scholarly journals Factors Influencing Airborne Conidial Concentrations of Alternaria panax in Cultivated American Ginseng Gardens

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1311-1316 ◽  
Author(s):  
S. N. Hill ◽  
M. K. Hausbeck
Keyword(s):  
Relative Humidity ◽  
American Ginseng ◽  
Leaf Blight ◽  
Leaf Wetness ◽  
Common Disease ◽  
Panax Quinquefolium ◽  
Growing Seasons ◽  
Weather Parameters ◽  
Alternaria Panax ◽  
Disease Pressure

Leaf blight, caused by Alternaria panax, is the most common disease of cultivated ginseng and is an annual threat. To determine the influence of weather parameters on airborne conidial concentrations (ACCs), 3- and 4-year-old commercial American ginseng (Panax quinquefolium) gardens were monitored from mid-May to September for two growing seasons. Hourly concentrations of airborne A. panax conidia were enumerated using a Burkard volumetric spore sampler. The hourly averages of air temperature, rainfall, leaf wetness, and relative humidity were also collected. Fungicides were not applied. The incidence of leaf blight was assessed in predetermined areas of the monitored gardens. Disease pressure from A. panax was high in 2005 and 2006 and resulted in crop defoliation. Each year, ACCs were detected beginning in late May and continued through the growing season. Daily conidial concentrations followed a diurnal pattern and were greatest during periods of rapidly decreasing relative humidity. Relative humidity was negatively correlated to hourly ACCs. Each year, hourly ACCs were negatively correlated to leaf wetness and rainfall. A positive correlation was detected for hourly ACCs following 16 h or more of rainfall. A significant correlation was observed between hourly ACCs and temperature.

scholarly journals Influence of weather parameters on alternaria leaf blight severity of makhana under the agro-climate of Koshi region of Bihar

2021 ◽  
Vol 23 (1) ◽  
pp. 54-59
Author(s):  
SANTOSH KUMAR ◽  
MD. NADEEM AKHTAR ◽  
SANTOSH KUMAR ◽  
MAHESH KUMAR ◽  
TRIBHUWAN KUMAR
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Disease Severity ◽  
Infection Process ◽  
Leaf Blight ◽  
Alternaria Leaf Blight ◽  
Weather Parameters ◽  
Maximum Temperatures ◽  
Blight Disease ◽  
Cent Disease

Weather parameters play a pivotal role in the infection process and spread of pathogen. It also influences the expression of susceptibility/resistance of the host plant during post-infection phases. Therefore, an experiment was conducted for two consecutive cropping seasons (2018 &2019) to study the influence of weather parameters such as temperature, humidity, rainfall and wind direction on the emergence of alternaria leaf blight of makhana in Koshi region of Bihar. Maximum per cent disease severity of alternarialeaf blightwas observed during the peak monsoon months (June to August). Highest disease severity of leaf blight (14.80% & 15.7%) was observed in the mid June during crop season, 2018 and 2019. High temperature (36.9oC & 38.1oC), and relative humidity (94% & 96.4%) of both the year 2018 and 2019 were found correlated with higher severity to alternaria leaf blight. Similarly average HTR values (3.1) were also found correlated with the average high temperature and relative humidity of both years (2018 and 2019) in terms of severity of leaf blight disease. Maximum temperatures, relative humidity and rainfall exhibited strong positive linear relationship and influenced the occurrence of alternaria leaf blight disease significantly. We also developed a geo-phytopathological model for the prediction of alternaria leaf blight disease of makhana on the basis of congenial mean temperature and relative humidity.

scholarly journals Evaluation of TOM-CAST in Timing Fungicide Sprays for Management of Alternaria Blight on American Ginseng

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1611-1615 ◽  
Author(s):  
S. N. Hill ◽  
M. K. Hausbeck
Keyword(s):  
Disease Severity ◽  
Seed Yield ◽  
American Ginseng ◽  
Treatment Programs ◽  
Panax Quinquefolium ◽  
Copper Hydroxide ◽  
Foliar Disease ◽  
Yield And Quality ◽  
Alternaria Panax ◽  
Seed Coats

Alternaria panax incites blighting of the foliage, peduncles, and drupes of cultivated American ginseng (Panax quinquefolium). A disease forecaster (TOM-CAST), originally developed to predict leaf blight caused by A. solani on tomato, was evaluated for management of A. panax in commercial ginseng gardens. For 3 years, fungicide sprays initiated by TOM-CAST (using 10 and 15 disease severity value thresholds) were compared with sprays applied at 7- and 10-day intervals. Three fungicide programs were evaluated: (i) chlorothalonil alone, (ii) chlorothalonil alternated with pyraclostrobin, and (iii) copper hydroxide alternated with pyraclostrobin. As many as 10 fewer fungicide applications were made when using TOM-CAST or the 10-day programs. Although select TOM-CAST treatment programs were comparable with the 7-day schedule in limiting foliar disease, only the 7-day applications adequately protected drupe and seed yield. Both A. panax and A. alternata were recovered from drupe tissues and seed coats. Only A. alternata was recovered from endosperm halves. Ginseng seed yield and quality is an important consideration when assessing fungicide programs.

