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Biocontrol agents and oviposition attractants are promising alternate tools/adjuncts for mosquito control. Using oviposition attractants, monitoring of vector populations, especially Aedes species, could be carried out so as to plan control measures, or to attract gravid females to lay eggs at chosen sites and kill the emerging larvae by combining a larvicide. Microorganisms inhabiting mosquitobreeding sites (Androsov et al. 1986) play a major role in the decomposition of detritus present in the habitats leading to the production of several metabolites. Some of these metabolites are likely to act as oviposition attractant and/ or stimulants for mosquitoes. Therefore, in the present study culture filtrates containing metabolites of a few bacteria were examined for oviposition attractancy and the results are presented hereunder. Cultivation of bacteria -Nutrient broth (NB) containing (wt/v %) glucose (0.5), beef extract (0.5), sodium chloride (0.5), and peptone (0.5) in distilled water at a pH 7.5 was used to grow P. (Yousten et al. 1980). And to grow B. sphaericus the medium NYSM without glucose was used. For the cultivation of A. brasilense a medium containing (wt/v %) yeast extract, 1.0 in distilled water, pH 7.5 was used. A loop full of bacterial growth from an agar slope was transferred to 10 ml of growth medium (in a boiling tube) and incubated for 8 h on a rotatory shaker at 250 rpm and 28 ± 2 o C. The culture was then transferred to 50 ml of growth medium (in 250 ml capacity Erlenmeyer flask) and incubated, as stated above, for 10 h. Five ml of this inoculum was transferred to 500 ml of production medium (in 2 l flask) and incubated for 48 h. Then, the cell-mass from the culture was harvested by spinning at 10,000 rpm for 10 min. The cell-mass was discarded and the cell-free supernatant was used as test material for oviposition attractancy tests. MATERIALS AND METHODS Bacterial strains -Determination of optimum concentration of bacterial culture filtrates for oviposition attractancy testThree-day-old Culex quinquefasciatus females, obtained from a colony maintained at VCRC, were fed on fowl blood and maintained for two days on raisins at 28 ± 2 o C and 70-80% RH. Gravid females were used for determination of oviposition attractancy of various compounds. Different concentrations (5-3000 ppm) of the test materials were prepared in tap water. Two hundred ml of each test preparation held in disposable cups (capacity, 250 ml) was placed in a mosquito cage (size, 55 x 55 x 55 cm). Tap water was used as a control. One hundred fully gravid female mosquitoes were released into the cage. For each test, one cage was used and at any given time, not more than five disposable cups were kept on the floor of the cage. Four cups with four different concentrations of the culture filtrate were on four corners and the fifth cup with tap water (control) was at the center of the cage. The cages were kept at 28 ± 2 o C and 70-80% RH. Experiments were set up

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Methanolic extracts of 20 medicinal plants were screened at 1-10 mg/ml for in vitro macrofilaricidal activity by worm motility assay against adult Setaria digitata, the cattle filarial worm. Four plant extracts showed macrofilaricidal activity by worm motility at concentrations below 4 mg/ml and an incubation period of 100 min. Complete inhibition of worm motility and subsequent mortality was observed at 3, 2, 1 and 1 mg/ml, respectively, for Centratherum anthelminticum, Cedrus deodara, Sphaeranthus indicus and Ricinus communis. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) reduction assay was carried out at 1 mg ml(-1) and 4-h incubation period, and the results showed that C. deodara, R. communis, S. indicus and C. anthelminticum exhibited 86.56, 72.39, 61.20 and 43.15% inhibition respectively in formazan formation compared to the control.

