scholarly journals Damping-off of sugar beet with special reference to the fungus Pythium Pringsheim

1988 ◽  
Vol 60 (3) ◽  
pp. 159-178
Author(s):  
M. Vestberg
Keyword(s):  
Sugar Beet ◽  
High Temperatures ◽  
Seed Treatment ◽  
Disease Incidence ◽  
Fusarium Species ◽  
Systemic Fungicide ◽  
Second Phase ◽  
Damping Off ◽  
Short Term ◽  
Preceding Crop

In Finland damping-off of sugar beet can be divided into two distinct phases. The first phase begins with the germination of the seeds and continues until the first true leaves have developed. Under field conditions seedlings usually remain healthy up to about 1 week after emergence. Thereafter a sudden outbreak of damping-off may occur, resulting in rapid wilting and death of seedlings. During the second phase of the disease, when seedlings have one or more pairs of true leaves, disease does not always result in the death of the plant; plants may survive throughout the summer. At the pernicious phase of the disease the soil borne pathogen, Pythium debaryanum auct. non Hesse, is the most common causal agent, accounting in 1979—86 for 53.9 % (variation between years 18.3—90.1 %) of fungal isolations, and Fusarium species for 28.3 % (5.0—58.5 %). At seedling stages with one or more pairs of true leaves Fusarium spp. predominate accounting for 49.4 % (36.1—81.0 %) as compared to 23,9 % (2.9—37.8) for P. debaryanum. The importance of Fusarium species as true damping-off pathogens is, however, doubtful. The seed borne damping-off pathogen Phoma betae Frank was isolated only in 0 to 4 % and was not dependent on the stage of seedling development. Of the factors affecting damping-off, high temperatures were repeatedly shown to increase the disease. This, presumably was an effect especially on P. debaryanum, the aggressiveness of which is strongly increased at high temperatures. Pot experiments showed preceding crops of cereals to have the best disease-decreasing effect, both short-term (one growing period of preceding crop) and long-term (several growing periods of preceding crop) effect. Legumes kept the level of damping-off unchanged or even raised it, especially as a short-term effect. The influence of preceding crops varied in different soil types. Preceding crops also caused considerable fluctuations in inoculum density (0 to 3650 propagules/gram soil) and potential (0.2—16 IPU 50/gram soil) of Pythium. The correlation to damping-off of sugar beet was, however, poor. Seed treatment with the systemic fungicide hymexazol, especially when combined with thiram, prevented satisfactorily the pernicious type of damping-off. In many experiments this seed treatment repeatedly decreased disease incidence significantly, produced denser stands (7100—31200 numbers of beets more/hectare) and increased yield by 5—10 % on average.

Biological control of damping-off of sugar-beet and cotton with Chaetomium globosum or a fluorescent Pseudomonas sp.

1988 ◽  
Vol 34 (5) ◽  
pp. 631-637 ◽  
Author(s):  
D. Walther ◽  
D. Gindrat
Keyword(s):  
Biological Control ◽  
Sugar Beet ◽  
Seed Treatment ◽  
Pythium Ultimum ◽  
Chaetomium Globosum ◽  
Pseudomonas Sp ◽  
Damping Off ◽  
Antifungal Metabolites ◽  
Fluorescent Pseudomonas

Seed treatment with ascospores of Chaetomium globosum reduced damping-off of sugar-beet caused by seed-borne Phoma betae and soil-borne Pythium ultimum or Rhizoctonia solani in growth chamber experiments. Seed treatment with a fluorescent Pseudomonas sp. controlled Ph. betae and P. ultimum but not R. solani. Coating cotton seeds with ascospores controlled P. ultimum and R. solani damping-off. In some experiments, biological seed treatments were equally or more effective than seed treatment with captan. However, greater variability in disease control occurred with the antagonists than with captan. Fifty percent of freshly harvested ascospores of C. globosum germinated in 8 h on water agar. When ascospores were stored under air-dried conditions for 3 days to 2.5 years, germination increased to > 90%. Under same storage conditions, survival of Pseudomonas sp. was detected after 4 months. Antagonistic activities observed in vitro were hyphal coiling of C. globosum on R. solani, and mycostasis was induced by C. globosum or Pseudomonas sp. on agar and soil. The presumed cause of mycostasis is the diffusible antifungal metabolites which may also be involved in the biological control of damping-off.

scholarly journals First Report on Ovate-leaf Atractylodes Damping-off Caused by Fusarium oxysporum species Complex in South Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Oliul Hassan ◽  
Taehyun Chang
Keyword(s):  
South Korea ◽  
Fusarium Oxysporum ◽  
Species Complex ◽  
Disease Incidence ◽  
Fusarium Species ◽  
Morphological Characteristics ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Damping Off ◽  
First Report

