scholarly journals Seasonal abundance and effect of abiotic factors on mango leaf hopper Amritodus atkinsoni (Leth.) population on wild and different cultivators of mango in Jammu region

2013 ◽  
Vol 14 (3) ◽  
pp. 161-168
Author(s):  
Shakha Sharma ◽  
J.S Tara

The mango leaf hopper Amritodus atkinsoni (Leth.) is a very serious pest of mango in J&K region. A series of experiments were conducted on seasonal abundance and the influence of abiotic factors on the incidence of A. atkinsoni on wild and different cultivars of mango viz Dashehari, Langra, Malda and Amarpalli  at Sher-e-Kashmir University of Agricultural Science and Technology Jammu, and, at a mango orchard at Nagbani. The mango hoppers (adults) started appearing with the panicle emergence during the months of February-March and reached its peak ranging from 9.6 to 14.2 in wild and all cultivars under study during May-June. After this the hopper population started declining, but showed another peak (6.6 to 9.8) during August-September which is comparatively lower than the previous one. This clearly indicates that the species breeds twice a year thus a bivoltine species. From September onwards, the hoppers went on declining and vanished by the end of December as they migrate to cracks and crevices of tree trunk and overwinter as adults. Abiotic factors such as maximum temperature (X1), minimum temperature (X2), morning relative humidity (X3), evening relative humidity (X4) and rainfall (X5) had much impact on the growth of hopper population. The hopper population correlated negatively and significantly with morning relative humidity (r = -0.635 to - 0.816) and evening relative humidity (r = - 0.289 to - 0.556) and showed a significant positive correlation with mean maximum temperature (r = 0.692 to 0.915) and minimum temperature (r = 0.590 to 0.881) in wild and all four cultivars, whereas rainfall remained fluctuating throughout the study period thus didn’t show any significant impact.

2014 ◽  
Vol 6 (2) ◽  
pp. 371-376 ◽  
Author(s):  
Hijam S. Devi ◽  
D. R. Sharma

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.


Author(s):  
K. Shamili Dhatri ◽  
M. S. V. Chalam ◽  
A. Rajesh ◽  
B. Ramana Murthy ◽  
N. C. Venkateswartlu

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).


2019 ◽  
Vol 25 (2) ◽  
Author(s):  
Ram Keval ◽  
H.S. Vanajakshi ◽  
Sunil Verma ◽  
Babli Bagri

To study the seasonal incidence of insect pests of pea (P. sativum) the investigation was carried out during Rabi session of 2016-17 and 2017-18, at Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi. The incidence of pests infesting pea was recorded from 50th SMW to 11th SMW. During the observation it was found that P. horticola showed its appearance in the field from 1st to 11th SMW with peak population (71% leaf infestation) in 7th SMW. When population was correlated with abiotic factors it was found that there was positive association with maximum temperature (r = 0.759**), minimum temperature (r = 0.672**), wind speed (r = 0.449).and sunshine hours (r =0.583*) whereas a negative relationship was maintained with morning relative humidity (r =-0.496) and evening relative humidity (r=-0.515), during 2016- 17. Similarly, during 2017-18 there was a positive association with maximum temperature (r = 0.360), minimum temperature (r =0.431), wind speed (r = 0.544*) and sunshine hours(r=0.493) whereas a negative relationship was maintained with morning relative humidity (r =-0.277) and evening relative humidity (r=-0.365).


Author(s):  
Ram Kumar ◽  
P. P. Singh

The present experiment was carried out to access the relationship between population fluctuation of natural enemies and abiotic factors in okra agro-ecosystem at the Research Farm, Tirhut College of Agriculture, Dholi, Muzaffarpur (Bihar). From pooled data of two consecutive Kharif seasons i.e. 2018 and 2019 it was inferred that the highest coccinellids population was registered during 35th standard week (4.56 coccinellids/ 5 plant). Thereafter, the population gradually decreases and reached to 1.19 coccinellids/ 5 plant during 41st standard week i.e. end of the crop. Correlation studies of coccinellids population with abiotic factors indicated that the maximum temperature had positive and highly significant effect on coccinellids. While, minimum temperature and relative humidity at 7 hrs showed positive but non-significant effect on coccinellids. The relative humidity at 14 hrs and rainfall had negative and non-significant correlation with coccinellids population. All the weather parameters together governed 49.90 per cent to the coccinellids population build up (R2 = 0.4990). In case of spider, incidence commenced in 27th standard week however, the maximum population (3.94 spiders/ 5 plant) was observed in 35th standard week. Correlation analysis of spider population with abiotic factors exhibited that the maximum temperature had highly significant and positive effect on spider population. Unlike it, minimum temperature and relative humidity at 7 hrs indicated positive and non-significant effect on spider population. However, the effect of relative humidity at 14 hrs and rainfall on spider population was found negative and non-significant. However, all the prevailing weather parameters together contributed 48.23 per cent towards spider incidence (R2 = 0.4823).


Author(s):  
Yebin Chen ◽  
Zhigang Zhao ◽  
Zhichao Li ◽  
Weihong Li ◽  
Zhipeng Li ◽  
...  

