Laboratory Tests of Insecticides on Mosquito Larvae in Polluted and Tap Water

1963 ◽  
Vol 56 (6) ◽  
pp. 834-835
Author(s):  
Lawrence L. Lewallen ◽  
William H. Wilder
Keyword(s):  
Laboratory Tests ◽  
Tap Water ◽  
Mosquito Larvae

scholarly journals Different Hatching Rates of Floodwater Mosquitoes Aedes sticticus, Aedes rossicus and Aedes cinereus from Different Flooded Environments

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 279
Author(s):  
Anders Lindström ◽  
Disa Eklöf ◽  
Tobias Lilja
Keyword(s):  
Tap Water ◽  
Soil Samples ◽  
Mosquito Larvae ◽  
Retaining Structures ◽  
Retaining Structure ◽  
Large Numbers ◽  
Random Samples ◽  
Nuisance Species ◽  
Flooding Events ◽  
Hatching Rates

In the lower Dalälven region, floodwater mosquitoes cause recurring problems. The main nuisance species is Aedes (Ochlerotatus) sticticus, but large numbers of Aedes (Aedes) rossicus and Aedes (Aedes) cinereus also hatch during flooding events. To increase understanding of which environments in the area give rise to mosquito nuisance, soil samples were taken from 20 locations from four environmental categories: grazed meadows, mowed meadows, unkept open grassland areas and forest areas. In each location 20 soil samples were taken, 10 from random locations and 10 from moisture retaining structures, such as tussocks, shrubs, piles of leaves, logs, and roots. The soil samples were soaked with tap water in the lab, and mosquito larvae were collected and allowed to develop to adult mosquitoes for species identification. Fewer larvae hatched from mowed areas and more larvae hatched from moisture retaining structure samples than random samples. The results showed that Aedes cinereus mostly hatch from grazed and unkept areas and hatched as much from random samples as from structures, whereas Aedes sticticus and Aedes rossicus hatched from open unkept and forest areas and hatch significantly more from structure samples. When the moisture retaining structures in open unkept areas where Aedes sticticus hatched were identified it was clear that they hatched predominantly from willow shrubs that offered shade. The results suggest that Ae. sticticus and Ae. cinereus favor different flooded environments for oviposition.

Diving beetles (Dytiscidae) as predators of mosquito larvae (Culicidae) in field experiments and in laboratory tests of prey preference

2003 ◽  
Vol 93 (3) ◽  
pp. 219-226 ◽  
Author(s):  
E. Lundkvist ◽  
J. Landin ◽  
M. Jackson ◽  
C. Svensson
Keyword(s):  
Body Length ◽  
Negative Correlation ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Mosquito Larvae ◽  
Natural Control ◽  
Large Numbers ◽  
Diving Beetles ◽  
The Mean ◽  
Artificial Ponds

AbstractField experiments were performed in artificial ponds to evaluate how the density of predatory diving beetles (Dytiscidae) would affect the population levels of mosquito larvae (Culicidae). Mosquitoes colonizing the ponds were predominantly species of the genus Culex. In 2000, most of the dytiscids colonizing the ponds were small (Hydroporus spp.), and these predators had no impact on the size of larval mosquito populations, not even in ponds with added dytiscids. In 2001, larger beetles (Ilybius, Rhantus, and Agabus spp.) were more common, and there were significantly fewer mosquito larvae in ponds with the highest numbers of dytiscids. There was a negative correlation between numbers of diving beetles in the ponds and the mean body length of mosquito larvae. In neither year could dytiscid densities be maintained above a certain level owing to emigration. In laboratory tests, there were marked differences between three common dytiscid species in regard to preferences for Daphnia and Culex species as prey: Colymbetes paykulli Erichson chose mosquito larvae more often, whereas both Ilybius ater (De Geer) and I. fuliginosus (Fabricius) preferred Daphnia spp. All of the tested dytiscids consumed large numbers of prey. Since some dytiscid species can efficiently decrease populations of mosquito larvae, they are probably important in the natural control of these dipterans.

scholarly journals Disinfection of drinking and bathing water with oxyl

2002 ◽  
Vol 56 (2) ◽  
pp. 50-53
Author(s):  
Marjana Simonic
Keyword(s):  
Sodium Chloride ◽  
Electric Current ◽  
Laboratory Tests ◽  
Room Temperature ◽  
Tap Water ◽  
Treated Water ◽  
Bathing Water ◽  
Before And After ◽  
The Stability

An electrolysed solution of sodium chloride was examined for its disinfection potential in drinking and bathing water. The electrolysis of NaCl ((=1%) in tap water was performed at room temperature using a 10 A electric current in an electrolysis apparatus. Some laboratory tests were made, initially to determine the stability and efficiency of the disinfectant. Chemical and microbiological measurements of the treated water (according to DIN 19643 for bathing water) were then carried out before and after addition of the disinfectant agent.