In South Korea, ovate-leaf atractylodes (OLA) (Atractylodes ovata) is cultivated for herbal medicine. During May to June 2019, a disease with damping off symptoms on OLA seedlings were observed at three farmer fields in Mungyeong, South Korea. Disease incidence was estimated as approximately 20% based on calculating the proportion of symptomatic seedlings in three randomly selected fields. Six randomly selected seedlings (two from each field) showing damping off symptoms were collected. Small pieces (1 cm2) were cut from infected roots, surface-sterilized (1 minute in 0.5% sodium hypochlorite), rinsed twice with sterile water, air-dried and then plated on potato dextrose agar (PDA, Difco, and Becton Dickinson). Hyphal tips were excised and transferred to fresh PDA. Six morphologically similar isolates were obtained from six samples. Seven-day-old colonies, incubated at 25 °C in the dark on PDA, were whitish with light purple mycelia on the upper side and white with light purple at the center on the reverse side. Macroconidia were 3–5 septate, curved, both ends were pointed, and were 19.8–36.62 × 3.3–4.7 µm (n= 30). Microconidia were cylindrical or ellipsoid and 5.5–11.6 × 2.5–3.8 µm (n=30). Chlamydospores were globose and 9.6 –16.3 × 9.4 – 15.0 µm (n=30). The morphological characteristics of present isolates were comparable with that of Fusarium species (Maryani et al. 2019). Genomic DNA was extracted from 4 days old cultures of each isolate of SRRM 4.2, SRRH3, and SRRH5, EF-1α and rpb2 region were amplified using EF792 + EF829, and RPB2-5f2 + RPB2-7cr primer sets, respectively (Carbone and Kohn, 1999; O'Donnell et al. 2010) and sequenced (GenBank accession number: LC569791- LC569793 and LC600806- LC600808). BLAST query against Fusarium loci sampled and multilocus sequence typing database revealed that 99–100% identity to corresponding sequences of the F. oxysporum species complex (strain NRRL 28395 and 26379). Maximum likelihood phylogenetic analysis with MEGA v. 6.0 using the concatenated sequencing data for EF-1α and rpb2 showed that the isolates belonged to F. oxysporum species complex. Each three healthy seedlings with similar sized (big flower sabju) were grown for 20 days in a plastic pot containing autoclaved peat soil was used for pathogenicity tests. Conidial suspensions (106 conidia mL−1) of 20 days old colonies per isolate (two isolates) were prepared in sterile water. Three pots per strain were inoculated either by pouring 50 ml of the conidial suspension or by the same quantity of sterile distilled water as control. After inoculation, all pots were incubated at 25 °C with a 16-hour light/8-hour dark cycle in a growth chamber. This experiment repeated twice. Inoculated seedlings were watered twice a week. Approximately 60% of the inoculated seedlings per strain wilted after 15 days of inoculation and control seedlings remained asymptomatic. Fusarium oxysporum was successfully isolated from infected seedling and identified based on morphology and EF-1α sequences data to confirm Koch’s postulates. Fusarium oxysporum is responsible for damping-off of many plant species, including larch, tomato, melon, bean, banana, cotton, chickpea, and Arabidopsis thaliana (Fourie et al. 2011; Hassan et al.2019). To the best of our knowledge, this is the first report on damping-off of ovate-leaf atractylodes caused by F. oxysporum in South Korea. This finding provides a basis for studying the epidemic and management of the disease.

scholarly journals Damping-off of sugar beet in Finland: I. Causal agents and some factors affecting the disease

1982 ◽  
Vol 54 (4) ◽  
pp. 225-244
Author(s):  
Mauritz Vestberg ◽  
Risto Tahvonen ◽  
Kyösti Raininko
Keyword(s):  
Sugar Beet ◽  
Fusarium Species ◽  
Damping Off ◽  
Fusarium Spp ◽  
Factors Affecting ◽  
Pathogenicity Tests ◽  
Phoma Betae

The fungus Pythium debaryanum auct. non Hesse is the main cause of damping-off on sugar beet in Finland. The fungus is found especially in diseased seedlings during the first two weeks after emergence. Later on, when the plants have one or two pairs of true leaves, Fusarium spp. can be isolated to a rather great extent. However, pathogenicity tests with three different Fusarium species have shown that this fungus is unble cause damping-off on sugar beet when inoculated into peat substrate. Among the fungi tried in this respect, only Pythium debaryanum and Phoma betae Frank showed clear pathogenicity. Sugar beet seedlings that outlive the disease grow slower, and their quality at harvest in the autumn is poorer than that of healthy beets.

