Pythium, seedling disease of soybean and more…

2013 ◽  
Author(s):  
Martin Chilvers ◽  
Alejandro Rojas ◽  
Janette Jacobs ◽  
Alison Robertson ◽  
Rashelle Matthiesen-Andersen
Keyword(s):  
Seedling Disease

Rhizoctonia seedling disease of hemp and its control

1982 ◽  
Vol 1 (1) ◽  
pp. 111-113
Author(s):  
A.S. Al-Beldawi ◽  
Affaf Jawad ◽  
H.M. Sheik-Raddy
Keyword(s):  
Seedling Disease

STUDIES ON THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P.K. & B.

1956 ◽  
Vol 34 (4) ◽  
pp. 653-673 ◽  
Author(s):  
R. A. Ludwig ◽  
R. V. Clark ◽  
J. B. Julien ◽  
D. B. Robinson
Keyword(s):  
Disease Incidence ◽  
Infested Soil ◽  
Disease Development ◽  
Toxic Activity ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Nutrient Salt ◽  
Helminthosporium Sativum ◽  
Treatment Comparisons

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

scholarly journals Bacillus-based biological control of cotton seedling disease complex

2014 ◽  
Vol 54 (4) ◽  
pp. 340-348
Author(s):  
Mohammad Ahmed Khiyami ◽  
Moawad Ragab Omar ◽  
Kamel Ahmed Abd-Elsalam ◽  
Aly Abd El-Hady Aly
Keyword(s):  
Dry Weight ◽  
Damping Off ◽  
Single Strain ◽  
Seedling Disease ◽  
Cotton Seedling ◽  
Disease Complex ◽  
Fungal Isolates ◽  
Greenhouse Evaluation ◽  
Bacillus Spp ◽  
Bacillus Strains

Abstract To formulate an efficient and eco-friendly strategy for the management of cotton seedling disease complex, pot experiments were conducted and the efficiency of eight Bacillus strains against seven fungi involved in the disease were determined. A greenhouse evaluation of the interaction between fungal isolates and Bacillus strains was carried out. The evaluation revealed a very highly significant Bacillus strains x fungal isolates interaction for all the following parameters: preemergence damping-off, postemergence damping-off, survival, plant height, and dry weight. This interaction implies that a single strain of the Bacillus sp. can be highly effective against a fungal isolate, but may have only minimal effects on other fungal isolates. The results of the present study demonstrated that Bacillus circulans and B. coagulans were the most effective strains in controlling cotton seedling disease. Therefore, strains of Bacillus spp. should be tested against as many fungal isolates as possible. The testing will improve the chance of identifying Bacillus strains effective against several fungal isolates.

Comparison of North Carolina, Georgia, and Florida Isolates of Cylindrocladium parasiticum

1999 ◽  
Vol 26 (2) ◽  
pp. 80-84
Author(s):  
J. E. Hollowell ◽  
B. B. Shew ◽  
M. K. Beute
Keyword(s):  
North Carolina ◽  
Root Rot ◽  
Regional Differences ◽  
Black Rot ◽  
Temperature Growth ◽  
Seedling Disease ◽  
Cylindrocladium Parasiticum ◽  
Temperature Controlled ◽  
Gradient Plate ◽  
Temperature Optima

Abstract Thirteen isolates of Cylindrocladium parasiticum Crous, Wingfield & Alfenas from North Carolina and 11 from Georgia were grown on plates of PDA at 20,25, and 30 C on a temperature-gradient plate. Culture diameters were measured daily for 6 d. Significant differences were not observed among isolates grown at 20 C and cultures was smaller as compared with those grown at 25 and 30 C. At 25 and 30 C, isolates varied consistently in growth. On average, Georgia isolates grew slightly less than North Carolina isolates, and all isolates grew better at the warmer temperature. Growth of three North Carolina isolates was compared to four Florida isolates in a second experiment. Florida isolates grew significantly faster than North Carolina isolates at all temperatures. Isolates from the three states were compared for their ability to cause root rotting on peanut at 25 and 30 C. Plants were grown in soil infested at a standardized inoculum density in temperature-controlled water bath tanks for 7 wk at which time roots were rated for Cylindrocladium black rot development. Georgia isolates caused more root rot than either North Carolina or Florida isolates at both temperatures and also caused more seedling disease. State effects were significant; Florida isolates caused less root rot than Georgia isolates. Temperature by state interactions were not significant which means that high temperature-tolerant isolates of C. parasiticum have not evolved from regional differences in soil temperature. Further, North Carolina field isolates do not appear to have changed in temperature optima since the 1970s.

