Damping-off of sugar beet in Finland: III Effect of temperature and disease forecasting

1984 ◽  
Vol 56 (4) ◽  
pp. 283-290
Author(s):  
Mauritz Vestberg
Keyword(s):  
Sugar Beet ◽  
Disease Incidence ◽  
Peat Soil ◽  
Fine Sand ◽  
Effect Of Temperature ◽  
Strong Increase ◽  
Inoculum Potential ◽  
Damping Off ◽  
Emergence Period ◽  
High Level

The effect of temperature on the severity of damping-off of sugar beet was studied under controlled conditions. The disease incidence increased with increasing temperature. When the time up to emergence in a finesand soil was characterized by low temperatures (8°C night, 15°C day), a period of 14—21 days immediately after emergence caused a strong increase in disease incidence. In peat soil, even 7 days was enough to initiate such an increase. In neither of the soils used did three days of high post-emergence temperature cause any marked disease increase. When the pre-emergence period was characterized by high temperatures (15°C night, 25°C day) the disease was at a high level and in the very fine sand soil could not be lowered by lower temperatures. In the peat soil, however, a constant, low postemergence temperature significantly inhibited the development of the disease. The possibilities of damping-off forecasting by comparing the disease incidence in pot experiments to damping-off in the field seemed rather limited. When the temperature is taken into account, a negative prognosis may be possible. The basis of such a prognosis is the determination of the inoculum potential of the soil.

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 Effects of inoculum potential on screening for resistance to Plasmodiophora brassicae in greenhouse trials

2013 ◽  
Vol 41 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Józef Robak ◽  
R. L. Gabrielson
Keyword(s):  
Growth Medium ◽  
Chinese Cabbage ◽  
Plasmodiophora Brassicae ◽  
Disease Incidence ◽  
Frozen Storage ◽  
Inoculum Potential ◽  
Screening For Resistance ◽  
Petri Dishes ◽  
High Level ◽  
Inoculum Storage

Several factors, including growth medium, inoculum density, and inoculum storage affected the reaction of resistant and susceptible Brassicas to <i>Plasmodiophora brassicae</i> in the greenhouse. A high level of disease was achieved using Peat-litte mix R and a commercial greenhouse mix. There was litte difference in disease incidence when spore suspensions were pipeted into planting holes or when seedlings were dipped into spore suspensions. Seedlings transplanted from sand or Petri dishes gave higher levels of disease than direct seeding. Two-year frozen storage of clubs reduced the inoculum potential to a level unable to define resistance. Inoculum levels of 10<sup>3-7</sup> spores per ml from fresh clubs, or 10<sup>5-7</sup> spores per ml from clubs frozen for 2 or 4 years, produced 90% club incidence of susceptible cauliflower and Chinese cabbage, A concentration of only 10<sup>6-8</sup> spores per ml from fresh clubs was required for maximum disease expression in a cauliflower line partially resistant to clubroot.

scholarly journals Preliminary experiments into the use of Streptomyces spp. isolated from peat in the biological control of soil and seed-borne diseases in peat culture 

1982 ◽  
Vol 54 (5) ◽  
pp. 357-369 ◽  
Author(s):  
Risto Tahvonen
Keyword(s):  
Biological Control ◽  
Sugar Beet ◽  
Fusarium Culmorum ◽  
Fine Sand ◽  
Alternaria Brassicicola ◽  
Foot Rot ◽  
Damping Off ◽  
Sand Soil ◽  
Seeding Layer ◽  
Streptomyces Spp

Streptomyces spp. isolates obtained from peat effectively inhibited the growth of Alternaria brassicicola Wiltshire, Fusarium culmorum (W. G. Smith) Sacc., F. sulphureum Schlechtendahl, Pythium debaryanum auct. non Hesse and Rhizoctonia solani Kühn on PDA medium, but Streptomyces spp. isolates from fine sand soil were not effective against F. culmorum compared to the strains isolated from peat. Treatment of cauliflower seeds with Streptomyces spp. isolated from peat effectively controlled damping-off caused by A. brassicicola and R. solani when the seedlings were grown on either disinfected or fresh peat. Spraying the seeding layer of the peat substrate with a suspension of Streptomyces reduced the mortality of barley sprouts and foot rot caused by F. culmorum, and damping-off on sugar beet caused by P. debaryanum.

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.

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.

