scholarly journals Influence of weather variables on the development of pearl millet downy mildew

2021 ◽  
Vol 21 (1) ◽  
pp. 76-79
Author(s):  
ASHLESHA ATRI ◽  
HARPREET SINGH
Keyword(s):  
Relative Humidity ◽  
Downy Mildew ◽  
Pearl Millet ◽  
Negative Correlation ◽  
Minimum Temperature ◽  
Disease Incidence ◽  
Significant Negative Correlation ◽  
Control Measures ◽  
Maximum Temperature ◽  
Weather Variables

The present study was undertaken during 2016 to 2018 to find out the effect of different weather variables on the initiation and development of downy mildew in pearl millet in Punjab. The maximum temperature ranged from 32.8ºC to 36.9ºC and minimum temperature ranged from 17.2ºC to 27.8ºC during the crop season. The correlation analysis showed significant negative correlation of maximum temperature (r = -0.665*), minimum temperature (r = -0.776**), wind speed (r = -0.898**), rainfall (r = -0.625**) and non-significant negative correlation of evening relative humidity (r = -0.523) with downy mildew incidence. The positive correlation with morning relative humidity (r = 0.871**) was significant and sunshine hours (r = 0.321) were non-significant with per cent disease incidence. A multiple regression model was developed using two years (2016 and 2017) data to predict the occurrence of downy mildew with R2 = 0.981, indicating that all weather parameters contributed 98.1 per cent towards disease development. The model was validated with 2018 data which shows that equation can be used in the disease forecasting for taking timely actions for control measures.

scholarly journals Effect of meteorological parameters on Karnal bunt incidence in wheat under different agroclimatic zones of Punjab

2022 ◽  
Vol 24 (1) ◽  
Author(s):  
SARABJOT KAUR SANDHU ◽  
ANURAG ATTRI ◽  
RITU BALA
Keyword(s):  
Relative Humidity ◽  
Negative Correlation ◽  
Significant Positive Correlation ◽  
Meteorological Parameters ◽  
Disease Incidence ◽  
Karnal Bunt ◽  
Maximum Temperature ◽  
Wheat Crop ◽  
Sunshine Hours ◽  
Rainy Days

To quantify the effect of meteorological parameters on incidence of Karnal bunt in wheat crop, an investigation was done using 9 to 12 season’s data of Bathinda and Ludhiana stations of Punjab. Maximum temperature during March in range of 25-31oC, minimum temperature of February (8.5-11.0oC), morning and evening relative humidity of March in range of 85-95 and 40-60 per cent respectively, rainfall more than 25 mm with sunshine hours 5.5-9.0 hrs/day during mid February to mid March favour Karnal bunt in wheat crop. Maximum temperature of March showed significant negative correlation with incidence of Karnal bunt whereas minimum temperature of February showed significant positive correlation with disease incidence at both locations. Morning and evening relative humidity showed significant positive correlation with disease incidence. Rain amount and rainy days during mid February to mid March significantly influenced disease incidence. Sunshine hours had negative correlation with disease incidence. Backward multiple linear regression (BMLR) analysis indicated maximum temperature, rainfall and sunshine hours play significant role in Karnal bunt incidence at Ludhiana. However, at Bathinda, maximum temperature, evening time relative humidity, rain amount and rainy days played significant role.

Impact of abiotic factors on seasonal incidence of insect pests of soybean

2016 ◽  
Author(s):  
R. K. Kalyan ◽  
O. P. Ameta
Keyword(s):  
Relative Humidity ◽  
Negative Correlation ◽  
Positive Impact ◽  
Significant Negative Correlation ◽  
Maximum Temperature ◽  
Larval Population ◽  
Positive Correlation ◽  
Pod Borer ◽  
Rain Fall ◽  
Tobacco Caterpillar

The study was carried out at Agricultural Research Station- Banswara during kharif-2012 and 2013. During the years 2012 and 2013, the peak population of white fly was observed in the 35th SMW and 37th SMW, respectively. The population of whitefly had a positive correlation with the maximum temperature and sunshine (hours) while, negative correlation with rain fall and morning and evening relative humidity during both the years but significant only during 2013. The maximum population of semilooper was recorded in the 36th SMW and 39th SMW, respectively. The semilooper exhibited a significant and positive correlation with minimum temperature, morning evening humidity and rain fall during both the years. The highest girdle beetle damage was recorded in the 35th SMW and 37th SMW, respectively; whereas the maximum incidence of gram pod borer was recorded in the 36th SMW and 39th SMW, respectively. The larval population of gram pod borer exhibited a significant negative correlation with sun shine and minimum temperature during experimental period; whereas, it exhibited a significant and positive correlation with rainfall and relative humidity during both the years. The maximum incidence of tobacco caterpillar in soybean crop was recorded during 41st SMW and 42nd SMW, respectively. The maximum temperature and sun shine hours showed a significant positive correlation with the larval population of tobacco caterpillar while, significant negative correlation with rainfall during both the years. The regression equation indicated that rainfall had significant negative and positive impact on population of white fly and semilooper, respectively. Whereas, maximum temperature had significant positive impact on population of tobacco caterpillar while rainfall had significant negative effect.

