scholarly journals Improving Fungicide-Based Management of Ray Blight Disease in Tasmanian Pyrethrum Fields

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 887-895 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Frank S. Hay ◽  
Tim Groom ◽  
Calum R. Wilson
Keyword(s):  
Dry Weight ◽  
Field Trials ◽  
Early Spring ◽  
Primary Objective ◽  
Canopy Reflectance ◽  
Resistance Development ◽  
Ray Blight ◽  
The Difference ◽  
Blight Disease

Ray blight disease, caused by Phoma ligulicola var. inoxydablis, is a serious threat to the Tasmanian pyrethrum industry. The management of this disease relies upon the strategic application of fungicides in early spring. A range of fungicides were assessed for their efficacy in controlling ray blight disease in Tasmanian pyrethrum fields, and the primary objective of this study was to increase fungicide options available to growers in different resistance groups. Fungicides were assessed under in vitro conditions, within five replicated-plot field trials over three seasons (2004 to 2006) and in single-plot trials over eight fields in 2005. In each of the field trials, regular assessments of disease intensity (defoliation severity and the incidence of stems with ray blight), stem height, and the number of flowers produced on each stem were made using stems as the primary sampling unit. Canopy reflectance at 830 nm and the Difference Vegetative Index, measured using a handheld multispectral radiometer, also were used to compare fungicide effects on green leaf area. The effect of fungicides on the dry weight of flowers, pyrethrin content within the flowers, flower maturity, and pyrethrin yield were determined. Under in vitro conditions, boscalid reduced both conidial germination and mycelial growth at concentrations of at least 0.16 μg/ml. In field trials 1 and 2 (in 2004), the premixed formulation of pyraclostrobin + boscalid (Pristine) increased pyrethrin yield by an average of 79% compared with nontreated plots over the two locations. Furthermore, in single-plot trials, pyraclostrobin + boscalid increased pyrethrin yield by 134 and 60% compared with the industry-recommended protocol (single application of azoxystrobin at 150 g a.i./ha [Amistar WG] and two additional applications of a tank mixture of difenoconazole at 125 g a.i./ha [Score] and chlorothalonil at 1,008 liters a.i./ha [Bravo 720] at 14- to 21-day intervals) and nontreated plots, respectively. In field trials 3 (in 2005) and 4 and 5 (in 2006), similar yield benefits also were produced by applying pyraclostrobin (Cabrio SC) or boscalid (Filan) alone or in combination with chlorothalonil (Bravo 720) at 1.4 liters of product per hectare, regardless of the rates of pyraclostrobin (250 and 125 g a.i./ha) and boscalid (500 and 250 g a.i./ha) used. These data were used to recommend the incorporation of boscalid to improve the fungicide-based management of ray blight disease. This decreases the number of applications of both strobilurin and triazole fungicides which have been used extensively for the management of ray blight and other diseases in Tasmanian pyrethrum fields and are prone to fungicide resistance development.

scholarly journals Development of a Fungicide-Based Management Strategy for Foliar Disease Caused by Phoma ligulicola in Tasmanian Pyrethrum Fields

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1114-1120 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Frank S. Hay ◽  
Calum R. Wilson ◽  
Tim Groom
Keyword(s):  
Mycelial Growth ◽  
Management Strategy ◽  
Cost Effective ◽  
Field Trials ◽  
Early Spring ◽  
Effective Management ◽  
Ray Blight ◽  
Low Concentrations ◽  
Demethylation Inhibitor

The efficacy of a range of fungicides were assessed under in vitro conditions in four field trials over three seasons for the management of ray blight of pyrethrum, caused by the fungus Phoma ligulicola in Tasmania. Fungicides belonging to the demethylation inhibitor group, including prochloraz, tebuconazole, difenoconazole, and cyproconazole, produced the most significant reduction in mycelial growth in vitro compared with unamended controls. Significant reductions in germination of conidia resulted from low concentrations of azoxystrobin. In the field, azox-ystrobin (as Amistar) at a rate of 300 g of product/ha significantly decreased disease intensity and increased pyrethrin yield (kg/ha) in all seasons. Applications of either azoxystrobin or difenoconazole (as Score) at a rate of 250 ml of product/ha in early spring were the most effective, whereas no significant benefit was demonstrated from applications in autumn. Over all seasons, azoxystrobin applications resulted in double the weight of flowers produced compared with nontreated areas, whereas increases in pyrethrin content within the flowers were season and location specific. Application of azoxystrobin and chlorothalonil (as Bravo 720) at a rate of 1.4 liters of product/ha resulted in a 45 to 48% increase in flowers, reduced defoliation, and increased stem diameter. The weight of individual flowers and flower maturity was not significantly affected by fungicide application. These data provide the basis for cost-effective management of this disease.

