scholarly journals Population dynamics of exotic rugose spiralling whitefly, Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) on coconut as influenced by weather factors and natural enemies

2020 ◽  
pp. 120-125
Author(s):  
K. Elango ◽  
S. Jeyarajan Nelson
Keyword(s):  
Population Dynamics ◽  
Negative Correlation ◽  
Natural Enemies ◽  
Tamil Nadu ◽  
Abiotic Factors ◽  
Climatic Conditions ◽  
Weekly Interval ◽  
Maximum Temperature ◽  
Weather Factors ◽  
Extent Of Damage

The rugose spiralling whitefly, Aleurodicus rugioperculatus Martin is a new exotic pest occurring in several crops including coconut since 2016 in India. Due to variation in the agro-climatic conditions of different regions, arthropods show varying trends in their incidence also in nature and extent of damage to the crop. Besides, abiotic factors also play a key role in determining the incidence and dominance of a particular pest and their natural enemies in a crop ecosystem. The population dynamics of new exotic whitefly species, A. rugioperculatus and their associated natural enemies was assessed on five-year-old Chowghat Orange Dwarf coconut trees at Coconut Farm of Tamil Nadu Agricultural University. The study indicated that RSW was found throughout the year on coconut and the observation recorded on weekly interval basis shows that A. rugioperculatus population escalated from the first week of July 2018 (130.8 nymphs/leaf/frond) reaching the maximum during the first week of October (161.0 nymphs/leaf/frond) which subsequently dwindled to a minimum during April. The parasitisation by E. guadeloupae on RSW ranged from 31.60 percent in Aug. 2018 to 57.60 percent in December 2018. The association of biotic and abiotic factors with A. rugioperculatus population showed a negative correlation with E. guadeloupae and C. montrouzieri. There was a significant positive correlation between maximum temperature and minimum temperature as well as relative humidity. However, rainfall showed a negative correlation with A. rugioperculatus population.

scholarly journals Incidence forecasting of new invasive pest of coconut rugose spiraling whitefly (Aleurodicus rugioperculatus) in India using ARIMAX analysis

2021 ◽  
Vol 23 (2) ◽  
pp. 194-199
Author(s):  
K.ELANGO ◽  
S. JEYARAJAN NELSON ◽  
P.DINESHKUMAR
Keyword(s):  
Tamil Nadu ◽  
Prediction Models ◽  
Time Series Data ◽  
Management Strategies ◽  
Climatic Conditions ◽  
Invasive Pest ◽  
Series Data ◽  
Maximum Temperature ◽  
Weather Factors ◽  
Extent Of Damage

The rugose spiraling whitefly (RSW), Aleurodicus rugioperculatus Martin is a new invasive pest occurring in several crops including coconut since 2016 in India from Tamil Nadu, Karnataka, Kerala and Andhra Pradesh. The population dynamics of new invasive whitefly species, A. rugioperculatus study indicated that RSW was found throughout the year on coconut and the observation recorded on weekly interval basis shows that A. rugioperculatus population escalated from the first week of July 2018 (130.8 nymph/ leaf/ frond) reaching the maximum during the first week of October (161.0 nymph/ leaf/ frond) which subsequently dwindled to a minimum during April. Due to variation in the agro-climatic conditions of different regions, arthropods show varying trends in their incidence also in nature and extent of damage to the crop. Influence of weather parameters on rugose spiralling whitefly incidence is lacking, which is essential for developing management strategies. The forecasting model to predict rugose spiralling whitefly incidence in coconut was developed by ARIMAX model of weekly cases and weather factors. In exploring different prediction models by fitting covariates to the time series data, ARIMA (0,2,1) with Maximum temperature was found best model for predicting the rugose  spiralling whitefly incidence and all covariates were found non-significant predictors except maximum temperature.

scholarly journals Influence of Abiotic Factors on Population of Aphid Complex and Its Coexisting Natural Enemies in Mustard Agroecosystem

2021 ◽  
pp. 150-154
Author(s):  
Somala Karthik ◽  
U. Mukherjee
Keyword(s):  
Relative Humidity ◽  
Negative Correlation ◽  
Natural Enemies ◽  
Abiotic Factors ◽  
Maximum Temperature ◽  
Peak Activity ◽  
Rabi Season ◽  
Mustard Aphid ◽  
Positive Correlation ◽  
Syrphid Larvae