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Transferrin is a defence protein known to be up-regulated upon infection of parasites/pathogens in Aedes aegypti mosquito. However, no information is available on its up-regulation in Culex quinquefasciatus, the vector of bancroftian filarial parasite. In the present study, enhancement of transferrin in C. quinquefasciatus infected with Wuchereria bancrofti is demonstrated through amplification of the specific mosquito transcript, its sequencing, cloning, and expression. By using two oligonucleotide primers, a 950-bp polymerase chain reaction product was obtained from the first strand cDNA made from RNA of C. quinquefasciatus infected with W. bancrofti. A 707-bp sequence encoding the mature portion of transferrin was confirmed by sequencing the product. This is the first report of transferrin expression in C. quinquefasciatus. The deduced amino acid sequence shared 85% homology with A. aegypti transferrin precursor molecule. Western blot analysis of haemolymph proteins of infected C. quinquefasciatus with antibodies raised against recombinant transferrin protein showed binding to a 66-kDa protein, confirming its identity as transferrin. Hence, this molecule also could be added to the list of immune molecules of C. pipiens group, such as the defensin, gambicin, and cecropin, which are already known.

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Secondary metabolites produced by (Davis & Bowen 1994). By using oviposition attractants, vector mosquitoes could be attracted to chosen sites for laying eggs. Various chemicals serve as oviposition attractants for mosquitoes even when present in relatively small quantities (Beehler & Mulla 1993). Oviposition attractants are known to be produced by microorganisms also (Hazard et al. 1967, Rockett 1987, Hasselschwert & Rockett 1988, Beehler et al. 1994. Among deuteromycetes fungi, Trichoderma species are known to produce aromatic/volatile secondary metabolite(s) (Kikuchi et al. 1974, Keszler et al. 2000, SarhyBagnon et al. 2000, Kalyani et al. 2000. In the present study secondary metabolite(s) produced by the fungus Trichoderma viride was evaluated for oviposition attractancy against gravid females of Culex quinquefasciatus and the results are presented in this paper. MATERIALS AND METHODSA natural strain of T. viride (F24), obtained from the culture collection of Vector Control Research Centre (VCRC) was subcultured on Sabouraud Dextrose Agar (SDA) (glucose 40 g; peptone 10 g; agar 20 g; distilled water 1000 ml; pH 4.5-5.0) slants and incubated for 5 days to attain sporulation. Then a loopful of spores were inoculated to 50 ml Sabouraud Dextrose Broth (SDB) (glucose 40 g; peptone 10 g; agar 20 g; distilled water 1000 ml; pH 4.5-5.0) in a 250 ml conical flask and incubated on a rotary shaker (New Brunswuck Scientific Co., New Jersey, USA) at 110 rpm and at 30°C for 3 days. From the seed culture, 2% of the inoculum was transferred to 200 ml of SDB and incubated for 15 days at the above mentioned conditions. The culture was filtered through Whatman no.1 filter paper, the mycelial mass was discarded, and the culture filtrate was lyophilized. The residue was dissolved in 50% ethanol at a ratio of 500 mg of residue in 10 ml of ethanol. This formulation was code named as VCRC F24 and used for oviposition attractancy tests.Determination of optimum concentration of VCRC F24 and p-cresol for oviposition attractancy test -Threeday-old Cx. quinquefasciatus Say female mosquitoes, an indigenous strain obtained from a laboratory colony maintained at VCRC, were fed on fowl blood and maintained for two days on raisins at 28 ± 2 o C and 70-80% RH. Gravid female mosquitoes were used for the determination of oviposition attractancy using standard procedure (WHO 1963). Different concentrations (5 µg ml -1 , 10 µg ml -1 and 15 µg ml -1 ) of VCRC F24 and a known oviposition attractant, p-cresol (a volatile pentane), was prepared in tap water. In the case of p-cresol, a stock solution of 1mg ml -1 was made in ethanol and diluted to the required levels with tap water. Tap water with equal amount of ethanol served as control for VCRC F24 and p-cresol. Two hundred ml of each of the test/control solutions held in disposable bowls (capacity, 250 ml) were placed in the floor of a mosquito cage (size, 55 x 55 x 55 cm). One hundred numbers of fully gravid female mosquitoes were released into the cage. For each test at any given time, not more...