scholarly journals First Report of Sugar Beet Seedling Damping-Off Caused by Binucleate Rhizoctonia AG-A in China

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1696-1696 ◽  
Author(s):  
P. P. Wang ◽  
X. H. Wu
Keyword(s):  
Sugar Beet ◽  
Disease Incidence ◽  
Soil Surface ◽  
Its Region ◽  
Molecular Characteristics ◽  
Damping Off ◽  
First Report ◽  
Binucleate Rhizoctonia ◽  
Hyphal Diameter ◽  
Wheat Seeds

Sugar beet (Beta vulgaris L.) is grown worldwide and produces one-third of the world's sugar supply. Sugar beet seedling Rhizoctonia damping-off is an important disease mainly caused by Rhizoctonia solani AG-2, AG-4, and AG-5 (2). In 2010, diseased sugar beet seedlings with about 20% incidence affected by damping-off, which showed dark brown lesions on the stems just below the soil surface and portions of the roots, were collected from nurseries in three locations in Heilongjiang province, northeast China. Root fragments taken from the margins of healthy tissues and lesions on roots were surface disinfected with 0.5% sodium hypochlorite for 2 min, rinsed with sterile water, then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark. Three (designed HLJ-RAA1, HLJ-RAB1, HLJ-RAB2) of nine Rhizoctonia isolates were obtained from diseased tissues and preliminarily identified as binucleate Rhizoctonia (BNR) anamorph (teleomorph Ceratobasidium Rogers) species-like. Fungal colonies were white with large amounts of floccose, aerial hyphae. Hyphal cells were determined to be binucleate when stained with 4′-6-diamidino-2-phenylindole (DAPI) (1). No sclerotia were produced after 14 days on PDA. Average hyphal diameter of the three isolates were 4.2, 4.3, and 4.8 μm, respectively. Further, the internal transcribed spacer (ITS) region of rDNA was amplified from the genomic DNA extracted from hyphae by bead beating in 2% CTAB solution using stainless steel beads with primers ITS1 and ITS4. The ITS sequences (GenBank Accession Nos. JX073668, JX073669, and JX073670) were over 99% identical to those of more than 50 Ceratobasidium sp. AG-A isolates (e.g., GenBank Accession No. JQ688054.1; strain HY-15). Therefore, based on morphological and molecular characteristics, these isolates were identified to be BNR AG-A. To determine the pathogenicity of the isolates, sugar beet (cv. HI0305) seedlings were inoculated with wheat seeds colonized with each of the isolated Rhizoctonia strains (one seed per seedling), and grew in pots under greenhouse conditions (3). After 3 weeks, some inoculated plants showed damping-off as observed in the nurseries, whereas noninoculated control plants (sterile wheat seeds only) remained healthy. Disease incidence from the trials averaged 53.3%, 70%, and 53.3% for the isolates HLJ-RAA1, HLJ-RAB1, and HLJ-RAB2, respectively. The three BNR cultures of the pathogens were consistently reisolated from symptomatic roots, and their identities confirmed by morphological and molecular characteristics as described above, fulfilling Koch's postulates. BNR AG-A was previously reported to be pathogenic to soybean, pea, snap bean, and pak choy in China (4). However, to our knowledge, this is the first report of BNR AG-A causing sugar beet seedling damping-off in China. Sugar beet is often grown in crop rotation with soya bean and such a rotation could increase the risk of soilborne infection to either crop by BNR AG-A. References: (1) W. C. Kronland and M. E. Stanghellini. Phytopathology 78:820, 1988. (2) E. O'Sullivan and J. A. Kavanagh. Plant Pathol. 40:128, 1991. (3) C. E. Windels and D. J. Nabben. Phytopathology 79:83, 1989. (4) G. H. Yang et al. J. Phytopathol. 153:333, 2005.

scholarly journals Yield losses and control by sedaxane and fludioxonil of soil-borne Rhizoctonia, Microdochium and Fusarium species in winter wheat

Plant Disease ◽  
2021 ◽  
Author(s):  
Matthew Brown ◽  
Dasuni Jayaweera ◽  
Annabel Hunt ◽  
James Warwick Woodhall ◽  
Rumiana V Ray
Keyword(s):  
Seed Treatment ◽  
Field Experiments ◽  
Fusarium Species ◽  
Severe Disease ◽  
Foot Rot ◽  
Damping Off ◽  
Stem Base ◽  
Soil Borne Pathogens ◽  
Sharp Eyespot ◽  
Brown Foot Rot