A field experiment was conducted to determine the population build-up of mustard aphid and their natural enemies in relation to abiotic factors at TCA, Dholi during the Rabi season of 2018-19 and 2019-20 respectively. The incidence of mustard aphid started in the 2nd and 3rd SMW of 2019 and 2020 respectively and reached maximum in 8th SMW in both the years. However, the predatory activity of coccinellids, syrphid larvae and spiders were started from 3rd SW with their peak activity at 3rd and 4th week of February in both the years. Mustard aphid population exhibited positive correlation with maximum temperature (0.347 & 0.543), minimum temperature (0.317 & 0.152) and negative correlation with relative humidity (-0.083 & -0.479) during 2019 & 2020 respectively and rainfall (-0.35) during 2020. However, natural enemies viz., coccinellids, syrphid larvae and spiders exhibited positive correlation with Tmax, Tmin, rainfall and negative correlation with RH in both the years.

scholarly journals The Dominance of physico-morphic plant traits in regulating population density of Bemisia tabaci and Thrips tabaci in Bt and non-Bt Cotton

1970 ◽  
pp. 28-32
Author(s):  
Mirza Abdul Qayyum, Muhammad Asad Saleem, Muhammad Ishtiaq ◽  
Ghulam Murtaza, Saif Ullah, Aboubakar Siddique
Keyword(s):  
Bemisia Tabaci ◽  
Negative Correlation ◽  
Plant Traits ◽  
Insect Pests ◽  
Research Area ◽  
Climatic Conditions ◽  
Thrips Tabaci ◽  
Maximum Temperature ◽  
Bt Cotton ◽  
Weather Factors

Policy makers, journalists and other commentators often advocate transgenic cotton (Gossypium spp.) as poor-performer against sucking insects that pose a great threat to production targets. A field study was carried out for seasonal occurrence of whitefly (Bemisia tabaci Gennadius) and thrips (Thrips tabaci Lindeman) on two of cotton genotypes namely Bt MNH-992 and non-Bt Cyto-124 under climatic conditions of Multan, Pakistan from July-October, 2017. Impact of environment as a factor was hypothesized on pests on two experimental sites [Research Area (RA) & Farmer Field (FF)]. Maximum population of whitefly at RA (13.5 and 16.7 individuals per plant) for Bt and non-Bt, respectively was recorded during SMW 40, while correspondent minimum populations (0.6 & 1.2 individuals per plant) was found during SMW28 in RA. The peak population of thrips was observed at RA during 30th SMW as (4.9 & 8.9 individuals per plant), respectively at Bt and non-Bt genotypes, declined to the lowest level of (0.1 & 0.3 individuals) in 41st SMW for both genotypes. Bt-cotton harbored relatively lower population of B. tabaci and T. tabaci in both fields owning to the presence of physico-morphich plant characters. A negative correlation of B. tabaci population was found with a maximum temperature and rainfall, and a positive relation with humidity. T. tabaci had a positive correlation with temperature and rainfall, and a negative correlation with relative humidity. The current research concluded that weather factors play and important role to increase or decrease the populations of sucking insect pests of cotton.

Population dynamics of aphid, Myzus persicae (Sulzer)(Hemiptera: Aphididae) on different Brassica species

2017 ◽  
Author(s):  
Joni Kumar ◽  
Bishwajeet Paul
Keyword(s):  
Population Dynamics ◽  
Abiotic Factors ◽  
Correlation Coefficients ◽  
Brassica Species ◽  
Significant Negative Correlation ◽  
Aphid Population ◽  
Maximum Temperature ◽  
Rabi Season ◽  
Rapid Multiplication ◽  
Weather Parameters

