroughly colonized the cotton roots. A comparison of biocontrol efficacy and induction of terpenoid synthesis in cotton roots by strains of T. virens, T. koningii, T. harzianum, and protoplast fusants indicated that there was a strong correlation (+0.89) between these two phenomena. It, therefore, appears that induction of defense response, particularly terpenoid synthesis, in cotton roots by T. virens may be an important mechanism in the biological control by this fungus of R. solani-incited cotton seedling disease.

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