Soil-borne Rhizoctonia, Microdochium and Fusarium species are major causal agents of seedling and stem-base diseases in wheat and currently seed treatments are considered the most effective solution for their control. Rhizoctonia solani anastomosis groups (AGs) 2-1 and 5, R. cerealis, Microdochium and Fusarium spp. were used in series of field experiments to determine their capability to cause soil-borne and stem-base disease and to quantify their comparative losses in establishment and yield of wheat. The effectiveness and the response to seed treatment formulated of 10 g sedaxane and 5 g fludioxonil 100 kg-1 against these soil-borne pathogens were also determined. Our results showed that damping off caused by soil-borne R. cerealis was associated with significant reductions in emergence and establishment resulting in stunted growth and low plant numbers. The pathogen also caused sharp eyespot associated with reductions in ear partitioning index. R. solani AG 2-1 or AG 5 were weakly pathogenic and failed to cause significant damping off, root rot or stem-base disease in wheat. Fusarium graminearum and F. culmorum applied as soil-borne inoculum failed to cause severe disease. Microdochium spp. caused brown foot rot disease and soil-borne M. nivale reduced wheat emergence. Application of sedaxane and fludioxonil increased plant emergence and reduced damping off, early stem-base disease and brown foot rot thus providing protection against multiple soil-borne pathogens. R. cerealis reduced thousand grain weight by 3.6% whilst seed treatment of fludioxonil and sedaxane against soil-borne R. cerealis or M. nivale resulted in 4% yield increase.

scholarly journals Identity and prevalence of wheat damping-off fungal pathogens in different fields of Basrah and Maysan provinces

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Mohammed Hamza Abass ◽  
Qusai Hattab Madhi ◽  
Abdulnabi Abdul Ameer Matrood
Keyword(s):  
Fusarium Solani ◽  
Seed Treatment ◽  
Fungal Pathogens ◽  
Laboratory Experiments ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Cereal Crops ◽  
Damping Off ◽  
Fungal Isolation ◽  
The World

Abstract Background Wheat is the most consumed cereal crops in the world infected by several pathogens and pests causing significant losses. The most threatening pathogens are fungi which cause serious diseases on roots, leaves and heads as one of the most threatening pathogens in specific wheat-growing countries. This study aimed to identify and evaluate the prevalence of damping-off fungal pathogens in different wheat fields at Basra and Maysan provinces. Results Disease incidence determination and fungal isolation were carried out from two sites at Basra province (Al-Qurna and Al-Madinah) and three sites at Maysan province (Al-Amarah, Kumit, Ali Al Sharqi and Ali Al Gharbi). Al-Qurna fields had the highest disease incidence (32%), while Ali-Alsharqi fields had the lowest one (11%). Fourteen fungal genera were identified. Rhizoctonia solani had the highest appearance (21.6) and frequency (20.20%) percentages followed by Fusarium solani (16.11,14.01) percentages and Macrophomina phaseolina (12.2,11.1) percentages. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Seed treatment with R. solani (Rs1 isolate) showed significant decrease in germination (56.6%) compared to F. solani and M. phaseolina treatments. Conclusions These results revealed the prevalence of wheat damping-off disease in all examined fields at both Basra and Maysan province; the highest disease incidence was seen in Basra wheat fields (Al-Qurna fields); the identification of fungal pathogens showed that the most isolated fungus was R. solani followed by F. solani and M. phaseolina. Laboratory experiments showed the pathogenicity of isolated fungi which varied according to the isolate type.

scholarly journals Seed Rot and Damping-off of Alfalfa in Minnesota Caused by Pythium and Fusarium Species

Plant Disease ◽  
2017 ◽  
Vol 101 (11) ◽  
pp. 1860-1867 ◽  
Author(s):  
Laurine E. Berg ◽  
Susan S. Miller ◽  
Melinda R. Dornbusch ◽  
Deborah A. Samac
Keyword(s):  
Root Rot ◽  
Seed Treatment ◽  
Production Systems ◽  
Fusarium Species ◽  
Broad Host Range ◽  
Damping Off ◽  
Pythium Sylvaticum ◽  
Seed Rot ◽  
New Strategies

