The Susceptibility of various Species of Mosquitos to DDT, Dieldrin and BHC

1955 ◽  
Vol 46 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R. H. Wharton
Keyword(s):  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Lethal Concentration ◽  
Median Lethal Concentration ◽  
Adult Females ◽  
Anopheles Maculipennis ◽  
Culex Pipiens Molestus ◽  
Filter Papers

The susceptibility of various mosquitos to DDT, dieldrin and BHC has been studied. Adult females were exposed in small tubes lined with filter papers impregnated with insecticide-oil solutions. Larvae were exposed to insecticideacetone suspensions in water.Adult mosquitos tested in London showed no striking differences in susceptibility to DDT, though the median lethal concentration (MLC) of Culex pipiens molestus Forsk. (1·6 per cent.) was greater than the MLC of Aëdes aegypti (L.) (0·9), Anopheles maculipennis var. atroparvusvan Thiel (1·0), or A. quadrimaculatus Say (·7). C. p. molestus and Aë. aegypti showed the same order of susceptibility to dieldrin and BHC, with Anopheles m. atroparvus more susceptible to both insecticides.

On Water-finding and Oviposition by captive Mosquitoes

1942 ◽  
Vol 32 (4) ◽  
pp. 279-301 ◽  
Author(s):  
John S. Kennedy
Keyword(s):  
Aedes Aegypti ◽  
Water Vapour ◽  
Culex Pipiens ◽  
Water Surface ◽  
Short Range ◽  
Diurnal Changes ◽  
Hovering Flight ◽  
Surface Contact ◽  
Culex Pipiens Molestus ◽  
Geotactic Response

1. The behaviour of Anopheles labranchiae atroparvus, Culex pipiens molestus and Aëdes aegypti has been studied before and during oviposition.2. Anopheles and Culex when ready to lay make repeated descents to the ground and fly about with a skimming-hopping movement, while Aëdes flies about generally, at all heights.3. On encountering water Anopheles breaks into a hovering flight, laying its eggs during this “oviposition dance” or while settled on the water. Culex stops “dead” on the water and lays its eggs settled there, as does Aëdes but with some fidgeting about. After encountering water mosquitoes may leave it again, but fly about the floor more steadily and persistently than before.4. Among the factors which stimulate mosquitoes after they have arrived directly over a water surface, contact with the surface is essential for actual oviposition by Culex and Aëdes, and almost so for Anopheles. Good pre-ovipository responses may be induced by water vapour alone and by the reflection from the surface, although how this latter stimulus acts is not clear. A dark appearance, especially if the surroundings are relatively light, facilitates these responses.5. Direct attraction of the mosquitoes over the short range available in a cage was only induced by a contrastingly dark appearance, but Anopheles and Culex are aided in water finding by diurnal changes, correlated with light and activity changes, in the sense of their geotactic response.

Estudio y evaluación de depredadores y bacterias entomopatógenas de Aedes aegypti (L.) y Culex pipiens (L.), como potenciales agentes de control

2010 ◽  
Author(s):  
◽  
María Cecilia Tranchida
Keyword(s):  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Principal Vector ◽  
La Plata

Aedes aegypti y Culex pipiens se encuentran entre las principales especies de mosquitos vectores de enfermedades a nivel mundial. Ambas, son de gran importancia sanitaria en la Argentina. Aedes aegypti, es el principal vector del dengue y la fiebre amarilla. Está presente en la Argentina desde 1983, cuando fue confirmada su reemergencia en nuestro país. A partir de entonces comenzaron a detectarse casos de dengue hasta que el último brote de esta enfermedad en 2009 produjo 24.720 casos autóctonos confirmados por la OPS a nivel nacional. Culex pipiens es vector de algunas filariasis, y de importantes arbovirosis como la ocasionada por el virus del Nilo Occidental. La actividad vectorial de este mosquito se ve incrementada en zonas donde la densidad de zanjas de desagüe domiciliario es elevada, ya que este tipo de ambiente constituye un lugar propicio para su desarrollo. De su importancia sanitaria nace la necesidad de controlar su actividad vectorial, manteniendo las poblaciones en bajas densidades. El objetivo de este trabajo fue desarrollar estrategias para el control de A. aegypti y C. pipiens, basadas en métodos biológicos, eficaces, permanentes y seguros para el ambiente, mediante el empleo de enemigos naturales presentes en las poblaciones de ambas especies. En este trabajo, fueron evaluados copépodos, turbelarios y peces como depredadores; y bacterias entomopatógenas (α-protobacterias y bacterias esporulantes). El estudio de los copépodos, tuvo como objetivo identificar a la comunidad de copépodos larvívoros que se desarrolla en los criaderos de mosquitos, ubicados en los alrededores de la ciudad de La Plata, para identificar nuevas especies capaces de depredar mosquitos que habitan recipientes artificiales (A. aegypti y C. pipiens). La diversidad de copépodos larvívoros fue mayor en los cuerpos de agua permanentes. Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus y Mesocyclops longisetus fueron seleccionados por su capacidad depredadora. En el laboratorio fueron evaluadas: la capacidad de depredación de ambos sexos y diferentes estadios, preferencia de especie presa, y la tasa de depredación diaria. Las hembras de estas especies de copépodos presentaron mayor capacidad depredadora. No se detectó preferencia de los copépodos hacia ninguna de las especies de mosquitos. También se evaluó la tolerancia a la desecación y la capacidad de vivir en el agua que se acumula en los recipientes artificiales. Diacyclops uruguayensis y A. robustus sobrevivieron en las condiciones de sequía ensayadas en este estudio, pero D. uruguayensis mostró una menor supervivencia en el agua de recipientes artificiales. Macrocyclops albidus no sobrevivió en condiciones de sequía ni toleró el agua extraída de los recipientes artificiales. La supervivencia de M. longisetus ante estas condiciones, fue reducida. Se concluyó que las especies D. uruguayensis y A. robustus podrían ser buenos candidatos para el control de especies de mosquitos que crían en recipientes artificiales.