Corrosion of Lead by Alternating Current

CORROSION ◽  
1964 ◽  
Vol 20 (5) ◽  
pp. 150t-157t ◽  
Author(s):  
C. E. GALIMBERTI
Keyword(s):  
Direct Current ◽  
Laboratory Tests ◽  
Current Flow ◽  
Tap Water ◽  
Alternating Current ◽  
Present Form ◽  
Current Leakage ◽  
Lead Compounds ◽  
Lead Electrodes ◽  
Current Rectification

Abstract From laboratory tests, it appears that corrosion of buried, lead-sheathed cables by alternating current is due to current leakage through breaks in the insulating coating. Even though the current flow in the lead sheathing may be small, it becomes concentrated, i.e., its density increases considerably at small openings through which the current is grounded into the soil. In tests in which direct current was superimposed on alternating current flowing to lead electrodes immersed in tap water, the corrosion of the electrode acting as anode was increased; corrosion of the cathode was decreased. Lead may also be cathodically protected by connecting it with a less noble metal, such as Fe, Zn or Mg. In the case of Mg, when connected so that it conducts the current rectification occurs which results in increased corrosion of the lead. The morphology of corrosion of lead by alternating current is characterized according to whether the anions present form soluble lead compounds (nitrate or acetate, for example) or insoluble products (sulfate or carbonate).

scholarly journals Impact if Chlorpyrifos on the Second Instar Mosquito Larvae as Bioindicator in El-Beheira Governorate, Egypt

2020 ◽  
Vol 1 (2) ◽  
pp. 1-11 ◽  
Author(s):  
Ebrahim E. Eissa ◽  
EH Radwan ◽  
N Abdel Hakeem ◽  
Abdel Aziz KK ◽  
HO Hashem ◽  
...  
Keyword(s):  
Water Pollution ◽  
Stream Water ◽  
Tap Water ◽  
Time Dependent ◽  
Mosquito Larvae ◽  
Organophosphate Insecticide ◽  
Culex Mosquito ◽  
Water Pollutants ◽  
Pollution Levels

Pesticides are the major source of concern as water pollutants. Chlorpyrifos (CPY) (O,O-diethyl-O-(3,5,6-trichloro-2-pyridinyl) phosphorothioate; CAS No. 2921-88-2). CPY is a widely used organophosphate insecticide. The aim of current study was to determine the effects of CPY on the second instar larvae of Culex mosquito as a bio-indicator of water pollution. Levels of CPY in stream water was evaluated. Toxicity of CPY was estimated on mosquito. Along with the evaluation of effects of water polluted with CPY on mosquito to predict the water pollution levels. Results showed that LC95 of CPY was 6331.30 mg/kg after 24hr and increased to 230506.4 ppm after 48hr of exposure. It was noted that the activity of CPY is concentration and time dependent. The 0.09 ppm concentration of CPY (the amount that was found in the stream water) had no effect on the second instar Culex larvae similar to the control (tap water). There is no effect after 72,96h of exposure of the population to the detected insecticide. It could be concluded that mosquito is not a bioindicator of CPY pollution at the detected level in stream water.

scholarly journals Hubungan Jumlah dan Kepadatan Penghuni Rumah serta Keberadaan Nyamuk dengan Frekuensi Menggigit Nyamuk Aedes aegypti Saat Mencari Darah di Kabupaten Cirebon Provinsi Jawa Barat

2010 ◽  
Vol 2 (2) ◽  
pp. 95-98
Author(s):  
Lukman Hakim ◽  
Asep Jajang Kusnandar
Keyword(s):  
Infectious Disease ◽  
Risk Factor ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Dengue Hemorrhagic Fever ◽  
Laboratory Tests ◽  
Hemorrhagic Fever ◽  
Mosquito Larvae ◽  
Residential Settings ◽  
Dengue Transmission

Dengue hemorrhagic fever (DHF) is an infectious disease caused by dengue virus with the widest spread in the Asian region. In Indonesia, every year is always an outbreak in some provinces, the largest occurred in 1998 and 2004 with the number of patient mortality by 79 480 people with 800 people. To know the risk factor for dengue transmission in Cirebon District that had a high DHF cases, had been conducted the research with calculating the number and density of humans at the houses and also survey of density of Aedes aegypti pre-adult and adult stages.The research was resulting that the house index (HI) of Ae. aegypti is 58%, while homes found Ae. aegypti adults is 46%, 6 of which house is the house that is not found larvae / pupae of mosquitoes. The laboratory tests found that the frequency of biting Ae. aegypti mosquitoes average 4.5 times per day, at least 2 times and no more than 7 times per day. Number of people bitten by adult mosquitoes average of 3.1 people per day, is at least 2 people and maximum 5 people per day. Based on the statistically test, it is known that there is significant correlation between the number of inhabitants of the house and the presence of mosquito larvae / pupa of Ae. aegypti mosquito with biting frequency, whereas the most dominant variable was the presence of larvae / pupae of mosquitoes. Furthermore, it is advisable to do the cleaning intensification of Aedes breeding places inand outside the home including those hidden. It is also necessary to place residential settings so that the number of occupants per house so less.

scholarly journals Coagulation-Flocculation: A potential Application for Mosquito Larval Source Management (LSM) with No Insecticide Resistance