Globally, 15 Pythium species have been found to cause damping-off and seed rot of alfalfa, although surveys of species causing disease on alfalfa in the midwestern United States are lacking. Pathogens were isolated by a seedling baiting technique from soil samples of five alfalfa fields in Minnesota with high levels of damping-off. Of the 149 organisms isolated, 93 (62%) were identified as Pythium spp. and 43 (29%) were identified as Fusarium species. Pythium sylvaticum, P. irregulare, and P. ultimum var. ultimum were aggressive pathogens on germinating alfalfa seedlings. Strains of seven Pythium spp. pathogenic on soybean and corn were also pathogenic on alfalfa. The majority of the Fusarium isolates were identified as F. solani and F. oxysporum with a low number of F. redolens and F. incarnatum-equiseti. The F. oxysporum and F. incarnatum-equiseti strains were the most aggressive in causing seed and root rot. Pythium strains were sensitive to Apron XL (mefenoxam) and pyraclostrobin in vitro but efficacy varied when the fungicides were applied as a seed treatment. Seed treatments with Apron XL were more effective than treatments with Stamina against Pythium. The presence of aggressive, broad-host-range pathogens causing seed rot and damping-off suggests that new strategies are needed for managing this disease in alfalfa production systems.

First Report of Globisporangium ultimum Causing Constriction on Hypocotyl of Beta vulgaris in North Dakota, USA

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Parvin MS ◽  
◽  
Haque ME ◽  
Keyword(s):  
Sugar Beet ◽  
North Dakota ◽  
Beta Vulgaris ◽  
Pinus Halepensis ◽  
Disease Incidence ◽  
Post Inoculation ◽  
Damping Off ◽  
First Report ◽  
Wide Range ◽  
Genus 2

Sugar beet (Beta vulgaris) sowing to post-harvest is continuously encountered with wide range of soil-borne pathogens including Rhizoctonia, Fusarium, Aphanomyces, Rhizopus, Pythium, Talaromyces, Clonostachys, and Geotrichum. These evident to cause substantial qualitative and quantitative losses. In May/2019, dark brown to black irregular water-soaked lesions were observed near the soil-line (constriction of hypocotyl) on sugar beet seedlings in Prosper (46.9630° N, 97.0198° W), North Dakota (Figure 1). Approximately 2-5% of disease incidence was recorded. Small pieces (10 mm²) of symptomatic root tissues were cut from the margins between infected and healthy tissue, and disinfected with 10% sodium hypochlorite for 1 min, rinsed three times with autoclaved water, and then placed on Corn Meal Agar (CMA) amended with pimaricin-vancomycin- Pentachloronitrobenzene (PCNB) [1] for incubation at 20°C in the dark for 5 days. Subsequently, single hyphal tips were transferred to Water Ager (WA) (Figure 2). In total, 8 isolates were developed from diseased beets. Isolates were developed light fungal biomass on WA in 14 days. Microscopically, hyphal swelling and globular or lemon shaped sporangia were present (Figure 3). Based on macroscopic and microscopic characteristics, the fungus was speculated to be Oomycetes genus [2]. Determining the species, genomic DNAs of 8-isolates were used for Polymerase Chain Reaction (PCR) using ITS- 6 and ITS-7 primer. PCR amplicons were cleaned with E.Z.N.A ®Cycle Pure Kit, OMEGA, and 8 samples were sent for Sanger sequencing to GenScript (Piscataway, NJ) [3]. The sequences were identical, and standard nucleotide blast search showed 99% sequence identity to Globisporangium ultimum (Genbank accessions: MK794771.1). The nucleotide sequence was deposited in Genbank (MN086365.1). Phyto-pathogenicity testing was performed with 2-week old sugar beet susceptible cultivar which was inoculated with a 2-week old WA culture (5 mm² mycelial cut). This plug/mycelial cut was placed at a 1/2-inch depth close to seedlings in each plastic pot (27 x 13 x 13 cm, T.O. Plastics, Inc.; Clearwater, MN, USA) which was filled with vermiculite and perlite mixer (PRO-MIX FLX) amended with osmocote (N-P-K:15-9-12) fertilizer (Scotts Company; Marysville, OH). The pots were arranged in completely randomized design. The study was done twice with four replicates and 10 plants per replicate. One week of post-inoculation, 40% of the inoculated plants developed similar damping-off symptoms as discussed above (Figure 4), whereas mock-inoculated plants were healthy. Pathogen re-isolated from the infected hypocotyl tissue and was further confirmed morphologically and molecularly, fulfilled Koch’s postulates. Globisporangium species complex were previously reported to cause damping-off on aleppo pine (Pinus halepensis Mill) in Australia, Africa, Mediterranean, rootcrown rot of pepper (Capsicum annuum) in Turkey and alfalfa [4- 7]. To our best knowledge, this is the first report of Globisporangium ultimum causing constriction on hypocotyl of sugar beet seedlings in North Dakota, USA.

Sign in / Sign up

Export Citation Format

Share Document