ACTIVATION OF Bacillus thuringiensis var. kurstaki BY USING SOME CHEMICAL COMPOUNDS FOR INCREASING ITS EFFICACY | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 6, Volume 4, Issue 11, November 2013, Page 959-972 | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2013.87661 | ||||
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| Authors | ||||
| E. S. MANSOUR1; M. S.I. Shalaby2; N. A. Abou Zeid2 | ||||
| 1Cotton Pest Insecticide Research Department, plant Protection Research Institute, A.R.C., Dokki Giza, Egypt. | ||||
| 2Crop Pests Research Dept., Plant Protection Res. Institute, Agric. Res. Centre, Giza, Egypt | ||||
| Abstract | ||||
| Second instar larvae of Spodoptera. littoralis were fed on castor bean leaves treated with different concentrations of Dipel (Bacillus thuringiensis var. kurstaki), Helban (chemical insecticide) and combination of Dipel with LC10 of Helban, 1% sodium chloride ( NaCl ) or Dipel with 1 % sodium bicarbonate( NaHCO3 ). Larvae fed for 24 hours on treated castor bean leaves dipped for one minute at each concentration used of the tested materials. The LC50 value of Helban was 10.26 p.p.m (estimated after 24h.from treatment) ,while the LC10 was 5.7 p.p.m., bioinsecticide treatment proved to be effective against 2nd instar larvae of S. littoralis where, the recorded LC50 value was15.2 × 104 I.U after 5 days of treatment. While the LT50 value was 4.78 and 2.75 days at concentrations of 16 and 20 × 104 I.U., respectively. In case of Dipel + 1 % NaHCO3, this treatment did not offer effect more than Dipel treatment only, where the estimated LC50 value was 14.92 × 104 I.U. after 5 days of treatment. While the LT50 values were 4.78 and 2.03 days at concentrations of 16 and 20 × 104 I.U., respectively. The most effective toxic treatment among all treatments were that of Dipel + 1% NaCl where the estimated LC50 value of this treatment was 5.39 × 104 I.U. 5 days post treatment , While the LT50 values were 4.831, 3.081 and 2.096 days at concentrations of 4,8 and 12 × 104 I.U., respectively. To evaluate the joint action of the bioinsecticide Dipel combined with LC10 of Helban two methods were followed, the first by determining the LC50 values and the second by estimating the Co-toxicity factor. The LC50 values were 6.5 × 104 I.U. + 5.7 p.p.m. The low concentrations of Dipel when mixed with LC10 of Helban produced potentiation, while the high concentrations produced additional effects. | ||||
| Keywords | ||||
| Bacillus thuringiensis var. kurstaki; Spodoptera. Littoralis; chemical insecticide; sodium bicarbonate; sodium chloride | ||||
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