Efficacy of Typhula phacorrhiza as a biocontrol agent of grey snow mould of creeping bentgrass

1998 ◽  
Vol 76 (7) ◽  
pp. 1276-1281 ◽  
Author(s):  
C Wu ◽  
T Hsiang ◽  
L Yang ◽  
L X Liu
Keyword(s):  
Field Tests ◽  
Field Performance ◽  
Creeping Bentgrass ◽  
Disease Suppression ◽  
Significant Control ◽  
Turfgrass Disease ◽  
Snow Mould ◽  
Typhula Incarnata ◽  
Positive Correlations

Isolates of the fungus Typhula phacorrhiza Fries (TP) were evaluated in field tests over a 3-year period for suppression of grey snow mould caused by Typhula ishikariensis Imai (Tish) and Typhula incarnata Lasch ex Fr. (Tinc). Isolates of TP were collected across southern Ontario in the spring of 1994. In December 1994, 46 of these isolates, which had been cultured on mixed grains, were applied to creeping bent grass (Agrostis stolonifera L.) at a rate of 200 g/m2 (4 × 105 colony forming units (cfu)/m2) with inoculum of Tish or Tinc at 10 g/m2 (2 × 104 cfu/m2). In December 1995, 30 selected TP isolates were inoculated onto a new set of plots along with grey snow mould fungi. In November 1996, 22 of these isolates were re-inoculated onto the 1995 plots. All plots were rated for injury after snowmelt, 1995-1997. Isolates of TP varied significantly in their ability to suppress disease. No strong correlations were found between in vitro growth characteristics and field performance; however, significant positive correlations were found between the disease suppression trials for the 3 years, with several isolates showing statistically significant control of grey snow mould equal to a fungicide treatment.Key words: biocontrol, turfgrass disease, fungi.

scholarly journals Control of Dollar Spot of Creeping Bentgrass Caused by an Isolate of Sclerotinia homoeocarpa Resistant to Benzimidazole and Demethylation-Inhibitor Fungicides

Plant Disease ◽  
1997 ◽  
Vol 81 (11) ◽  
pp. 1259-1263 ◽  
Author(s):  
L. L. Burpee
Keyword(s):  
Incubation Period ◽  
Field Tests ◽  
Creeping Bentgrass ◽  
Disease Suppression ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Fungicide Sensitivity ◽  
Thiophanate Methyl ◽  
Demethylation Inhibitor

The effects of fungicides were studied on two isolates of Sclerotinia homoeocarpa that differed in fungicide sensitivity. Concentrations of benzimidazole (benomyl and thiophanate-methyl), demethylation inhibitor (fenarimol, propiconazole, and triadimefon), and nitrile (chlorothalonil) fungicides required to inhibit mycelial growth in vitro by 50 and 90% (effective concentration; EC50,90) were significantly greater for isolate S088 than for isolate S084. No differences were observed in the EC50,90 values of a pyridylaniline (fluazinam) or dicarboximide (iprodione) fungicide. In field tests conducted on creeping bentgrass, S088 had a significantly shorter incubation period than S084 in plots treated with propiconazole applied at 0.2 or 0.8 kg a.i. ha-1 in 1994 or 0.4 kg a.i. ha-1 in 1995, thiophanate-methyl applied at 1.5 or 3.0 kg a.i. ha-1 in 1994 and 1995, or a tank-mix of propiconazole and iprodione applied at 1.6 + 0.8 kg a.i. ha-1 in 1994. No differences in incubation periods occurred in plots treated with chlorothalonil or iprodione in either year, or with fluazinam in 1995 and 1996. Fewer days were required to reach 5% disease severity in turf inoculated with isolate S088, compared to isolate S084, in plots treated with propiconazole, thiophanate-methyl, or certain tank-mixes containing propiconazole, in 1994 and 1995. Several treatments, including propiconazole, thiophanate-methyl, and fluazinam, resulted in suppression of disease caused by isolate S084 to less than 5% severity for more than 21 days, while only fluazinam applied at 1.6 or 3.2 kg a.i. ha-1 provided more than 21 days of disease suppression in turf inoculated with either of the isolates tested. Slope coefficients from linear regressions between incubation period or days to 5% disease and concentrations of fungicide applied in 1996 were significantly different for isolate S084 compared to isolate S088 in plots treated with propiconazole, but not in plots treated with fluazinam.