Prevention and Detection of Fungicide Resistance Development in Rhizoctonia zeae from Soybean and Corn in Nebraska

2021 ◽  
Author(s):  
Nikita Gambhir ◽  
Srikanth Kodati ◽  
Matthew Huff ◽  
Flávio Silva ◽  
Olutoyosi Ajayi-Oyetunde ◽  
...  
Keyword(s):  
Fungicide Resistance ◽  
Resistance Management ◽  
Dry Weight ◽  
Geographic Region ◽  
Population Characteristics ◽  
Current Status ◽  
In Planta ◽  
Resistance Development ◽  
Rhizoctonia Zeae

The goal of this research was to advance the foundational knowledge required to quantify and mitigate fungicide resistance in Rhizoctonia zeae, the seedling disease pathogen of soybean and corn. In vitro sensitivity to azoxystrobin, fludioxonil, sedaxane, and/or prothioconazole was determined for 91 R. zeae isolates obtained mostly from soybean and corn fields in Nebraska. Isolates were sensitive to fludioxonil, sedaxane, and prothioconazole (EC50 < 3 µg/ml) and had a positively skewed EC50 distribution. Isolates were not sensitive to azoxystrobin in vitro (EC50 > 100 µg/ml) or in planta. Application of azoxystrobin did not significantly decrease disease severity or improve total dry weight of the soybean plants (P > 0.05). The risk of resistance development in R. zeae was estimated by characterizing its population structure. Eighty-one R. zeae isolates were genotyped using six microsatellite markers. Results showed that the population has a mixed mode of reproduction and is structured according to geographic region, suggesting limited dispersal. These population characteristics suggest that R. zeae has an intermediate risk of resistance development. Overall, this research established the current status of fungicide sensitivity in R. zeae in Nebraska and estimated its risk of resistance development, which can inform fungicide resistance management for R. zeae.

scholarly journals Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

2019 ◽  
Author(s):  
Lirong Chen ◽  
Yuqiu Guo ◽  
Xiaoyue Li ◽  
Kuijie Gong ◽  
Kaichang Liu
Keyword(s):  
Radical Scavenging ◽  
Dry Weight ◽  
Sodium Cholate ◽  
Free Form ◽  
Functional Activities ◽  
Free Phenolics ◽  
The Difference ◽  
Different Color ◽  
Waxy Corn

Abstract The polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 μg/g DW (dry weight), which was slightly higher (p >0.05) than that of the total bound form (6276.65 μg/g DW). The total free flavonoid content was 5850.09 μg/g DW, which was higher (p < 0.05) than that of the total bound form (4874.51μg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86-100% and 70-78% of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100% of the ferric reducing capacity. The free phenolics in fresh waxy corn showed significantly better (p< 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed significantly better (p < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

Phytotoxicity of 2,4-D and 2,4-Dichlorophenol to Red Clover (Trifolium pratense)

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry
Keyword(s):  
Trifolium Pratense ◽  
Callus Tissue ◽  
Red Clover ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
The Difference ◽  
Plant Level

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.

Glucosinolate Production by Five Field-GrownBrassica napusCultivars Used as Green Manures

1998 ◽  
Vol 12 (4) ◽  
pp. 712-718 ◽  
Author(s):  
Charlotte V. Eberlein ◽  
Matthew J. Morra ◽  
Mary J. Guttieri ◽  
Paul D. Brown ◽  
Jack Brown
Keyword(s):  
Brassica Napus ◽  
Biomass Production ◽  
Green Manure ◽  
Cropping Systems ◽  
Dry Weight ◽  
Field Trials ◽  
Early Spring ◽  
Green Manures ◽  
Winter Rape ◽  
Glucosinolate Concentration

