scholarly journals POPULATION DENSITY OF SOME INSECT PESTS INFESTING GLOBE ARTICHOKE PLANTATIONS IN RELATION TO CERTAIN ECOLOGICAL FACTORS AT DAKAHALIA GOVERNORATE

2012 ◽  
Vol 3 (4) ◽  
pp. 347-353
Author(s):  
M. Taha ◽  
Horia Abd-el Wahab ◽  
Hanaa Mahmoud ◽  
Ghada Abd el hamed
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Ecological Factors ◽  
Globe Artichoke

scholarly journals BIOLOGI DAN TRANSFORMASI BELALANG KEMBARA LOCUSTA MIGRATORIA MANILENSIS MEYEN (ORTHOPTERA: ACRIDIDAE) PADA BEBERAPA TINGKAT KEPADATAN POPULASI DI LABORATORIUM

2005 ◽  
Vol 5 (1) ◽  
pp. 24-31
Author(s):  
Hamim Sudarsono ◽  
Rosma Hasibuan ◽  
Damayanti Buchori
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Control Strategies ◽  
Locusta Migratoria ◽  
Feeding Activity ◽  
Laboratory Population ◽  
Migratory Locust ◽  
Green House ◽  
Cage Size ◽  
Locusta Migratoria Manilensis

Biology and Transformation of the Migratory Locust Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) at Several Laboratory Population Density Levels.  The migratory locust, Locusta migratoria manilensis Meyen (Orthoptera: Acrididae) is one of insect pests in Indonesia that undergoes a unique polymorphic biology.  The locust develops a transformation phase which is triggered mainly by high population density.  Its recent outbreaks in several regions of Indonesia cause major concern and control strategies must be developed to strengthen control efforts in the future. Its unique polymorphic phenomenon, therefore, must be investigated thoroughly for the basis of management of the outbreak.  Due to its agility and its long range flying ability, the most realistic technique to study behavioral and morphological change of the locust is in controlled condition at a laboratory or a green house facility. The experiment was aimed to study effects of colony densities on the biology and transformation process of the migratory locust.  More specifically, the experiment was to study effects of population density on the feeding activity, mortality rate, and the ratio of F/C and E/F of the migratory locust L. migratoria manilensis.  The population densities were simulated in colonies at 2, 5, 10, 20, dan 30 couples per cage (cage size: 45x45x90 cm) reared in a green house. Results of the experiment show that, in general, higher densities of the migratory locust colonies tended to feed more rigorously than those of the less dense colonies.  The locust remained in solitary phase at the density of 2-5 couples per cage whereas the transient phase occured at the density of 10-20 couples per cage.  The colonies transformed to gregarious stage when their densities were 30 couples per cage or higher.  Mortality percentage tended to be higher at colonies with higher density, especially for the third instar of the migratory locust. 

scholarly journals Aedes albopictus (Skuse) susceptibility status to agrochemical-insecticides used in durian plantating systems in southern Thailand

2020 ◽  
Author(s):  
Sakda Ratisupakorn ◽  
Sokchan Lorn ◽  
Nsa Dada ◽  
Aran Ngampongsai ◽  
Pawit Chaivisit ◽  
...  
Keyword(s):  
Population Density ◽  
Aedes Albopictus ◽  
Insect Pests ◽  
Field Application ◽  
Insecticide Susceptibility ◽  
Future Studies ◽  
Lambda Cyhalothrin ◽  
Southern Thailand ◽  
Study Sites ◽  
Susceptibility Status

ABSTRACTHigh rates of dengue, chikungunya, and zika morbidity occur in southern Thailand. The intensive application of insecticides in orchards could impact not only agricultural insect pests, but also non-target insects, such as mosquitoes, or non-target beneficial insects. In this study, the population density and insecticide susceptibility of Aedes albopictus populations to field application concentrations of four agrochemical insecticides – cypermethrin, chlorpyrifos, carbaryl, and imidacloprid were examined. Mosquito eggs were collected from durian cultivation sites in five provinces in southern Thailand and hatched and allowed to develop to the adult stage. The study sites were categorized into three groups based on insecticide application; intensive-application of insecticides (IA), less-application of insecticides (LA), and no application of insecticides (NA). Twenty ovitraps were deployed for at least three consecutive days at each study site to collect mosquito eggs and to determine the Ae. albopictus population density then WHO tube assays being used to determine the susceptibility of adult mosquitoes to selected insecticides. This study represents the first report of the agrochemical insecticide susceptibility status of Ae. albopictus collected from durian orchards in southern Thailand. The study found that the populations of Ae. albopictus were susceptible to chlorpyrifos, but showed reduced mortality following exposure to lambda-cyhalothrin, carbaryl, and imidacloprid which is suggestive of the existence of resistance. These findings provide new insights into mosquito insecticide resistance focusing on Ae. albopictus populations and has important implications for mosquito and mosquito-borne disease control in Thailand as well as providing baseline data on which future studies can develop.

scholarly journals Effect of Silicon fertilization on two major insect pests of tomato under greenhouse conditions

2021 ◽  
Author(s):  
Aqeel Alyousuf ◽  
Dawood Hamid ◽  
Mohsen A. Desher ◽  
Amin Nikpay ◽  
Henk-Marten Laane
Keyword(s):  
Population Density ◽  
Insect Pests ◽  
Insect Pest ◽  
Tomato Leaf ◽  
Leaf Miner ◽  
Pest Species ◽  
Tomato Crop ◽  
Soil Drench ◽  
Tomato Leaf Miner ◽  
Acid Formulation