scholarly journals Environmental Factors Affecting Rose Downy Mildew and Development of a Forecasting Model for a Nursery Production System

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 732-738 ◽  
Author(s):  
B. J. Aegerter ◽  
J. J. Nuñez ◽  
R. M. Davis
Keyword(s):  
Downy Mildew ◽  
Negative Correlation ◽  
Disease Incidence ◽  
Environmental Parameters ◽  
Leaf Wetness ◽  
Cumulative Number ◽  
Weather Variables ◽  
Factors Affecting ◽  
Incidence Data ◽  
Nursery Production

The effect of various environmental parameters on rose downy mildew caused by Peronospora sparsa was determined under controlled conditions and in the field. In growth chambers, optimal temperatures for infection and colonization of rose leaves were 15 to 20°C and 20 to 25°C, respectively. At optimal temperatures, infection required only 2 h of leaf wetness, although disease severity increased significantly with an increasing duration of leaf wetness up to 10 h. Infection of leaves occurred at temperatures as low as 5°C with 8 h of leaf wetness. The latent period of infection varied from 4 to 7 days. Weather and disease incidence data collected from natural field epidemics were used in the development of a predictive model of rose downy mildew. Logistic regression was used to identify those weather variables that explained the largest portion of the variation in disease incidence. The optimum regression model incorporated three weather variables calculated as cumulative totals over the previous 10 days: (i) hours of leaf wetness when temperatures were less than 20°C (positive correlation); (ii) hours between 15 and 20°C (negative correlation); and (iii) hours when temperatures exceeded 30°C (negative correlation). The simplest model, which was also a good fit, included only the 10-day cumulative number of hours of leaf wetness. The critical number of hours of leaf wetness for disease development was an average of 8.4 h per day over 10 days.

scholarly journals Seasonal Incidence and Effect of Abiotic Factors on Population Dynamics of Sucking Insect Pest Complex of Groundnut

2021 ◽  
pp. 10-17
Author(s):  
K. Shamili Dhatri ◽  
M. S. V. Chalam ◽  
A. Rajesh ◽  
B. Ramana Murthy ◽  
N. C. Venkateswartlu
Keyword(s):  
Negative Correlation ◽  
Minimum Temperature ◽  
Significant Positive Correlation ◽  
Insect Pests ◽  
Abiotic Factors ◽  
Insect Pest ◽  
Significant Negative Correlation ◽  
Maximum Temperature ◽  
Seasonal Incidence ◽  
Positive Correlation

Studies on seasonal incidence of sucking insect pests carried out with three dates of sowing viz., early (July 15th), normal (July 30th) and late (August 15th) revealed that the incidence of leafhoppers, aphids and thrips started from 5 to 14 DAS (days after sowing) and continued till harvesting. In early sown crop, the incidence of leafhoppers started from 31 SW and incidence of aphids and thrips started from 30 SW and continued up to 42 and 43 SW for leafhoppers and aphids, respectively and 41 SW for thrips. In normal sown crop, incidence of leafhoppers and aphids started from 32 SW and incidence of thrips started from 31 SW and continued till the end of 45 SW for all the three pests. In late sown crop, the incidence of leafhoppers started from 35 SW and incidence of aphids and thrips started from 34 SW and continued up to 46 and 47 SW for leafhoppers and aphids, respectively and 46 SW for thrips. Correlation studies revealed that incidence of leafhoppers exhibited significant negative correlation with maximum temperature (r = -0.467, -0.442 and -0.464) and rainfall (r = -0.518, -0.529 and -0.742) during all the three dates of sowing (early, normal and late, respectively) and significant negative correlation with minimum temperature in late sown crop (r = -0.448). Aphids exhibited significant negative correlation with maximum temperature (r = -0.469, -0.521 and -0.472) and rainfall (r = -0.443, -0.450 and  -0.721) in all the three dates of sowing (early, normal and late, respectively) while significant negative correlation with minimum temperature in early and late sown crop with r values -0.519 and -0.324.  Thrips exhibited significant positive correlation with maximum temperature (r = 0.522, 0.459 and 0.447), significant negative correlation with rainfall (r = -0.458, -0.465 and -0.451) during three dates of sowing (early, normal and late, respectively) while significant negative correlation with relative humidity in early sown crop (r = -0.616) and significant positive correlation with minimum temperature in early sown crop (r = 0.463).