Dengue fever is one of the most common vector-borne diseases in the world and is mainly affected by the interaction of meteorological, human and land-use factors. This study aims to identify the impact of meteorological, human and land-use factors on dengue fever cases, involving the interplay between multiple factors. The analyses identified the statistically significant determinants affecting the transmission of dengue fever, employing cross-correlation analysis and the geo-detector model. This study was conducted in Guangzhou, China, using the data of confirmed cases of dengue fever, daily meteorological records, population density distribution and land-use distribution. The findings highlighted that the dengue fever hotspots were mainly distributed in the old city center of Guangzhou and were significantly shaped by meteorological, land-use and human factors. Meteorological factors including minimum temperature, maximum temperature, atmospheric pressure and relative humidity were correlated with the transmission of dengue fever. Minimum temperature, maximum temperature and relative humidity presented a statistically significant positive correlation with dengue fever cases, while atmospheric pressure presented statistically significant negative correlation. Minimum temperature, maximum temperature, atmospheric pressure and humidity have lag effects on the transmission of dengue fever. The population, community age, subway network density, road network density and ponds presented a statistically significant positive correlation with the number of dengue fever cases, and the interaction among land-use and human factors could enhance dengue fever transmission. The ponds were the most important interaction factors, which might strengthen the influence of other factors on dengue fever transmission. Our findings have implications for pre-emptive dengue fever control.


2017 ◽  
Vol 9 (1) ◽  
pp. 51-54
Author(s):  
Shaik Javed ◽  
K. Vijaya Lakshmi ◽  
C. Narendra Reddy ◽  
B. VidyaSagar ◽  
M. Shanthi

The present investigation was undertaken to find the impact of abiotic factors on seasonal incidence and sucking pest complex of brinjal under field conditions during kharif 2015-2016. The incidence of leaf hopper population (2.80 Lh/L i.e., Leaf hopper mean population/leaf) was noticed during 34th standard week and reached peak by 40th standard week (5.00 Lh/L) (October) whereas the aphid population was noticed during the 34th standard week (3.00 Lh/L) and peak population observed during the 40th standard week (4.60 Lh/L) (October). Correlation studies showed that among the various abiotic factors, maximum temperature showed highly significant positive correlation (r= 0.77) and sunshine hours (r = 0.61) showed significant positive correlation with the leaf hopper population. In case of aphid population, maximum temperature showed significant positive correlation (r = 0.70), rainfall showed highly significant negative correlation (r = -0.74) and relative humidity evening (r = -0.59) showed significant negative correlation with aphid population. The present investigations will give a brief idea about how the abiotic factors influencing the sucking pests of brinjal.


Author(s):  
Nayan Kishor Adhikary ◽  
Krishnendu Roy ◽  
Kajal Kumar Biswas

Sesame is one of the most important oilseed crops in India due to mainly its high quality seed oil and antioxidant properties. Occurrence of foliar diseases, like Alternaria leaf spot and Cercospora leaf spot has become a major constraint in recent years for successful and profitable cultivation of sesame. Field experiments were conducted with sesame var. savitri in a factorial randomized block design with three different dates of sowing with 15 days interval and two different plant protection situations (Protected i.e., treated with disease control protocols and unprotected i.e., control), replicated four times, during two consecutive summer seasons of 2018 and 2019 at Agricultural Experimental Farm, Institute of Agricultural Science, University of Calcutta, Baruipur, South 24 Parganas. The diseases incidence was estimated and correlated with the weather parameters. The average of weather parameters viz., maximum temperature, minimum temperature, relative humidity (morning), relative humidity (evening) and rainfall prior to seven days of disease appearance were considered for study the correlation between the weather factors and the disease. In 2018, disease incidences of the plants shown at third date of sowing (26th April, 2018) in both the protected and unprotected plots had significant (P=.05) but negative correlation with maximum temperature. For plants sown at first date of sowing (27th March, 2018) in 2018 had disease incidences significantly (P=.05) and positively correlated with minimum temperature. However, in 2019, except for the relation between disease incidences in the unprotected plots and maximum temperature, all other disease-temperature correlations were non-significant. Disease incidences were positively and significantly correlated with relative humidity (both morning and evening) in all dates of sowing irrespective of experimental years, except with morning relative humidity at first date of sowing in first year. Total rainfall was positively and significantly correlated with disease incidences at all dates of sowing in 2018; however, such relation was non-significant in 2019. 


2018 ◽  
Vol 15 (2) ◽  
pp. 207-214
Author(s):  
I Hossain ◽  
MMH Khan ◽  
SMH Jahan

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)


2016 ◽  
Vol 8 (4) ◽  
pp. 2262-2267
Author(s):  
Parmod Verma ◽  
Ranbir Singh Rana ◽  
Ramesh Ramesh ◽  
Ranu Pathania

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.


Author(s):  
Vinícius Londe ◽  
Jaqueline Alves Pereira ◽  
Hildeberto Caldas de Sousa

Abstract Although important, phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics. Herein, we integrate phylogeny, ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches. We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park, Brazil, and related them to abiotic local factors. Contrary to our expectation, the phenophases of the congeneric species did not differ between habitats, but the reproductive phenophases of C. scabra did and was greater in drained soil. Phenophases of C. scabra were affected by the depth of the water table and maximum temperature in the wetland soil. Insolation, precipitation, maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil. The differences between C. scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits. On the other hand, the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution. This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions. Data of this nature are important in a changing world and can inform strategies for adaptive management.


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