Abstract Tomato (Solanum lycopersicum L) is an important vegetable crop in Iraq. This horticultural crop is attacked by several insect pest species. Among them, the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and the tomato leaf miner Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) are the major threat of greenhouse tomatoes in Basrah province in south Iraq. The management of these pests is heavily based on application of chemical pesticides. Vast application of pesticides caused harmful damage to the environment, human health and may increasing the risk of pest resistance on insect populations. One of the promising strategies which are compatible with organic farming is application of silicon for enhancing plant vigor and resistance to pest damage on various agricultural crops. Due to these facts, the experiments have been carried out at Basrah University to evaluate the effects of silicon (Si) fertilization on tomato plants for reducing damage of these two major pests. Treatments comprised two type of Si applications (Soil drench treatment and foliar spraying) with four Si concentrations (0, 0.5, 1 and 2%) of AB Yellow ® silicic acid formulation. The population density of B. tabaci and T. absoluta were studied weekly during the growth season. The results clearly demonstrated that Silicon applications significantly decreased the population of immature of both whiteflies and tomato leaf miner on tomato crop in the greenhouse; Si-Foliar spraying was more effective in reducing the population density of these key pests compared to Si- soil drench application.

scholarly journals Species richness of thrips and whiteflies and their predators in mustard fields

2017 ◽  
Vol 15 (1) ◽  
pp. 7-14
Author(s):  
S Das ◽  
MM Rahman ◽  
MM Kamal ◽  
A Shishir
Keyword(s):  
Species Richness ◽  
Low Temperature ◽  
Significant Variation ◽  
Host Plants ◽  
Insect Pests ◽  
Ecological Factors ◽  
Effect Of Temperature ◽  
Predator Population ◽  
Population Abundance ◽  
Pest Population

With a view to assessing the effect of temperature (ºC) and locations on species richness of thrips and whiteflies and their natural enemies (NEs), predatory Geocoris bug and Asian lady bug beetle (LBB) in mustard field of BARI Sarisha 16, the experiment was carried out at the farmers’ fields in two specific locations of Southern Bangladesh, Rupsha, Khulna and Abhaynagar, Jessore during November, 2015 to March, 2016. The studies were laid out with randomized complete block deign (RCBD) maintaining four replicates. The results depicted that there was a significant variation in mean population abundance of thrips, whitefly and their predators across the observation dates, which principally resulted from the variation of temperature along the various observation dates in each location and between locations along with phenological characters of host plants. Initially, population of thrips and whitefly, and their predators were very low in both locations at first observation date of 20 November, 2015 which gradually colonized and reached the peak in 19 March, 2016 with temperature of 27.8°C and 71% RH in Khulna and 26.1ºC and 61% RH in Jessore. Notably, temperature ranging from 22–27°C during mid-February to March, 2016 considerably favors the species richness of both insect pests, thrips and whiteflies, and their predators, Geocoris bug and Asian lady bug beetle in both places. By contrast relative low temperature of 16–20°C from December 20, 2015 to January 29, 2016 affected the species richness of predators and pest as well. The yield of mustard, BARI Sarisha 16 was significantly higher in Jessore (1365.75 kgha–1) due to lower pest population and higher predator population relative to Khulna region (1277.25 kgha–1). Ecological factors especially temperature appeared as major striking factor of species richness and played crucial role in getting up and down of mustard insect pests and NEs population across various date of observations and between places.J. Bangladesh Agril. Univ. 15(1): 7-14, January 2017

Texcoco Region Archaeology

1975 ◽  
Vol 40 (2Part1) ◽  
pp. 227-230 ◽  
Author(s):  
Richard E. Blanton
Keyword(s):  
Population Density ◽  
Agricultural Land ◽  
General Pattern ◽  
Ecological Factors ◽  
The Political ◽  
Regional Centers

Charlton (1973) argues that Parsons' (1969, 1970) explanation for the abandonment of the central Texcoco region, Mexico, during the Early Toltec period, is misleading because Parsons considered only “non-ecological” factors. Specifically, Parsons suggested that this zone was not occupied because it was the boundary between the political spheres of two competing regional centers, Tula and Cholula. Charlton argues instead, that the region was abandoned due to “ecological” factors. Namely, he argues, the Early Toltec period was a period of low population density, when only the most suitable agricultural land was occupied; thus the central Texcoco region was not utilized because it is agriculturally marginal. Charlton’s emphasis on the use of “ecological” factors to explain the distribution of Early Toltec settlements is misleading because it does not allow prediction of the locations of other known Early Toltec settlements in the Valley of Mexico. Abandonment of large portions of the Valley of Mexico was a general pattern during this period, due to “Balkanization” and competition between local centers.

scholarly journals Impact of Some Ecological Factors on Fecal Contamination of Drinking Water by Diarrheagenic Antibiotic-ResistantEscherichia coliin Zagazig City, Egypt

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed Elsadek Fakhr ◽  
Maha Kamal Gohar ◽  
Amal Hassan Atta
Keyword(s):  
Drinking Water ◽  
Population Density ◽  
Distribution Systems ◽  
Virulence Genes ◽  
Fecal Contamination ◽  
Antibiotic Sensitivity ◽  
Ecological Factors ◽  
Antibiotic Resistant ◽  
Major Health Problem ◽  
E Coli

Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-ResistantEscherichia coliin Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated forE. coliexistence. Locations ofE. colipositive samples were investigated in relation to population density, water source, and type of water pipe. SixteenE. colistrains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems.

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