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)

scholarly journals Weather parameters vulnerability on tea production in north western Himalaya, India

2016 ◽  
Vol 8 (4) ◽  
pp. 2262-2267
Author(s):  
Parmod Verma ◽  
Ranbir Singh Rana ◽  
Ramesh Ramesh ◽  
Ranu Pathania
Keyword(s):  
Relative Humidity ◽  
Minimum Temperature ◽  
Positive Relationship ◽  
Western Himalaya ◽  
Green Leaf ◽  
Maximum Temperature ◽  
Leaf Yield ◽  
Tea Production ◽  
Weather Parameters ◽  
June July

The study assessed the sensitivity of weather parameters with respect to total green leaf and two leaves and bud (T & B) productivity of tea crop {Camellia sinensis (L.) Kuntze}. The maximum temperature ranging from 20.0 to 29.0 oC during March, May, August and September showed positive relationship with values ranging from 0.26 to 3.38 and 0.22 to 3.22 for green leaf and T & B yield, respectively. Similarly, minimum temperature ranging from 9.1 to 20.0 oC during March and July to October found positive 0.001 to 2.93 and 0.28 to 2.91 for green leaf and T & B productivity, respectively. The mean monthly rainfall amounting 52.7 to 664.7 mm during March, May, July to October and 52.7 to 488.4 mm during June, July, September and October also showed positive sensitivity with values ranging from 0.03 to 0.33 and 0.007 to 0.35 for green leaf and T & B yield, respectively. The relative humidity ranging between 41.2 to 77.3% during April to May for green leaf yield (0.32 to 1.71) and during April to May and October for two leaf and bud yield (0.00 to 1.70) showed positive relationship. So, maximum and minimum temperature between 20.0 to 29.0 oC and 9.1 to 20.0 oC, respectively with rainfall of 52.7 to 488.4 mm and relative humidity 41.2 to 77.3% are the most beneficial weather parameters for tea cultivation at Palampur conditions.

scholarly journals Impact of abiotic factors on build-up of citrus psylla, Diaphorina citri Kuwayama population in Punjab, India

2014 ◽  
Vol 6 (2) ◽  
pp. 371-376 ◽  
Author(s):  
Hijam S. Devi ◽  
D. R. Sharma
Keyword(s):  
Relative Humidity ◽  
Disease Transmission ◽  
Minimum Temperature ◽  
Abiotic Factors ◽  
Winter Season ◽  
Seasonal Abundance ◽  
Maximum Temperature ◽  
Weak Links ◽  
Diaphorina Citri ◽  
Citrus Psylla

Seasonal abundance of citrus psylla (Diaphorina citri) Kuwayama was studied on Kinnow mandarin under Punjab conditions during 2012 and 2013. Population of D. citri was present throughout the year but only adults found surviving during December and February. There was no nymphal population when maximum temperature was > 39°C or < 7°C. Two population peaks of nymphs wer e observed, first in April-May and second in August- September. Thereafter, there was abrupt decline in nymphal population during June and July during both the years when the weather conditions i.e. maximum, minimum temperature (°C), relative humidity (%), rainfall (m m) and sunshine (hrs) ranged from 24.4-44, 22.4-31.8, 25.5-100, 0-108.0 and 0-13.5, respectively. Highest peaks of adult were found during May followed by June. With the decrease in temperature from the end of September, the population of D. citri started to decrease and reached its lowest during winter season. Correlation analysis for both the years indicated that maximum and minimum temperature, sunshine and rainfall were positively correlated with nymphal, adult and mixed population but the effect of rainfall on adult population was non-significant, while relative humidity was negatively correlated. The study is useful to find out the weak links of psyllid populations in relation to abiotic factors and that could be exploited to curb its infestation and disease transmission.

scholarly journals Abundance, damage severity and management of guava mealybug, ferrisia virgata ckll