Acute toxicity and accumulation of microcystin-leucine-arginine in the crayfish Procambarus clarkii (Girard, 1852)

Crustaceana ◽  
2015 ◽  
Vol 88 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Zhenhua An ◽  
Zhenhua An ◽  
Longsheng Sun ◽  
Zhenhua An ◽  
Longsheng Sun ◽  
...  
Keyword(s):  
Survival Rate ◽  
Acute Toxicity ◽  
Procambarus Clarkii ◽  
Abdominal Muscle ◽  
Water Bodies ◽  
Lethal Concentration ◽  
Median Lethal Concentration ◽  
Toxicity Effect ◽  
Cyanobacteria Blooms

The aim of this study was to determine the acute toxicity effect and the accumulation of microcystin-leucine-arginine (MC-LR) on the crayfish Procambarus clarkii (Girard, 1852). Juvenile P. clarkii (5.47 ± 1.3 g) were cultured under 5 different MC-LR concentrations (0.3, 0.6, 1.2, 2.4, 4.8 mg/l), then the acute toxicity effect was observed. The median lethal concentration (LC50) of MC-LR on juvenile P. clarkii was 3.741 mg/l at 24 h, 1.494 mg/l at 48 h, 0.817 mg/l at 72 h and 0.567 mg/l at 96 h. Accumulation of MC-LR was measured in different organs of mature P. clarkii (58.7 ± 3.8 g) exposed to 0.3 mg/l MC-LR for 120 h. The detected MC-LR concentration decreased in the sequence: hepatopancreas > ovary > abdominal muscle > intestine. Hepatopancreas and ovary were found to be the main targets of the toxin. The results suggested that the MC-LR produced by cyanobacteria blooms could not only reduce the survival rate of juvenile P. clarkii but also affect the fecundity of mature crayfish. This research also provides a reference basis for the detection and assessment of the pollution of water bodies in P. clarkii culture.

scholarly journals Cloning and Expression of Two Crystal Protein Genes, cry30Ba1 and cry44Aa1, Obtained from a Highly Mosquitocidal Strain, Bacillus thuringiensis subsp. entomocidus INA288

2006 ◽  
Vol 72 (8) ◽  
pp. 5673-5676 ◽  
Author(s):  
Takeshi Ito ◽  
Tomonori Ikeya ◽  
Ken Sahara ◽  
Hisanori Bando ◽  
Shin-ichiro Asano
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Crystal Protein ◽  
Cloning And Expression ◽  
Culex Pipiens Pallens ◽  
Bacillus Thuringiensis Subsp ◽  
Pipiens Pallens ◽  
Crystal Protein Genes

ABSTRACT Two novel crystal protein genes, cry30Ba and cry44Aa, were cloned from Bacillus thuringiensis subsp. entomocidus INA288 and expressed in an acrystalliferous strain. Cry44Aa crystals were highly toxic to second-instar Culex pipiens pallens (50% mortality concentration [LC50] = 6 ng/ml) and Aedes aegypti (LC50 = 12 ng/ml); however, Cry30Ba crystals were not toxic.

scholarly journals Fumigant toxicity of some essential oils against Red Flour Beetles, Tribolium castaneum (Herbst) and its safety to mammals

2020 ◽  
Vol 80 (4) ◽  
pp. 769-776
Author(s):  
T. M. Sileem ◽  
A. L. Mehany ◽  
R. S. Hassan
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Tribolium Castaneum ◽  
Larval Stage ◽  
Adult Stage ◽  
Lethal Concentration ◽  
Median Lethal Concentration ◽  
Histological Changes ◽  
Garlic Oil ◽  
Garlic Essential Oil

Abstract Fumigant activities for three essential oils; Garlic oil (Allium sativum L); Chili pepper (Capsicum annuum L.) and Nigella (Nigella sativa L.) were assessed at different concentrations against the adult and 20-days old larval stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in the laboratory. The accumulative mortality was observed at different exposure periods (3, 5 and 7 days). The residual effect of garlic oil that was the effective oil, on the treated wheat grains was evaluated with respect to histological changes in the liver, kidney, and stomach of rat fed on this treated wheat. The results showed that the mortality rates of treated stages increased with increasing the time of fumigation treatment. Moreover the highest essential oils toxicity at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (126, 53, and 47 mg/L air) for adult stage and were (79, 62, and 41 mg/L air) for larval stage, respectively in the case of Garlic oil treatment. While, the lowest essential oils effective was Nigella oil at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (3594, 629, and 335 mg/L air) for adult stage and were (1040, 416, and 227 mg/L air) for larval stage, respectively. The toxicity effect of various essential oils against adults and larvae of T. castaneum at the LC50at 7 days fumigation could be arranged in descending order as follows: Garlic oil, Chili pepper oil, and Nigella oil. The histological changes showed that the organs slightly affected at the fumigation for 3 days. It may be concluded that the garlic essential oil is the good effective fumigant to control T. castaneum in the stored products and it recommended that the fumigation period does not exceed 3 days. The garlic essential oil has the potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity and its safety.

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