Winter rape (Brassica napusL.) green manures have shown potential for erosion control and suppression of weeds and other pests in potato cropping systems. However, little information on residue cover, biomass production, glucosinolate concentration, and glucosinolate production with winter rape grown as a green manure is available. In field trials in southern Idaho, ‘Aspen,’ ‘Bridger,’ ‘Cascade,’ ‘Dwarf Essex,’ and ‘Humus’ winter rape were planted in mid-August and incorporated the following spring in late April or early May. All five cultivars provided > 80% fall, winter, and early spring residue cover. Winter rape dry weight just before incorporation was 2,880 to 4,462 kg/ha in 1994 and 5,438 to 7,837 kg/ha in 1995. The major glucosinolate in roots of all five cultivars was phenylethyl glucosinolate; the major glucosinolates in shoots were 4-pentenyl, 2-hydroxybutenyl, 3-butenyl, and 2-hydroxypentenyl glucosinolate. Glucosinolate concentrations varied between years, but concentrations were higher in Dwarf Essex and Humus than in Aspen both years. Glucosinolate production per hectare also was highest in Dwarf Essex and Humus and lowest in Aspen. Dwarf Essex and Humus produced higher amounts of isothiocyanate (ITC) and oxazolidinethione (OZT)-producing glucosinolates than Aspen, Bridger, or Cascade, and therefore may be better biofumigants.

scholarly journals Quantifying Loss Caused by Ray Blight Disease in Tasmanian Pyrethrum Fields

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1116-1121 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Paul Esker ◽  
Phillip Dixon ◽  
Frank Hay ◽  
Tim Groom ◽  
...  
Keyword(s):  
Dry Weight ◽  
Tobit Regression ◽  
Intensity Measures ◽  
Site Specific ◽  
Growing Seasons ◽  
Ray Blight ◽  
Censored Regression Model ◽  
Blight Disease ◽  
Attainable Yield ◽  
Commercial Fungicide

The efficacy of newly implemented fungicide recommendations on reducing the intensity of ray blight disease caused by Phoma ligulicola to achieve site-specific attainable yield potentials in Tasmanian pyrethrum fields was quantified over two seasons in 46 and 51 fields during the 2003 and 2004 growing seasons, respectively. Disease intensity and yield in two plots (10 × 24 m), one following the commercial fungicide protocol recommendations and the second receiving no fungicide, were assessed in each pyrethrum field. The commercial fungicide protocol consisted of one application of azoxystrobin at 150 g a.i./ha, followed by two applications of a tank mixture of difenoconazole at 125 g a.i./ha and chlorothalonil at 1,008 liters a.i./ha at 14- to 21-day intervals. This program resulted in significant decreases in defoliation severity and the incidence of stems and flowers with ray blight, and increases in the height of stems and number of flowers produced per stem in October and November. In plots receiving the commercial fungicide protocol, the dry weight of flowers was increased by 76 and 68% in 2003 and 2004, respectively. Moreover, pyrethrin yield increased by 81 and 78% when the commercial fungicide protocol was used compared with the nontreated plots. Tobit regression was used to examine the relationships and thresholds among disease intensity measures (defoliation severity, stem severity, and incidence of flowers with ray blight) assessed just prior to harvest. This regression utilized a left-censored regression model to define subminimal thresholds, as none of the disease intensity measures could be less than 0. Defoliation severity had a threshold of 35.3% before stem severity linearly increased and a threshold of 38.2% before the incidence of flowers with ray blight linearly increased. Finally, the threshold for stem severity was 13.7% before the incidence of flowers with ray blight linearly increased. These thresholds can be used to assist growers in making disease management decisions with the objective of minimizing loss of flowers by maintaining defoliation severity below the critical point at which the incidence of flowers with ray blight begins to linearly increase.

scholarly journals Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Lirong Chen ◽  
Yuqiu Guo ◽  
Xiaoyue Li ◽  
Kuijie Gong ◽  
Kaichang Liu
Keyword(s):  
Radical Scavenging ◽  
Dry Weight ◽  
Sodium Cholate ◽  
Free Form ◽  
Functional Activities ◽  
Free Phenolics ◽  
The Difference ◽  
Different Color ◽  
Waxy Corn

AbstractThe polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 µg/g DW (dry weight), which was slightly higher (P > 0.05) than that of the total bound form (6276.65 µg/g DW). The total free flavonoid content was 5850.09 µg/g DW, which was higher (P < 0.05) than that of the total bound form (4874.51µg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86−100 % and 70−78 % of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100 % of the ferric reducing capacity. The free phenolics in fresh waxy corn showed better (P < 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed better (P < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

scholarly journals Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

2020 ◽  
Author(s):  
Lirong Chen ◽  
Yuqiu Guo ◽  
Xiaoyue Li ◽  
Kuijie Gong ◽  
Kaichang Liu
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging ◽  
Dry Weight ◽  
Sodium Cholate ◽  
Free Form ◽  
Functional Activities ◽  
Free Phenolics ◽  
The Difference ◽  
Waxy Corn