2019 ◽  
Vol 16 (2) ◽  
pp. 73-82
Author(s):  
MMH Khan
Keyword(s):  
Relative Humidity ◽  
Leaf Area ◽  
Negative Correlation ◽  
Untreated Control ◽  
Soap Solution ◽  
Maximum Temperature ◽  
Water Spray ◽  
Positive Correlation ◽  
Middle Leaf ◽  
Percent Mortality

The research was carried out to know the abundance and damage severity of mealybug on sarupkathi variety of guava and to evaluate the efficacy of jet powder and Fighter 2.5EC for suppressing populations of mealybug during January to October 2014. Results revealed that the highest number of guava mealybug was observed on middle leaf (42/leaf) while the lowest number was on lower leaf (13/leaf). The highest percent leaf area covered by mealybug was found on middle leaf (78%) while the lowest was on fruit (18%). Maximum temperature and relative humidity had a positive correlation on the mealybug population while the rainfall showed a negative correlation. The highest percent mortality was observed in T2 treatment (Jet powder applied @ 5.0 g L-1 of water) at 24 HAT (hours after treatment) (86.05%) and 48 HAT (93.83%), respectively. At 72 HAT, the highest percent mortality was observed T3 treatment (Jet powder applied @ 7.5 g L-1 of water). In case of insecticidal control, the highest percent mortality was observed in T2 (100%) and T3 (100%) treatments, respectively followed by T1 (98.03%) at 24 HAT. Similar trends were also observed among all treatments at 48 HAT and 72 HAT, respectively. No significant differences were found among three doses of Fighter 2.5EC. The lowest percent mortality of mealybug population was found in T4 (Water spray forcibly) at 24 HAT, 48 HAT and 72 HAT, respectively. No mortality was recorded in untreated control at different HAT in both application of soap solution and insecticides. SAARC J. Agri., 16(2): 73-82 (2018)

scholarly journals Use of Weather Variables to Quantify Sorghum Ergot Potential in South Africa

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 26-29 ◽  
Author(s):  
N. W. McLaren ◽  
B. C. Flett
Keyword(s):  
Minimum Temperature ◽  
Pollen Viability ◽  
Breakdown Point ◽  
Field Trials ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Weather Variables ◽  
Data Set ◽  
Study Results

Quantification of resistance to ergot requires that the observed ergot severity within a sorghum line be compared with expected ergot severity (ergot potential) to compensate for differences in environmental favorability for the disease among flowering dates and seasons. The ergot potential required to induce the onset of disease is referred to as the ergot breakdown point of that line. In earlier studies, the ergot potential of a specific flowering date was defined as the mean ergot severity in all sorghum heads over all lines in the nursery which commenced flowering on that date in a genetically broad-based sorghum nursery. In this study, results of field trials enabled accurate prediction of ergot potential by using a multiple regression analysis which included three weather variables—namely, pre-flowering minimum temperature (mean of days 23 to 27 pre-flowering), mean daily maximum temperature, and mean daily maximum relative humidity (mean of days 1 to 5 post-flowering; R2 = 0.90; P = 0.91E-5). Evaluation of predicted and observed ergot severity in an independent data set gave an index of agreement of d = 0.94 and R2 = 0.84 (P = 0.106E-4), showing that ergot severity, assuming the presence of viable inoculum, can be accurately predicted. Low pre-flowering minimum temperature was associated with reduced pollen viability, which appeared to be the primary factor predisposing lines to ergot.

scholarly journals Studies on some diseases of fruits and vegetable crops in relation to meteorological parameters

MAUSAM ◽  
2021 ◽  
Vol 51 (3) ◽  
pp. 269-274
Author(s):  
S. V. DATAR ◽  
R. C. DUBEY ◽  
N. CHATTOPADHYAY
Keyword(s):  
Relative Humidity ◽  
Minimum Temperature ◽  
Early Blight ◽  
Meteorological Parameters ◽  
Maximum Temperature ◽  
Vegetable Crops ◽  
Correlation Techniques

The role of different meteorological parameters controlling the incidences of some diseases on tomato, guava and fig grown at Pune and Padegaon in Maharashtra state were studied by graphical superimposition and correlation techniques. Peak infestation of rust on fig was observed in January at Padegaon whereas maximum infestation of fruit canker on guava and early blight on tomato were reported respectively from September to first week of October and September to November at Pune. Increase in maximum temperature was found to increase the infestation of both fruit canker and early blight. Decrease in afternoon relative humidity favoured the infestation of fruit canker and rust. Fall of minimum temperature and rise in bright hours of sunshine also aggravated the incidences of fruit canker and rust respectively.

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