Mosquito density forecast from flooding: population dynamics model for Aedes caspius (Pallas).

Insect population dynamics depend strongly on environmental factors. For floodwater mosquitoes, meteorological conditions are crucial in the rhythm of mosquito abundances. Indeed, rainfall triggers the egg hatching after flooding breeding sites, and temperature controls the duration of the aquatic immature development up to adult emergence.

Potency of products based on Bacillus thuringiensis var. israelensis: interlaboratory variations.

Six quality-control laboratories in 4 countries independently bioassayed aliquots of a flowable formulation of Bacillus thuringiensis var. israelensis (B.t.

International indoor and outdoor evaluation of Bacillus sphaericus products: complexity of standardizing outdoor protocols.

Only one Bacillus sphaericus strain, strain 2362, is currently used commercially to control Culex larval populations. A reliable methodology, easily used, was developed to identify new strains for field application. Larvicidal activities of 3 highly mosquitocidal strains, strains C3-41, Mal, and LB24, previously selected in the laboratory, were compared with that of strain 2362 in tropical and European countries.

Resistance to Bacillus sphaericus involves different mechanisms in Culex pipiens (Diptera:Culicidae) larvae.

Field Culex pipiens pipiens (L.) mosquitoes that were collected after a control failure with Spherimos in southern France developed high resistance (> 10,000-fold) to Bacillus sphaericus crystal toxin after < 8 generations of laboratory selection. We show that this resistance is encoded by a single major recessive gene on linkage group I at 22.

Control of Culex pipiens by Bacillus sphaericus and role of nontarget arthropods in its recycling.

Bacillus sphaericus was used to control Culex pipiens breeding in a water treatment settling basin near Montpellier, France. Four treatments with 4 liters/ha (3.6 lb/acre) of commercially available B.

Est-2 and Est-3 polymorphisms in Culex pipiens L. from Southern France in relation to organophosphate resistance.

Est-2 and Est-3 linkage disequilibrium was investigated in 43 natural populations. An association between Est-2(0.64) and Est-3A alleles (or its reverse, Est-3Null and alleles other than Est-2(0.

[Immediate larvicidal activity and residual action of the endotoxin of the serotype H-14 of Bacillus thuringiensis in 2 mosquito biotopes on the French Mediterranean coast].

The primary powder R.153.78 of the serotype H.

[Some effects of a growth inhibitor, Diflubenzuron, on a crab Carcinus mediterraneus (Czerniavsky)].

The effects of Diflubenzuron (N-4-chlorophenylamino carbonyl 2-6-difluorobenzamide) were tested, on a common crab of the Languedocian coasting ponds: Carcinus mediterraneus (Czerniavsky). Seawater was contaminated at two concentrations: 0.2 and 0.

[Progressive acquisition of resistance to chlorpyrifos in Culex pipiens (L.) larvae in the South of France].

A high resistance level has been detected in certain Culex pipiens populations after seven years of chlorpyrifos larval treatments in the Montpellier area (Southern France). The highest rate recorded in 1973 was x 15, in 1974 x 33,3, in 1975 x 47 and in 1976 x 73. The resistance level depends on the application frequency of this larvicide and the various biotope types.

[Comparative action of 31 insecticides on chlorpyrifos-sensitive and resistant Culex pipiens (L.) larvae in the South of France].

In urban and sub-urban areas larval populations of Culex pipiens are now resistant to chlorpyrifos. A replacement compound must be found so 31 pesticides were tested against 3 strains: 2 of them were bred in the laboratory (on sensitive and one resistant) and the third one collected in an area treated with agricultural pesticides and chlorpyrifos. The results show that this last compound induces a cross-resistance only to organophosphorus compounds especially to parathion, chlorpyrifos-methyl, pyrimiphos-methyl, diazinon and Abate.

Esterase polymorphism and sensitivity to Dursban organophosphorus insecticide in Culex pipiens pipiens populations.

Esterase polymorphism and Dursban (O,O-dimethyl-2-pyridylphosphorothioate) sensitivity have been investigated in 12 natural populations and three laboratory strains of Culex pipiens pipiens. This mosquito has two esterase loci, Est-1 and Est-2, which were shown to code esterases of the B group (aliesterases) but not cholinesterases. No correlation between Est-1 polymorphism and Dursban sensitivity was found, but the increase of the Est-2(0.