Ginsenosides as host resistance factors in American ginseng (Panax quinquefolius)

2002 ◽  
Vol 80 (5) ◽  
pp. 557-562 ◽  
Author(s):  
R W Nicol ◽  
J A Traquair ◽  
M A Bernards
Keyword(s):  
Fungal Growth ◽  
Hyphal Growth ◽  
Pathogenic Fungi ◽  
Dry Weight ◽  
American Ginseng ◽  
Panax Quinquefolius ◽  
Trichoderma Spp ◽  
Growing Seasons ◽  
Alternaria Panax

American ginseng (Panax quinquefolius L.) produces a number of saponins (ginsenosides). The ability of saponins from cultivated American ginseng to inhibit fungal growth in vitro was evaluated. Fungi exhibited a range of sensitivity to ginsenosides extracted from roots collected in two growing seasons. Important root pathogens (Cylindro carpon destructans, Fusarium solani, and Fusarium oxysporum) were unaffected by these phytochemicals at a concentration of 1 mg·mL–1, whereas the growth of Alternaria panax and nonpathogenic Trichoderma spp. was inhibited. The same trend emerged when a range of ginsenoside concentrations was used on a subset of fungi. Hyphal growth of C. destructans was unaffected up to a level of ginsenosides approaching that found in roots (i.e., ~ 3% dry weight). The growth of F. solani was significantly less than that of the control at saponin concentrations of 0.1 to 3.0% (w/v), but was relatively unaffected in comparison to growth of Trichoderma hamatum and A. panax.Key words: ginsenoside, antifungal, pathogenic fungi, disease resistance, phytochemicals.

scholarly journals Pseudoginsenoside F11, a Novel Partial PPARγAgonist, Promotes Adiponectin Oligomerization and Secretion in 3T3-L1 Adipocytes

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Guoyu Wu ◽  
Junyang Yi ◽  
Ling Liu ◽  
Pengcheng Wang ◽  
Zhijie Zhang ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Side Effects ◽  
Hormone Receptor ◽  
Adipocyte Differentiation ◽  
American Ginseng ◽  
Nuclear Hormone Receptor ◽  
Targeted Therapeutics ◽  
Panax Quinquefolium ◽  
Master Regulator

PPARγis a nuclear hormone receptor that functions as a master regulator of adipocyte differentiation and development. Full PPARγagonists, such as the thiazolidinediones (TZDs), have been widely used to treat type 2 diabetes. However, they are characterized by undesirable side effects due to their strong agonist activities. Pseudoginsenoside F11 (p-F11) is an ocotillol-type ginsenoside isolated fromPanax quinquefolium L.(American ginseng). In this study, we found that p-F11 activates PPARγwith modest adipogenic activity. In addition, p-F11 promotes adiponectin oligomerization and secretion in 3T3-L1 adipocytes. We also found that p-F11 inhibits obesity-linked phosphorylation of PPARγat Ser-273 by Cdk5. Therefore, p-F11 is a novel partial PPARγagonist, which might have the potential to be developed as a new PPARγ-targeted therapeutics for type 2 diabetes.

scholarly journals Influence of Environment on Atmospheric Concentrations of Peronospora antirrhini Sporangia in Field-Grown Snapdragon

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1060-1066 ◽  
Author(s):  
J. M. Byrne ◽  
M. K. Hausbeck ◽  
L. E. Sconyers
Keyword(s):  
Average Length ◽  
Pathogen Resistance ◽  
Management Program ◽  
Leaf Wetness ◽  
Environmental Cues ◽  
Total Rainfall ◽  
Growing Seasons ◽  
Positive Correlations ◽  
Total Spore Count ◽  
Atmospheric Concentrations