2020 ◽  
Author(s):  
XinRan Li ◽  
Minsheng Huang ◽  
PeiEn Leng ◽  
XinYu Lu ◽  
Bing Xiao
Keyword(s):  
Insecticide Resistance ◽  
Culex Pipiens ◽  
Control Method ◽  
Mosquito Control ◽  
Tap Water ◽  
Oviposition Preference ◽  
Mosquito Larvae ◽  
Culex Pipiens Pallens ◽  
Lethal Time ◽  
Pipiens Pallens

Abstract Background: Mosquito control is an essential step to eliminate mosquito-borne diseases. Larval mosquitoes have a more limited home range and lower resistance to adverse environment than adults, thus can be ideal targets for vector control in some cases. Coagulation-flocculation technology, which could be used for water treatment in breeding sites of several vector mosquito species, can significantly change both the distribution of organic particles and surface sediment characteristics in water environment. The aim of this study was to explore the effect, principle and possibility of using coagulation-flocculation technology in immature mosquitoes killing.Method: In laboratory, chlorine-free tap water was treated with Poly Aluminum Chloride (PACl, sewage treatment using). The oviposition preference of gravid Culex pipiens pallens, the hatching of mosquito eggs and the survival amount of mosquito larvae were observed, and the pupa amounts were recorded each day.Results: Coagulation-flocculation treatment could improve the oviposition preference of Culex pipiens pallens to some extent (compared with ordinary chlorine-free tap water), but not significantly (p=0.345). After treatment, mosquitoes laid eggs in chlorine-free tap water were 31.88% more than those laid in untreated water. Coagulation-flocculation affected the larvae’s survival by physical means: Ⅰ) alum floc layer increases the difficulty of larvae foraging, leads larvae starving to death; (Ⅱ) the little floc particles adhere to the surface of larvae, which stops larvae from floating upward to breathe. As a result, the alum floc layer had a good killing effect on the mosquito larvae, presented the half lethal time (LT50) of 2d, the 90% lethal time (LT90) of 8.7±7.3 ~ 14±4.5 d, and the pupation rate of 0 ~ (6.5±0.5)%, respectively.Conclusions: PACl coagulation-flocculation produced lots of alum flocs, which may attract more gravid mosquitoes for laying eggs, and was shown to be highly active against 1st~2nd instar larvae. The principle of this technology illustrates this method won’t develop insecticide resistance. In this study, coagulation-flocculation technology is considered to be a new potential approach to a sustainable, low-impact and low-cost mosquito control method.

Critical limb ischaemia in diabetes: definition, assessment, prognosis

VASA ◽  
2001 ◽  
Vol 30 (Supplement 58) ◽  
pp. 21-27
Author(s):  
Luther
Keyword(s):  
Diabetic Foot ◽  
Laboratory Tests ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Clinical Use ◽  
Arterial Reconstruction ◽  
Arterial Circulation ◽  
Diabetic Foot Disease ◽  
Foot Disease ◽  
Fontaine Classification

In diabetic foot disease, critical limb ischaemia (CLI) cannot be precisely described using established definitions. For clinical use, the Fontaine classification complemented with any objective verification of a reduced arterial circulation is sufficient for decision making. For scientific purposes, objective measurement criteria should be reported. Assessment of CLI should rely on the physical examination of the limb arteries, complemented by laboratory tests like the shape of the PVR curve at ankle or toe levels, and arteriography. The prognosis of CLI in diabetic foot disease depends on the success of arterial reconstruction. The best prognosis for the patients is with a preserved limb. Reconstructive surgery is the best choice for the majority of patients.

The Reliability of Retrieval-Induced Forgetting

2012 ◽  
Vol 17 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Rosalind Potts ◽  
Robin Law ◽  
John F. Golding ◽  
David Groome
Keyword(s):  
Individual Differences ◽  
Recognition Test ◽  
Laboratory Tests ◽  
The Other ◽  
Clinical Factors ◽  
Test Items ◽  
T1 And T2 ◽  
Test Materials ◽  
Induced Forgetting

Retrieval-induced forgetting (RIF) refers to the finding that the retrieval of an item from memory impairs the retrieval of related items. The extent to which this impairment is found in laboratory tests varies between individuals, and recent studies have reported an association between individual differences in the strength of the RIF effect and other cognitive and clinical factors. The present study investigated the reliability of these individual differences in the RIF effect. A RIF task was administered to the same individuals on two occasions (sessions T1 and T2), one week apart. For Experiments 1 and 2 the final retrieval test at each session made use of a category-cue procedure, whereas Experiment 3 employed category-plus-letter cues, and Experiment 4 used a recognition test. In Experiment 2 the same test items that were studied, practiced, and tested at T1 were also studied, practiced, and tested at T2, but for the remaining three experiments two different item sets were used at T1 and T2. A significant RIF effect was found in all four experiments. A significant correlation was found between RIF scores at T1 and T2 in Experiment 2, but for the other three experiments the correlations between RIF scores at T1 and T2 failed to reach significance. This study therefore failed to find clear evidence for reliable individual differences in RIF performance, except where the same test materials were used for both test sessions. These findings have important implications for studies involving individual differences in RIF performance.

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