Gliovirin, a new antibiotic from Gliocladium virens, and its role in the biological control of Pythium ultimum

1983 ◽  
Vol 29 (3) ◽  
pp. 321-324 ◽  
Author(s):  
Charles R. Howell ◽  
Robert D. Stipanovic
Keyword(s):  
Pythium Ultimum ◽  
Similar Efficacy ◽  
Antibiotic Activity ◽  
Infested Soil ◽  
Damping Off ◽  
Potato Dextrose Broth ◽  
Seedling Disease ◽  
X Ray ◽  
Gliocladium Virens ◽  
Induced Mutant

A compound with antibiotic activity toward Pythium ultimum was isolated from potato dextrose broth shake cultures of Gliocladium virens, a common soil mycoparasite known to inhibit but not parasitize P. ultimum. The mass spectrum and an X-ray crystallograph of the purified antibiotic indicated that it was a new diketopiperazine, and we have given it the trivial name gliovirin. Gliovirin is highly toxic to P. ultimum but is inactive against other fungi associated with cotton seedling disease. The antibiotic does not persist in nonsterile soil where it is apparently inactivated by the soil microflora.An ultraviolet light induced mutant of G. virens deficient for gliovirin production was overgrown by P. ultimum in culture and did not protect cotton seedlings from damping-off in P. ultimum infested soil. A mutant with enhanced gliovirin production was more inhibitory to P. ultimum in culture than the parent isolate and showed similar efficacy as a seedling disease suppressant, even though its growth rate was reduced when compared to the parent isolate. These results indicate that gliovirin may be important to the antagonist–pathogen interaction.

Influence of spatial planting arrangement of winter rye cover crop on corn seedling disease and corn productivity

Plant Disease ◽  
2021 ◽  
Author(s):  
Sarah Maria Kurtz ◽  
Jyotsna Acharya ◽  
Thomas C. Kaspar ◽  
Alison E Robertson
Keyword(s):  
Cover Crop ◽  
Dry Weight ◽  
Winter Rye ◽  
Field Plot ◽  
Seedling Disease ◽  
Shoot Dry Weight ◽  
No Till ◽  
Clade B ◽  
Corn Seedling ◽  
On Farm

Despite numerous environmental benefits associated with cover crop (CC) use, some farmers are reluctant to include CCs in their production systems because of reported yield declines in corn. There are numerous potential reasons for this yield decline, including seedling disease. A winter rye CC can serve as a ‘green bridge’ for corn seedling pathogens. We hypothesized that proximity of corn seedling roots to decaying rye CC roots contributes to corn seeding disease. An experimental field plot and an on-farm study were conducted over two years to evaluate growth, development, and disease severity of corn seedlings planted at various distances from decaying winter rye CC plants. The experimental field plot study was conducted in a no-till corn-soybean rotation with five replications of a winter rye CC treatments seeded as (i) no CC control, (ii) broadcast, (iii) 19-cm drilled rows, and (iv) 76-cm drilled rows. The on-farm study was no-till corn-soybean rotation with four replications of a winter rye cover crop seeded as 38-cm drilled rows, 76-cm drilled rows, and no CC control. The corn was planted on 76-cm rows shortly after rye was terminated. With multiple seeding arrangements of winter rye, corn was planted at different distances from winter rye. Corn radicle root rot severity and incidence, shoot height, shoot dry weight, corn height and chlorophyll at VT, ear parameters, and yield were collected. Soil samples were taken in the corn row and the interrow at winter rye termination, corn planting, and corn growth stage V3 to estimate the abundance of Pythium clade B members present in soil samples. Our results showed that increased distance between winter rye residue and corn reduced seedling disease and Pythium clade B populations in the radicles and soil, and increased shoot dry weight, leaf chlorophyll, plant height, and yield. This suggests that physically distancing the corn crop from the winter rye CC is one way to reduce the negative effects of a winter rye CC on corn.

