Effect of temperature on the effectiveness of Bacillus thuringiensis var. israelensis against Culex pipiens molestus Forsk larvae

2009 ◽  
Vol 94 (1-5) ◽  
pp. 408-412 ◽  
Author(s):  
A. I. Farghal
2006 ◽  
Vol 72 (8) ◽  
pp. 5673-5676 ◽  
Author(s):  
Takeshi Ito ◽  
Tomonori Ikeya ◽  
Ken Sahara ◽  
Hisanori Bando ◽  
Shin-ichiro Asano

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.


1994 ◽  
Vol 126 (4) ◽  
pp. 1061-1065 ◽  
Author(s):  
Kees van Frankenhuyzen

AbstractThe relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.


1955 ◽  
Vol 46 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R. H. Wharton

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.


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