Mycelial growth, sclerotial production and carbon utilization of three Typhula species

1999 ◽  
Vol 77 (2) ◽  
pp. 312-317
Author(s):  
C Wu ◽  
T Hsiang
Keyword(s):  
Radial Growth ◽  
Mycelial Growth ◽  
Biocontrol Agent ◽  
Carbon Sources ◽  
Carbon Utilization ◽  
Turfgrass Disease ◽  
Snow Mould ◽  
Typhula Incarnata ◽  
And Storage ◽  
Temperature Optima

The mycelial growth, sclerotial production, and carbon utilization of the snow mould biocontrol agent Typhula phacorrhiza Fries were compared with the two grey snow mould fungi, Typhula ishikariensis Imai and Typhula incarnata Lasch ex Fries. Variation was observed among the four isolates for each species, but there was greater variation among species. All three species were able to grow at the lowest temperature (0°C), but temperature optima differed with T. ishikariensis lowest and T. phacorrhiza highest. On potato dextrose agar or potato malt agar at 10°C, T. phacorrhiza had greater radial growth than T. ishikariensis but less than T. incarnata. All species could utilize microcrystalline cellulose, bacto-cellulose, and glucose as carbon sources, but radial growth of T. phacorrhiza was significantly greater than T. incarnata and T. ishikariensis on these defined carbon sources tested, except for Indulin-AT, which was inhibitory to T. incarnata and T. phacorrhiza. This greater ability to utilize these structural and storage carbohydrates, combined with mycelial growth and sclerotial production over a wider range of temperatures, may help explain how some isolates of T. phacorrhiza are able to outcompete grey snow mould in field tests.Key words: turfgrass disease, biocontrol, psychrophilic.

scholarly journals Preventive Control of Pythium Root Dysfunction in Creeping Bentgrass Putting Greens and Sensitivity of Pythium volutum to Fungicides

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1275-1280 ◽  
Author(s):  
J. P. Kerns ◽  
M. D. Soika ◽  
L. P. Tredway
Keyword(s):  
Fungicidal Activity ◽  
Creeping Bentgrass ◽  
Disease Suppression ◽  
Preventive Control ◽  
Putting Greens ◽  
In Vitro Sensitivity ◽  
Putting Green ◽  
Field Efficacy

Pythium root dysfunction (PRD), caused by Pythium volutum, has been observed on golf course putting greens established with creeping bentgrass in the southeastern United States since 2002. To evaluate preventative strategies for management of this disease, a 3-year field experiment was conducted in Pinehurst, NC on a ‘G-2’ creeping bentgrass putting green. Fungicide treatments were applied twice in the fall (September and October) and three times in the spring (March, April, and May) in each of the 3 years. Applications of pyraclostrobin provided superior preventative control compared with the other fungicides tested. Azoxystrobin and cyazofamid provided moderate control of PRD in two of three seasons. Experiments were conducted to determine whether the disease suppression provided by pyraclostrobin was due to fungicidal activity or physiological effects on the host. In vitro sensitivity to pyraclostrobin, azoxystrobin, fluoxastrobin, cyazofamid, mefenoxam, propamocarb, and fluopicolide was determined for 11 P. volutum isolates and 1 P. aphanidermatum isolate. Isolates of P. volutum were most sensitive to pyraclostrobin (50% effective concentration [EC50] value = 0.005), cyazofamid (EC50 = 0.004), and fluoxastrobin (EC50= 0.010), followed by azoxystrobin (EC50 = 0.052), and mefenoxam (EC50 = 0.139). P. volutum isolates were not sensitive to fluopicolide or propamocarb. Applications of pyraclostrobin did not increase the foliar growth rate or visual quality of creeping bentgrass in growth-chamber experiments. This work demonstrates that fall and spring applications of pyraclostrobin, azoxystrobin, and cyazofamid suppress the expression of PRD symptoms during summer and that field efficacy is related to the sensitivity of P. volutum to these fungicides.