Present studies deal with continuous observation of aphid population on different brassica species at every fourteen days interval. Five plants were selected randomly from each plot. The top 10cm terminal portion was used for counting of aphid population. The first appearance of aphid population was found at end of December in Brassica rapa var toria, B. rapa var yellow sarson and Brassica juncea. The correlation coefficients between aphid population and abiotic factors revealed contradictory results. Except for a few instances the abiotic parameters show a low order of association with aphid population. A significant negative correlation of aphid population was found with maximum temperature in B. rapa var toria (r= -0.963**), B. rapa var yellow sarson (r= -0.877*) and B. juncea (r= -0.913*). The population dynamics study of coccinellid beetles revealed that its population increased gradually with the increase of aphid population and vice-versa. In our experiment none of the weather parameters alone was responsible for the multiplication and growth of the aphid but it is assumed that during major part of rabi season, the meteorological parameters remained conducive for the rapid multiplication of aphid.

scholarly journals Influence of weather factors on the abundance and population dynamics of Spodoptera litura F. and Pieris brassicae L. on cabbage

2017 ◽  
Vol 15 (1) ◽  
pp. 13-21
Author(s):  
MMH Khan ◽  
S Talukder
Keyword(s):  
Population Dynamics ◽  
Relative Humidity ◽  
Negative Correlation ◽  
Spodoptera Litura ◽  
Pieris Brassicae ◽  
Strong Positive Correlation ◽  
Weather Factors ◽  
Larval Population ◽  
Strong Negative Correlation ◽  
Minimum Relative Humidity

In order to study the influence of weather factors on the abundance and population dynamics of Spodoptera litura F. and Pieris brassicae L. on cabbage, a field experiment was conducted. Larval population of S. litura ranged from 0.56 to 1.57 larvae/plant during 8 January to 12 February 2014 crop season while the highest peak was on 5 February 2014 (1.57 larvae/plant) at 29.5 0C temperature. In case of Pieris brassicae, larval population ranged from 0.58 to1.98 larvae/plant and the highest peak of P. brassicae was also on 5 February. The highest peak was on 5 February 2014 at 96% and 38% relative humidity of both maximum and minimum categories and the highest peak of P. brassicae was on 5 February. There was a strong positive correlation (r = 0.824 and r = 0.920) between population of Spodoptera litura and temperature (maximum and minimum). On the other hand, there was a negative correlation (r = -0.439) between population of S. litura and maximum relative humidity and a strong negative correlation (r = - 0.716) between population of S. litura and minimum relative humidity. The population of Pieris brassicae was positively correlated (r = 0.899 and r = 0.956) with maximum and minimum temperatures. There was a negative correlation (r = -0.443) between population of P. brassicae and maximum relative humidity and a strong negative correlation (r = - 0.645) between population of P. brassicae and minimum relative humidity.SAARC J. Agri., 15(1): 13-21 (2017)

scholarly journals Spatial Analysis and Population Dynamics of Haplaxius crudus (Hemiptera: Cixiidae) in Coconut Amazon

2019 ◽  
Vol 11 (14) ◽  
pp. 186 ◽  
Author(s):  
Lucas Faro Bastos ◽  
Artur Vinícius Ferreira dos Santos ◽  
Fernanda Valente Penner ◽  
Lizandra Maria Maciel Siqueira ◽  
Anderson Gonçalves da Silva ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Spatial Distribution ◽  
Climatic Factors ◽  
Abiotic Factors ◽  
Spherical Model ◽  
Climatic Conditions ◽  
Brachiaria Humidicola ◽  
Lethal Yellowing ◽  
American Palm ◽  
Primary Vector

Haplaxius crudus is the primary vector of the phytoplasma that causes the Lethal Yellowing of Coconut, a disease that has become a barrier to the establishment of large coconut plantations in the world. The objective of this study was to determine the spatial distribution pattern and population dynamics of H. crudus adults by correlating them with the abiotic factors, such as temperature and rainfall in commercial dwarf coconut palm plantations. Collection of American palm cixiid was carried out using yellow sticky traps fixed to the abaxial part of the coconut leaves. The sampled plants were georeferenced to obtain the geographic coordinates and geostatistical analysis, besides the planialtimetric survey of the experimental plot for the preparation of the map that shows the topographic conformation of the terrain. Insects were found at the study site throughout the year, showing greater abundance in months when the average monthly temperatures and rainfall were not significant. The climatic factors showed a correlation with the total of insects, positive for the temperature, with 0.733 and negative for the precipitation with -0.606. The spatial distribution of H. crudus displayed an aggregate pattern, explained by the spherical model. The infestation focus occurred in the periphery of the plot, near a Brachiaria humidicola pasture. It was concluded that the infestation of the H. crudus showed a behavior directly related to the local climatic conditions and the aggregate spatial distribution explained by the spherical model, therefore, forming shrubs with a radius of 154 to 190 m, with areas of influence between 7.45 and 17.80 ha, which coincide with the lower part of the terrain.