Effect of Seed Cleaning, Washing and Seed Treatment on Seedling Disease Incidence and Yield of Rice

2002 ◽  
Vol 5 (7) ◽  
pp. 767-769
Author(s):  
M. Asad-ud-do ◽  
M.K. Anam ◽  
Md. Nazrul Isl ◽  
M. Rahman ◽  
G.A. Fakir ◽  
...  
Keyword(s):  
Seed Treatment ◽  
Disease Incidence ◽  
Seedling Disease

Evaluation of bacteria isolated from rice for plant growth promotion and biological control of seedling disease of rice

2001 ◽  
Vol 47 (10) ◽  
pp. 916-924 ◽  
Author(s):  
Tika B Adhikari ◽  
C M Joseph ◽  
Guoping Yang ◽  
Donald A Phillips ◽  
Louise M Nelson
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Disease Incidence ◽  
Control Plant ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Bacterial Strains ◽  
Seedling Disease

Of 102 rhizoplane and endophytic bacteria isolated from rice roots and stems in California, 37% significantly (P [Formula: see text] 0.05) inhibited the growth in vitro of two pathogens, Achlya klebsiana and Pythium spinosum, causing seedling disease of rice. Four endophytic strains were highly effective against seedling disease in growth pouch assays, and these were identified as Pseudomonas fluorescens (S3), Pseudomonas tolaasii (S20), Pseudomonas veronii (S21), and Sphingomonas trueperi (S12) by sequencing of amplified 16S rRNA genes. Strains S12, S20, and S21 contained the nitrogen fixation gene, nifD, but only S12 was able to reduce acetylene in pure culture. The four strains significantly enhanced plant growth in the absence of pathogens, as evidenced by increases in plant height and dry weight of inoculated rice seedlings relative to noninoculated rice. Three bacterial strains (S3, S20, and S21) were evaluated in pot bioassays and reduced disease incidence by 50%–73%. Strain S3 was as effective at suppressing disease at the lowest inoculum density (106 CFU/mL) as at higher density (108 CFU/mL or undiluted suspension). This study indicates that selected endophytic bacterial strains have potential for control of seedling disease of rice and for plant growth promotion.Key words: biological control, plant growth promotion, endophytes, rice, seedling disease.

scholarly journals Sydowia polyspora is both a Foliar Endophyte and a Preemergent Seed Pathogen in Pinus ponderosa

Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 640-644 ◽  
Author(s):  
Mary Ridout ◽  
George Newcombe
Keyword(s):  
Pinus Ponderosa ◽  
Natural Regeneration ◽  
Seedling Recruitment ◽  
Tree Seedling ◽  
Tetrazolium Chloride ◽  
Seedling Disease ◽  
Viability Assay ◽  
Poor Seed ◽  
Series Of Experiments ◽  
Forest Nurseries

Poor seedling performance and reduced seed emergence are often ascribed to known pathogens that cause low seedling recruitment and poor seed emergence in forest nurseries and regeneration plantings. On the other hand, foliar endophytes are often overlooked as a source of poor emergence or tree seedling disease. Here, we show that an endophytic fungus common to the foliar microbiome of Pinus ponderosa acts as a cryptic pathogen in delaying emergence. In a series of experiments, we inoculated seed of P. ponderosa with a suspension of Sydowia polyspora 12 h prior to sowing. S. polyspora reduced seed emergence of its host, P. ponderosa, by as much as 30%. A tetrazolium chloride viability assay showed that S. polyspora reduces emergence by preventing germination; seed remained viable. In sum, pathogens affecting tree seed emergence and seedling recruitment may be endophytic as well as in seed and soil and deserve greater attention in studies of natural regeneration.

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