scholarly journals Toward Fungicidal Management of Laurel Wilt of Avocado

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 977-982 ◽  
Author(s):  
Randy C. Ploetz ◽  
José M. Pérez-Martínez ◽  
Edward A. Evans ◽  
Sharon A. Inch
Keyword(s):  
Radial Growth ◽  
Cost Effective ◽  
Phosphorus Acid ◽  
Persea Americana ◽  
Disease Suppression ◽  
Malt Extract ◽  
Laurel Wilt ◽  
Significant Control ◽  
Raffaelea Lauricola

Laurel wilt threatens commercial and residential production of avocado (Persea americana) in Florida. Laurel wilt on redbay (P. borbonia) was controlled previously with macroinfusions (injections) of Alamo, an injectable formulation of propiconazole. To determine whether Alamo macroinfusion would be cost effective in commercial avocado production, economic analyses were conducted for various macroinfusion scenarios and a standardized production situation in southern Florida. Under prevailing conditions, macroinfusion was not cost effective. In the interest of identifying alternative means to manage the disease, other fungicides and application measures were evaluated. In all, 20 fungicides in 15 chemical groups and 10 fungicide groups were examined in vitro. In vitro inhibition of the radial growth of the pathogen Raffaelea lauricola was determined on fungicide-amended malt extract agar; demethylation inhibitors (DMIs; fenarimol, myclobutanil, propiconazole, prothioconazole, triadimenol, triadimefon, and triticonazole), quinone outside inhibitors (azoxystrobin, pyraclostrobin, and fluoxastrobin), and a quinone inside inhibitor (fluazinam) had the greatest impact on radial growth (the concentration at which growth was reduced by 50% was ≥0.1 μg ml–1). In greenhouse studies, the most inhibitory products in vitro, plus thiabendazole and two products that were not tested in vitro, flutriafol and a potassium salts mixture of phosphorus acid, were tested for disease suppression on artificially inoculated, potted ‘Simmonds,’ a susceptible avocado cultivar. In general, soil drench applications of the above DMIs and thiabendazole but not azoxystrobin, pyraclostrobin, fluazinam, or the phosphorus acid salt provided significant control of disease (P < 0.05). Topical branch or trunk applications of propiconazole, and triadimenol in 2% Pentrabark, a bark-penetrating surfactant, were also effective at lower rates than were used in drench applications. Comparable levels of disease suppression were achieved when propiconazole was applied at 11% of the rates that were used in soil drenches. Although topical fungicide applications in bark-penetrating surfactants would be a less expensive practice than macroinfusion, moving sufficient concentrations of propiconazole or other fungicides into host xylem will be difficult in trees that are larger than the potted plants that were tested in these trials. Ongoing work examines means by which this goal might be met on fruit-bearing trees in the field.

scholarly journals Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches

2011 ◽  
Vol 101 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Brantlee Spakes Richter ◽  
Kelly Ivors ◽  
Wei Shi ◽  
D. M. Benson
Keyword(s):  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Cellulase Activity ◽  
Enzyme Concentration ◽  
Disease Suppression ◽  
In Vitro Assays ◽  
Infested Soil ◽  
Phytophthora Root Rot ◽  
Standard Curve

Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml–1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml–1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml–1. In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml–1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml–1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g–1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g–1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

scholarly journals Alternative Control of Phragmidium rubi-idaei Infecting Two Rubus Species

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1452
Author(s):  
Raluca-Maria Pârlici ◽  
Aurel Maxim ◽  
Stefania Mirela Mang ◽  
Ippolito Camele ◽  
Lucia Mihalescu ◽  
...  
Keyword(s):  
Organic Farming ◽  
Plant Pathogens ◽  
Field Experiments ◽  
Control Sample ◽  
Field Tests ◽  
In Vitro Tests ◽  
Rust Disease ◽  
Conidia Germination ◽  
The Impact