Abstract The polyphenol distribution in fresh waxy corns of different color varieties and their functional activities, which may be useful for treating various chronic diseases, were investigated. The in vitro antioxidant activity, and hypoglycemic and hypocholesterolemic effects of the free and bound corn phenolics were determined to evaluate the edible value of fresh waxy corn. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 6637.73 μg/g DW (dry weight), which was slightly higher (P >0.05) than that of the total bound form (6276.65 μg/g DW). The total free flavonoid content was 5850.09 μg/g DW, which was higher (P < 0.05) than that of the total bound form (4874.51μg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86-100% and 70-78% of the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100% of the ferric reducing capacity. The free phenolics in fresh waxy corn showed significantly better (P < 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed significantly better (P < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.Keywords: fresh waxy corn; polyphenol; antioxidant activity; hypoglycemic; hypocholesterol

scholarly journals 894 PB 502 COMPARISON OF TWO CULTURE VESSEL ENCLOSURES ON THE GROWTH OF POTATO IN VITRO

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 562a-562
Author(s):  
N.C. Yorio ◽  
C.L. Mackowiak ◽  
B.V. Peterson ◽  
R.M. Wheeler
Keyword(s):  
Dry Weight ◽  
Culture Vessel ◽  
Fresh Weight ◽  
White Potato ◽  
Fluorescent Lamps ◽  
Plantlet Growth ◽  
Nodal Cuttings ◽  
The Difference ◽  
Air Exchange

In vitro growth of white potato (Solanum tuberosum L.) cv. Norland was investigated comparing two types of culture vessel enclosures. Nodal cuttings were aseptically transferred to 25 × 150 mm glass culture vessels containing a solidified medium consisting of Murashige and Skoog salts, 1% sucrose, and pH adjusted to 5.8. The vessels were capped with loose-fitted (1 cm gap between the top of the vessel and the top of the cap) Magenta 2-way caps or Bellco Kap-uts with calculated air changes hr-1 of 2.25 and 1.43, respectively. Instantaneous PPF attenuations of 15% for Magenta caps and 23% for Bellco caps were also measured. The cultures were maintained for 28 d in an environmental growth chamber under Daylight fluorescent lamps with a 16 hr light/8 hr dark photoperiod, 200 μmol m-2s-1 PPF maintained for each cap type, constant 23 C, 65% relative humidity, and CO2 enrichment of 1000 μmol mol-1 external to the culture vessels. Results showed that increased plantlet height, fresh weight, and dry weight was obtained for plantlets cultured with Magenta caps. The differences in growth and internal CO2 concentration of the vessels correlated well with the difference in air exchange rates, suggesting that increased air exchange of culture vessels resulted in increased mixotrophic plantlet growth.

scholarly journals Phenolics and related in vitro functional activities of different varieties of fresh waxy corn: a whole grain

2019 ◽  
Author(s):  
Lirong Chen ◽  
Yuqiu Guo ◽  
Xiaoyue Li ◽  
Kuijie Gong ◽  
Kaichang Liu
Keyword(s):  
Radical Scavenging ◽  
Dry Weight ◽  
Sodium Cholate ◽  
Free Form ◽  
Functional Activities ◽  
Free Phenolics ◽  
The Difference ◽  
Different Color ◽  
Waxy Corn

Abstract The polyphenol distribution in fresh waxy corns of different color varieties and their in vitro functional activities, which may be useful for treating various chronic diseases, were investigated. The colored varieties contained more phenols than the common varieties (white and/or yellow). The total free phenolic acid content of the six varieties was 3151.57 μg/g DW (dry weight), which was slightly higher ( p >0.05) than that of the total bound form (3028.24 μg/g DW). The total free flavonoid content was 5850.09 μg/g DW, which was higher ( p < 0.05) than that of the total bound form (4874.51μg/g DW). No bound anthocyanin was detected in the methanol extracts of the tested varieties. For all the varieties, free polyphenols contributed 86-100% and 70-78% of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging abilities, respectively, and 100% of the ferric reducing capacity. The free phenolics in fresh waxy corn showed significantly better ( p < 0.05) hypoglycemic effect than the bound form in terms of inhibition of α-amylase activity, whereas the bound phenolics of most varieties showed higher α-glucosidase inhibitory activity than the free forms. The free phenolics showed significantly better ( p < 0.05) glycocholesterol binding than the bound form for all varieties. The bound polyphenols showed better sodium cholate and taurocholate binding than the free form for most varieties. In conclusion, the difference between free and bound polyphenol content and functional activities indicates that fresh waxy corn can be potentially used for the development of functional food.

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