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- Back, C, et al.
(författare)
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High-dosage treatment of a Quebec stream with Bacillus thuringiensis serovar. israelensis : efficacy against black fly larvae (Diptera, Simuliidae) and impact on nontarget insects
- 1985
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Ingår i: Canadian Entomologist. - 0008-347X .- 1918-3240. ; 117:12, s. 1523-1534
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Tidskriftsartikel (refereegranskat)abstract
- A typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.
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- Lacoursière, Jean O., 1958-, et al.
(författare)
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Laboratory study of the influence of water temperature and pH on Bacillus thuringiensis var. israelensis efficacy against black fly larvae (Diptera: Simuliidae)
- 1988
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Ingår i: Journal of the American Mosquito Control Association. - 8756-971X .- 1943-6270. ; 4:1, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- An experimental formulation of Bacillus thuringiensis var. israelensis was used in the laboratory to assess the influence of water temperature and pH on the relationship between concentration, duration of exposure, and mortality of the northern black fly species Simulium decorum and Prosimulium mixtum/fuscum group. Mortality increases in both species with increases in duration of exposure, concentration, temperature and pH. Onset of death is shortened by increase in concentration and temperature. As temperature rises, the concentration of B. t. i required to induce mortality decreases; the sharpest decline occurring between 12 and 18 degree C for S. decorum , and between 4 and 8 degree C for P. mixtum/fuscum larvae. Lower pH induces a loss of efficacy of the B. t. i. formulation on S. decorum larvae at 4 and 12 degree C.
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- Lacoursière, Jean O., 1958-, et al.
(författare)
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Short-term Maintenance System for Black Fly Larvae (Diptera: Simuliidae)
- 1987
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Ingår i: Journal of medical entomology. - 0022-2585 .- 1938-2928. ; 24:4, s. 463-466
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Tidskriftsartikel (refereegranskat)abstract
- A simple, readily transportable apparatus for maintenance of black fly larvae in the laboratory is proposed as an alternative to a full-scale rearing system. This compact apparatus of the compressed-air type can maintain dense populations of black fly larvae without time-consuming manipulation. Large numbers of Simulium venustum Say complex, Simulium decorum Walker, and Prosimulium mixtum Syme & Davies group larvae (> 1,200 larvae per liter) were maintained successfully at low temperature in our laboratories for 3 – 5 mo. Mortality rates for mid- to late instars of each of the three species were <5%. Large areas of removable substrate allow easy access to larvae. This system can be used in the field to transport larvae to the laboratory, where they can be maintained or reared to the adult stage.
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- Rehnstam, Ann-Sofi, 1959-, et al.
(författare)
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Identification of Vibrio anguillarum in fish by using partial 16S rRNA sequences and a specific 16S rRNA oligonucleotide probe
- 1989
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 55:8, s. 1907-1910
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Tidskriftsartikel (refereegranskat)abstract
- 16S rRNA from seven different Vibrio anguillarum strains was partially sequenced and compared. From this sequence information we could design a 25-base-long oligonucleotide and use it as a specific probe for identification of V. anguillarum. This was determined by RNA-DNA colony hybridization and slot-blot hybridization. Strong, specific hybridization to the probe was observed for all V. anguillarum strains tested. Furthermore, no cross-hybridization could be seen against five other bacterial species. The detection limit was 5 x 10(3) bacteria per ml. It was even possible to detect V. anguillarum, by slot-blot hybridization, directly in a homogenized kidney from a fish that had died of vibriosis. The partial sequence information revealed small but significant differences between strains of the same species. These sequence differences are sufficiently significant to allow serotyping on the RNA level. Comparing strains of different serotypes revealed a 10-base and an 11-base difference in V. anguillarum serotypes O8 and O9, respectively, in a 122-base partial sequence.
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