scholarly journals Population dynamics of natural enemies on bt / non bt cotton and their correlation with weather parameters

2017 ◽  
Vol 9 (4) ◽  
pp. 2360-2365 ◽  
Author(s):  
Roomi Rawal ◽  
K. K. Dahiya ◽  
Roshan Lal ◽  
Adesh Kumar
Keyword(s):  
Population Dynamics ◽  
Natural Enemies ◽  
Maximum Temperature ◽  
Adult Plant ◽  
Bt Cotton ◽  
Crop Season ◽  
Cotton Genotypes ◽  
Weather Parameters ◽  
Two Peaks ◽  
Cotton Cultivar

The field study was carried out at Research Farm of cotton section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, India to determine the effect of environmental factors and seven cotton genotypes (Bt and non Bt) on three natural enemies namely chrysoperla, coccinellids beetle and spi-ders. Natural enemies remained active throughout the crop season (with two peaks) with little differences among them. Chrysoperla and coccinellids both were remained active from 25th to 40th SMW (June to October, 2014) while spiders were active from 25th to 41st. It was observed that highest population of Chrysoperla (1.17 eggs/plant) and spiders (1.59 adult/plant) was observed on Bt cotton cultivar namely RCH-134 and JK-1947 respectively. However, coccinellids preferred non Bt genotype (HHH-223) for their population build-up. Chrysoperla and coccinellids popula-tion was significantly negatively correlated with maximum temperature (r = -0.527 at 5% and r = -0.626 at 1% re-spectively); positively correlated with RHm, RHe; negatively correlated with minimum temperature and wind speed without significance. While, spiders population showed negative correlation with all weather parameters except sun-shine hours. It was observed that population of the natural enemies fluctuated under different environmental conditions during cotton season.

scholarly journals NATURAL ENEMIES OF HERBIVORES MAINTAIN THEIR BIOLOGICAL CONTROL POTENTIAL UNDER FUTURE CO2, TEMPERATURE AND PRECIPITATION PATTERNS

2020 ◽  
Author(s):  
Cong Van Doan ◽  
Marc Pfander ◽  
Anouk Guyer ◽  
Xi Zhang ◽  
Corina Maurer ◽  
...  
Keyword(s):  
Natural Enemies ◽  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Abiotic Factors ◽  
Parasitoid Wasp ◽  
Wolf Spider ◽  
Climatic Conditions ◽  
Insect Herbivores ◽  
Temperature And Precipitation ◽  
Increased Temperature

ABSTRACTClimate change will profoundly alter the physiology and ecology of plants, insect herbivores and their natural enemies, resulting in strong effects on multitrophic interactions. Yet, manipulative studies that investigate the direct combined impacts of changes in CO2, temperature, and precipitation on this group of organisms remain rare. Here, we assessed how three day exposure to elevated CO2, increased temperature, and decreased precipitation affect the performance and predation success on species from four major groups of natural enemies of insect herbivores: an entomopathogenic nematode, a wolf spider, a ladybug and a parasitoid wasp. Future climatic conditions (RCP 8.5), entailing a 28% decrease in precipitation, a 3.4°C raise in temperature and a 400 ppm increase in CO2 levels, slightly reduced the survival of entomopathogenic nematodes, but had no effect on the survival of other species. Predation success was not negatively affected in any of the tested species, but was even increased for wolf spiders and entomopathogenic nematodes. Factorial manipulation of climate variables revealed a positive effect of reduced soil moisture on nematode infectivity, but not of increased temperature or elevated CO2. These results suggest that natural enemies of herbivores are well adapted to short term changes in climatic conditions and may not suffer from direct negative effects of future climates. These findings provide mechanistic insights that will inform future efforts to disentangle the complex interplay of biotic and abiotic factors that drive climate-dependent changes in multitrophic interaction networks.

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