IMPACT OF EIGHT BACTERIAL ISOLATES OF Bacillus thuringiensis AGAINST THE TWO LAND SNAILS, Monacha cantiana AND Eobania vermiculata (GASTROPODA: Helicidae). | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 4, Volume 33, Issue 4, April 2008, Page 2853-2861 PDF (671.15 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2008.217774 | ||||
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| Authors | ||||
| Marwa A. M. Genena,; Fatma A. M. Mostafa | ||||
| Agric. Zoology Dept., Fac. Agric., Mansoura Univ., Mansoura,Egypt. | ||||
| Abstract | ||||
| Under laboratory conditions, eight native bacterial isolates of Bacillus thuringiensis, were tested for their molluscicidal activity against the two land snails, Monacha cantiana (Montagu) and Eobania vermiculata (Muller) at a constant concentration (7x106 cfu/ ml) using three methods of application. Results revealed that all tested isolates applied via food or soil had no adverse effect on the tested land snails and resulted no mortality in M. cantiana and E. vermiculata as well. However, results clearly indicate the molluscicidal properties of the tested isolates and identify Bt-k64 ,Bt- B33 as well as Bt- W123 as potentially effective against M. cantiana and E. vermiculata when bacterial isolates were introduced to snails via food and soil simultaneously (concomitant treatment). For eight bacterial isolates, the percentage mortality ranged from 33% to 86.6% for the clover land snail, M. cantiana , while in the brown land snail, E. vermiculata the percentage mortality ranged from 6.6% to 53%. after four weeks of treatment B. thuringiensis designated as Bt- K64 was the most effective one against the two land snails, M. cantiana and E. vermiculata with percentage mortality 86.6% and 53.0% , respectively whereas, B. thurinigensis designated as Bt- B123 was the least toxic isolate with mortality 33% and 6.6% respectively. M. cantiana was more sensitive to the tested isolates than Eobania vermiculatum. Moreover, the molluscicidal activity of the three isolates of the bacterium, B. thurinigensis designated as Bt-W123 , Bt-B33 and Bt-K64 at three concentrations (1x106 , 1x107 and 1x108 cfu/ ml) against M. cantina under laboratory condition at 15ºC±3 and 60 ±5% RH. was undertaken. Isolate Bt –B33 and isolate Bt –W123 showed higher toxicity to the target snail than isolate Bt –K64 with mortality increasing with an increase in the concentrations of isolates as well as the period of exposure. At the highest concentration ( 1x108) the bacterial isolate Bt –B33 was the most toxic which killed 53% of the land snail M. cantiana after two weeks from treatment and 73.3% and 86.4% after three and four weeks of experiment | ||||
| Keywords | ||||
| land snails; Monacha cantiana; Eobania vermiculata; isolates; Bacillus thuringiensis; percentage mortality | ||||
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