Organic berry plantations have been gaining popularity among farmers during recent years. Even so, farmers experience serious challenges in disease control management, which is a concern in organic farming. Phragmidiumrubi-idaei (DC) P. Karst is the pathogen responsible for blackberry and raspberry rust disease, one of the most present and active diseases in plantations. The antifungal certified products found on the organic farming market offer the opportunity for an efficient control strategy over plant pathogens in fruit shrub plantations. In this study, 5 natural based products—namely Altosan, Mimox, Canelys, Zitron, and Zeolite—were tested for their fungistatic effect over P. rubi-idaei. The experiments were carried out under laboratory conditions, performing observations over the impact of organic products, used at different concentration levels, on rust conidia germination. Moreover, field experiments were conducted in order to evaluate the efficiency of different treatments for rust control on raspberry (‘Polka’, ‘Veten’ and ‘Heritage’) and blackberry (‘Thorn Free’, ‘Chester’ and ‘Loch Ness’) varieties. Data analysis based on ANOVA tests showed significant differences between the tested variants and the control sample at p < 0.001. Furthermore, LSD test confirmed differences between all substances tested (p < 0.005). The natural products Canelys (formulated with cinnamon) and Zytron (based on citrus extract) have proven the highest inhibitory capacity for conidia germination during in vitro tests registering values of 80.42% and 78.34%, respectively. The same high inhibitory rates against rust pathogen were kept also in the field tests using the same two natural-based products mentioned earlier. In addition, outcomes from this study demonstrated that Zeolite is not recommended for raspberry or blackberry rust control.

Thymol and its Derivatives for Management of Phytopathogenic fungi of maize

2021 ◽  
Vol 18 ◽  
Author(s):  
Jyoti Gaba ◽  
Sunita Sharma ◽  
Harleen Kaur ◽  
Pardeep Kaur
Keyword(s):  
Pathogenic Fungi ◽  
Bioactive Compound ◽  
Mannich Bases ◽  
Phytopathogenic Fungi ◽  
Leaf Blight ◽  
Significant Control ◽  
Thymol Derivatives ◽  
Potential Alternative ◽  
Blight Disease

Background: Thymol is a bioactive compound having many pharmacological activities. Objective: The present study was carried out to evaluate the fungi toxic effects of thymol and derivatives against phytopathogenic fungi of maize. Method: Thymol was derivatized to get formylated thymol, Mannich bases, and imine derivatives. All the synthesized thymol derivatives were characterized by their physical and spectral properties. Synthesized thymol derivatives were screened for their in vitro antifungal effects using poisoned food technique against three maize pathogenic fungi namely Fusarium moniliforme, Rhizoctonia solani and Dreschlera maydis. Results: Thymol and formylated thymol showed promising results for control of D. maydis with ED50 values less than standard carbendazim and comparable to standard mancozeb. These two compounds were further evaluated for control of D. maydis causative maydis leaf blight disease on maize plants grown in the field during the Kharif season (June to October) 2018. Conclusion: Thymol exhibited significant control of maydis leaf blight disease of maize and emerged as a potential alternative to synthetic fungicides used in cereal crops.

PSV-5 Relationship between sire conception rate, sperm motility, sperm SERPINA5 relative concentration, and in vitro produced embryos in dairy bulls

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 310-310
Author(s):  
Saulo Menegatti Zoca ◽  
Julie Walker ◽  
Taylor Andrews ◽  
Adalaide C Kline ◽  
Jerica J Rich ◽  
...  
Keyword(s):  
Embryo Development ◽  
Sperm Motility ◽  
Relative Concentration ◽  
Early Embryo ◽  
Conception Rate ◽  
Cleavage Rate ◽  
Blastocyst Rate ◽  
Positive Correlations ◽  
Sire Conception Rate