Damping-off of sugar beet in Finland: II. Disease control 

1983 ◽  
Vol 55 (5) ◽  
pp. 431-450
Author(s):  
Mauritz Vestberg ◽  
Risto Tahvonen ◽  
Kyösti Raininko
Keyword(s):  
Sugar Beet ◽  
Disease Control ◽  
Field Experiments ◽  
Damping Off ◽  
Good Protection ◽  
Great Damage

In pot and field experiments carried out in 1979-1981, the systemic funqicide hymexazol prevented satisfactorily soil borne damping-off of sugar beet caused mainly by the fungus Pythium debaryanum auct. non Hesse. The results with the combination hymexazol + thiram were still better. This treatment gave very good protection against the disease up to about two to three weeks after emergence, increased the yield on the average by 5-10 % and produced considerably thicker and denser stands. Thereafter a large number of beets may have become infected, but no great damage was caused as only few died. Band spraying at emergence using hymexazol with a large amount of water as well as spraying into the seed furrow prevented the outbreak of the disease almost completely. Liming had little effect on damping-off.

scholarly journals Penicillium pinophilum has the Potential to Reduce Damping-off Caused by Rhizoctonia solani in Sugar Beet

Sugar Tech ◽  
2021 ◽  
Author(s):  
Md Ehsanul Haque ◽  
Dilip K. Lakshman ◽  
Aiming Qi ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Damping Off ◽  
Penicillium Pinophilum

scholarly journals Sensitivity of Rhizoctonia solani AG-2-2 from Sugar Beet to Fungicides

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Sahar Arabiat ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
The United States ◽  
Damping Off ◽  
Growth Assay ◽  
The Mean ◽  
Crown And Root Rot ◽  
Mean Concentration

Rhizoctonia damping-off and crown and root rot caused by Rhizoctonia solani are major diseases of sugar beet (Beta vulgaris L.) worldwide, and growers in the United States rely on fungicides for disease management. Sensitivity of R. solani to fungicides was evaluated in vitro using a mycelial radial growth assay and by evaluating disease severity on R. solani AG 2-2 inoculated plants treated with fungicides in the greenhouse. The mean concentration that caused 50% mycelial growth inhibition (EC50) values for baseline isolates (collected before the fungicides were registered for sugar beet) were 49.7, 97.1, 0.3, 0.2, and 0.9 μg ml−1 and for nonbaseline isolates (collected after registration and use of fungicides) were 296.1, 341.7, 0.9, 0.2, and 0.6 μg ml−1 for azoxystrobin, trifloxystrobin, pyraclostrobin, penthiopyrad, and prothioconazole, respectively. The mean EC50 values of azoxystrobin, trifloxystrobin, and pyraclostrobin significantly increased in the nonbaseline isolates compared with baseline isolates, with a resistant factor of 6.0, 3.5, and 3.0, respectively. Frequency of isolates with EC50 values >10 μg ml−1 for azoxystrobin and trifloxystrobin increased from 25% in baseline isolates to 80% in nonbaseline isolates. Although sensitivity of nonbaseline isolates of R. solani to quinone outside inhibitors decreased, these fungicides at labeled rates were still effective at controlling the pathogen under greenhouse conditions.

scholarly journals First Report of Damping-Off Caused by Rhizoctonia solani AG-4 on Mediterranean Fan Palm in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 125-125 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
I. Castello ◽  
V. Guarnaccia ◽  
A. Vitale
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Fluorescent Light ◽  
Damping Off ◽  
Centraalbureau Voor ◽  
First Report ◽  
Stem Lesions

Mediterranean fan palm (Chamaerops humilis L.), one of just two autochthonous European palms, is native to the western Mediterranean Region in southwestern Europe and northwestern Africa. It can be found growing wild in the Mediterranean area. In Europe, this species is very popular as an ornamental plant. In March 2009, a widespread damping-off was observed in a stock of approximately 30,000 potted 1-month-old plants of C. humilis cv. Vulcano in a nursery in eastern Sicily. Disease incidence was approximately 20%. Disease symptoms consisted of lesions at the seedling shoot (plumule). Stem lesions were initially orange, turned brown, and followed by death of the entire plumule or eophyll. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from lesions when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates with tester strains AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11 on 2% water agar in petri plates (3). Anastomosis was observed only with tester isolates of AG-4, giving both C2 and C3 reactions (2). One representative isolate obtained from symptomatic tissues was deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (CBS No. 125095). Pathogenicity tests were performed on container-grown, healthy, 1-month-old seedlings. Twenty plants of C. humilis cv. Vulcano were inoculated near the base of the stem with two 1-cm2 PDA plugs from 5-day-old mycelial cultures. The same number of plants served as uninoculated controls. Plants were incubated in a growth chamber and maintained at 25°C and 95% relative humidity on a 12-h fluorescent light/dark regimen. Symptoms identical to those observed in the nursery appeared 5 days after inoculation and all plants died within 20 days. No disease was observed on control plants. A fungus identical in culture morphology to R. solani AG-4 was consistently reisolated from symptomatic tissues, confirming its pathogenicity. To our knowledge, this is the first report in the world of R. solani causing damping-off on Mediterranean fan palm. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (3) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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