Hourly concentrations of airborne sporangia of Peronospora antirrhini at a commercial snapdragon farm were investigated over three growing seasons to determine the influence of the environment on their occurrence and concentration. Hourly concentrations of sporangia of P. antirrhini were estimated using a Burkard volumetric spore sampler. Atmospheric sporangial concentrations followed a diurnal pattern and were greatest during 0500 to 1200 h. Minimum daily temperatures <10.0°C appeared to have a moderate limiting effect on atmospheric sporangial concentrations, whereas temperatures <6.0°C had more severe limiting effects. Maximum daily temperatures ≥30.0°C limited concentrations of atmospheric sporangia. Long dew periods (≥6 h) were associated with relatively large sporangia releases. On 69 days (1999 to 2001), the total number of sporangia trapped was >100/m3/day, and the average length of leaf wetness duration prior to these releases was 11 h. Consecutive days with short leaf wetness periods were associated with low atmospheric sporangial concentrations. Significant positive correlations (P = 0.0502 and P = 0.0174) were found between total rainfall and total spore count for both research plots in 2000. Information gained from this study will contribute to the development of a disease management program that utilizes environmental cues to prompt fungicide applications, thus increasing the efficiency of fungicide programs and delaying the development of pathogen resistance.

Seasonal Incidence of Pulse Aphid (Aphis craccivora Koch.) and its Natural Enemies on Field Pea (Pisum sativum L.) in Relation to Some Abiotic Factors in Alluvial Zone of West Bengal

2021 ◽  
Author(s):  
S. Pal ◽  
S. Samanta ◽  
A. Banerjee
Keyword(s):  
Relative Humidity ◽  
Pisum Sativum ◽  
Natural Enemies ◽  
West Bengal ◽  
Insect Pests ◽  
Field Pea ◽  
Pest Population ◽  
Pisum Sativum L ◽  
Aphis Craccivora Koch ◽  
Weather Parameters

Background: Field pea, Pisum sativum L. is an important winter-season pulse crop. It is subjected to damage by both field and storage insect pests and approximately 10-15 per cent reduction in yield was reported due to the infestation of different insect pests. Among these, pulse aphid (Aphis craccivora Koch.) affects plant physiology directly by removal of nutrients or indirectly by dispersal of various viral diseases. The present investigation has been aimed to study the seasonal fluctuations of aphids and their natural enemies as well as their correlation. Another objective was to know the effect of various weather parameters on pulse aphids and their natural enemies which ultimately would be helpful to develop a forewarning model.Methods: The field experiment was conducted at the A-B Block Farm of Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal using two varieties of field pea (KPMR 935 and IFPD 122) during rabi seasons of two consecutive years of 2017-18 and 2018-19 following a Randomized Block Design with three replications. After recording the total population of both pests (nymphs and adults) and their natural enemies across the season, the mean population was worked out and used for correlation and regression studies along with the weather parameters. Result: Maximum aphid population was noticed during the peak pod formation stage of the crop irrespective of the varieties. The pest population was very strongly correlated with the incidence of coccinellid and ant population in both test varieties. Among the weather parameters, both maximum and minimum temperature and sunshine hour showed a positive correlation with the pest population and their natural enemies but relative humidity and rainfall showed a negative correlation. Regression studies indicated that temperature and relative humidity were the most influencing factors over the incidence of aphid in both the seasons.

scholarly journals Reproductive performance of spiralling whitefly on guava and impact of weather parameters on its immature stages

2018 ◽  
Vol 15 (2) ◽  
pp. 207-214
Author(s):  
I Hossain ◽  
MMH Khan ◽  
SMH Jahan
Keyword(s):  
Relative Humidity ◽  
Negative Correlation ◽  
Reproductive Performance ◽  
Significant Positive Correlation ◽  
Instar Nymph ◽  
Maximum Temperature ◽  
Immature Stages ◽  
Positive Correlation ◽  
Aleurodicus Dispersus ◽  
Weather Parameters

The study was conducted to know the reproductive performance of spiralling whitefly on guava. Number of colony, eggs, 1st instar, 2nd instar, 3rd instar and 4th instar nymphs per five leaves ranged from 6 to 15, 8 to 32, 0 to 44, 0 to 22, 0 to 45 and 0 to 28, respectively. Maximum number of adults and nymphs were found in the month of January. Highest longevity of Aleurodicus dispersus (21.5 days) was recorded in adult while the lowest was in 2nd instar nymph (6.4 days). The number of colony/leaf and number of 3rd and 4th instar nymphs of A. dispersus had significant positive correlation with minimum and maximum temperature while non-significant positive correlation is observed between the number of egg/colony, the number 1st and 2nd instar nymphs with minimum and maximum temperature. A. dispersus showed nonsignificant positive correlation with minimum and maximum relative humidity regarding number of colony/leaf, 2nd instar nymph while nonsignificant negative correlation with 4th instar nymph.SAARC J. Agri., 15(2): 207-214 (2017)

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