Abstract Sire conception rate (SCR) is a field measure of fertility among bulls, but it can be influenced by several factors (Sperm transport, sperm-egg binding, early embryo development, etc). The objective of this study was to evaluate the relationship between SCR, sperm motility, SERPINA5 concentrations, and in vitro embryo development. Measurements were performed in 19 bulls with SCR values ranging from -7.7 to 4.45. For each bull, an aliquot of frozen-thawed semen was used for analyses of total (TMOT) and progressive (PROG) motility. Remaining semen was fixed with 2% formaldehyde, and concentration of SERPINA5 was determined by immunolocalization (antibody SERPINA5/Dylight405; PA5-79976-Invitrogen / ab201798-Abcam). Mean fluorescence intensity was determined in ~200 sperm heads/bull. Approximately 149 oocytes/bull were fertilized in vitro for embryo development analysis (cleavage and blastocyst rates). Statistical procedures were performed in SAS (9.4) using the procedures CORR for correlations (SCR, TMOT, PROG, SERPINA5, cleavage and blastocyst) and GLIMMIX for comparison of “field-fertility” (SCR divided in HIGH or LOW) and “field-embryo-fertility” (LOW-SCR sires were divided based on blastocyst rate (HIGH or LOW) resulting in two classifications; LOW-HIGH≥31% and LOW-LOW≤26%, respectively). There were positive correlations (P &lt; 0.05) between cleavage-blastocyst (r=0.50), SERPINA5-cleavage (r=0.48), and TMOT-PROG (r=0.76). Sire SCR was not associated with SERPINA5, TMOT, PROG, cleavage and blastocyst rate (P &gt; 0.52). Among LOW-SCR sires, LOW-LOW sires (-4.83±0.60) tended to have a better SCR score than LOW-HIGH (-6.18±0.42) sires (P = 0.08), but there were no differences (P &gt; 0.43) between LOW-HIGH, LOW-LOW, and HIGH sires for SERPINA5, TMOT, PROG, and cleavage. In conclusion, some LOW SCR sires have good embryo development indicating a different mechanism for their low SCR; however, these differences in SCR could not be explained by TMOT, PROG, SERPINA5, cleavage and blastocyst. There were, however, positive correlations between cleavage-blastocyst rate, and SERPINA5-cleavage rate.

EFFICACY OF RHIZOBACTERIA ON PLANT GROWTH PROMOTION AND DISEASE SUPPRESSION IN VITRO

2012 ◽  
pp. 525-532 ◽  
Author(s):  
S. Velivelli ◽  
E. O'Herlihy ◽  
B. Janczura ◽  
B. Doyle Prestwich ◽  
J. Ghyselinck ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Disease Suppression

scholarly journals The Association Between In Vitro Propiconazole Sensitivity and Field Efficacy of Five New England Sclerotinia homoeocarpa Populations

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 552-561 ◽  
Author(s):  
James T. Popko ◽  
Chang-Ho Ok ◽  
Katie Campbell-Nelson ◽  
Geunhwa Jung
Keyword(s):  
New England ◽  
Field Resistance ◽  
Golf Club ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Mycelium Growth ◽  
Turfgrass Disease ◽  
Country Club ◽  
Field Efficacy

Dollar spot (Sclerotinia homoeocarpa) is a major turfgrass disease requiring fungicide application to maintain acceptable conditions for golf. A 2-year field experiment was conducted to determine the association between field efficacy of propiconazole and in vitro fungicide sensitivity of isolates from five S. homoeocarpa populations. Four golf courses with prior propiconazole exposure (Hartford Golf Club, Hickory Ridge Country Club, Shuttle Meadow Country Club, and Wintonbury Hills Golf Club), and a baseline site with no prior propiconazole exposure (Joseph Troll Turf Research Facility) were chosen as field sites. Experimental plots at each site received the following treatments at 21-day intervals: untreated, propiconazole (0.44, 0.88, 1.32, and 1.76 kg a.i. ha–1), and chlorothalonil (8.18 kg a.i. ha–1). S. homoeocarpa isolates were sampled at three time points during 2009 and 2010: initial (directly before fungicide treatment), 7 days after treatment (DAT), and 21 days after the last treatment. Isolates sampled from dollar spot infection centers at 7 DAT (2009 and 2010) were considered to exhibit “practical field resistance”. In parallel, S. homoeocarpa isolates from each site were assayed for in vitro sensitivity to propiconazole by determining relative mycelium growth percentages (RMG%) on potato dextrose agar amended with propiconazole at a discriminatory concentration of 0.1 μg a.i. ml–1. S. homoeocarpa isolates from the four exposed populations displayed significantly higher RMG% values than the baseline population. In general, field efficacy at all propiconazole rates tested was lower at the four locations with prior propiconazole exposure when compared with the baseline population. Increased RMG% values on the propiconazole discriminatory concentration 0.1 μg a.i. ml–1 were associated with decreased relative control values for all propiconazole rates in 2009 and 2010. Results suggest RMG values above 50% at the propiconazole discriminatory concentration of 0.1 μg a.i. ml–1 may be a suitable threshold for detection of S. homoeocarpa isolates that cause practical DMI field resistance.

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