Interaction between bacterial and chemical larvicides used in mosquito control

The bacterial larvicdis "Bacillus thuringiensis H-14 and Bacillus sphaericus 15934" were biologically assayed against the 3rd instar Culex pipiens larvicide, with each other or with the conventional chemical larvicide "dieldrin". A results indicated that the larval mortality occurred when these larnicides were used simultaneously or in sequences, were found to be higher than that achieved when these preparations were used separately. So it may be assumed that, it is preferable to use these bacterial larnicides in integration with the chemical one in mosquito larval control programmes, instead of using each of them alone

Experimental transmission of wuchereria bancrofti by culex pipiens using capillary feeding technique

A capillary feeding technique was developed to provide an easy rapid method to asses L3 larvae transmission by infected Cx. pipiens under laboratory conditions. By using this technique, the infective females of Cx. pipiens to W. bancrofti infection could be separated into two groups Transmitters and non-transmitters. Also, the ability of transmitter females to eject L3 larvae and the level of infective larvae and the level of infective larvae burden can be determined. Transmission experiments carried out by this technique showed that extrinsic incubation period for transmission L3 larvae by Cx. pipiens is different from feeding technique, it was indicated that a high number of the non- transmitter females harboured L3 larvae in their proboscis, i.e. not every infective female is capable of ejecting L3 larvae during feeding and hence, is not able to infect man under experimental conditions. It was indicated that the transmitter female of Cx. pipiens is found to harbour significantly higher L3 larvae than the non-transmitter one but the number of transmitter females is less than that of non transmitter ones. Ejection of L3 larvae from the mosquito vectors during filaria transmission was tested under different stimulating media. Seven different media were tested. Based on the present results, precise informations about the preferred media that stimulate the ejection of L3 larvae from infected Cx. pipiens females were obtained. It was found that, sweat is the most preferred medium which could stimulate the ejection of infective filarial larvae [L3], followed by the mixture of sweat and blood while no ejection occurred in air medium. The third medium was a mixture of sugar solution and+ blood+then+ sugar+ rsolution+ and+ lastely+ water

effect of chronic irradiation on the biology of musca domestica L. [diptera, muscidae] through successive generations

Two days old pupae Musca domestica L. from Fl, F3, F5, F8, F11 and fl4, were exposed to 4-doses of gamma irradiation namely 700, 900, 1100, and 1300 r. A reduction in percentage of adult emergene through successive generations was noticed with no significant effect on sex ratio. At higher and lower doses, of M. domestica L

Mosquito distribution in Qalyobiya Governorate, Egypt

Eight culicid species, Culex pipiens, C. antennatus, C. univittatus, Aedes caspius, Aedes detritus, Culesita longairiolata, Ano. pharoensis, Ano. tenebrosis. Culex pipiens were found in five indicator areas. Ten wells and old Sakia pits were chosen from five villages in Qaluobiya Governorate throughout one year. Wells and old Sakia pits were found to play a major role in mosquito problem in Qaluobiya Governorate. Extensive aquatic vegetation specially duck-weed had a marked effect on breeding of culicidae immature stages

Larvicidal activity of bacillus thuringiensis serotype H-14 on certain Egyptian mosquito species

Laboratory experiments were carried out to screen the susceptibility of five Egyptian mosquito species to the toxic effect of a standard formulation of B. thuringiensis H-14 [IPS82 Lot 91509] prepared by Pasteur Institute. Tests were carried out under laboratory conditions using the method described by [De Barjac 1978]. The obtained results indicated that all tested mosquito species were susceptible to the toxic agents of this formulation. However, degree of susceptibility varied according to mosquito species. The highest rate of mortality was found among the larvae of Aedes capius PaIlas followed by Culex Pipiens, Culex antennatus, Anopheles multicolor and Anopheles phareonisis

effect of chronic irradiation on the biology of culex pipiens molestus forsk [Diptera, culicidae] through successive generations

One-day-old pupae Culex pipiens molestus Forsk from F[1], F[3], F[5], F[8],F[11] and F[14] were exposed to 4 doses of gamma irradiation namely 500, 1000, 2000, and 4000r. A reduction in the percentage of adult emergence through successive generations was noticed with no significant effect on the sex ratio. At higher and lower doses, the survival rates of both sexes resulting from radiation selected population were significantly longer than the control. Fecundity and fertility were also affected by the chronic exposure, reduction in egg production and egg hatchability were observed, the higher the dose the lower the percentage of hatchability. No resistance was developed to chronic exposure by the radiation selected population of the Egyptian mosquito C. P. molestus