Assessments the toxic effects of entomopathogenic bacterium, Bacillus thuringeinsis subsp. kurstaki, and methomyl insecticide on larval instars of the greater sugarcane borer; Sesamia cretica (Lederer)

Aly, Mohamed Z. Y.; Soliman, Mahmoud M. M.; Mohamed, Ebrahim E.E.; Dahi, Hassan F.; Salem, Sherehan A. R.

doi:10.21608/eajbsf.2011.17431

Assessments the toxic effects of entomopathogenic bacterium, Bacillus thuringeinsis subsp. kurstaki, and methomyl insecticide on larval instars of the greater sugarcane borer; Sesamia cretica (Lederer)

Document Type : Original Article

Authors

¹ Zoology Department (Entomology), Faculty of Science (Qena), South Valley University

² Plant Protection Department, Faculty of Agriculture (Qena), South Valley University

³ Plant Protection Research Institute, Giza, Egypt

10.21608/eajbsf.2011.17431

Abstract

This study was conducted to evaluate the efficacy of the bio-insecticide Bacillus thuringiensis (Dipel 2x^® 6.4 % WP) against, 1^st and 2^nd instar Larvae of Sesamia cretica compared with methomyl (Lannate 90 % SP). After 48 hours from treatment, The LC₅₀ value of B. thuringiensis for 1^st instar and 2^nd larvae were 0.00526 and 0.7 gm, respectively. While the LC₅₀ of methomyl after 24h. for 1^st instar and 2^nd larvae were 3394 and 5481 ppm, respectively. After treatment of 1^st and 2^nd instars larvae of S. cretica with LC₅₀ concentrates of B. thuringiensis, the average larval duration of S. cretica were (36.53 & 24.69) and (33.78& 20.31) days for treated and untreated, respectively. In addition, the pupation percentage was (47 & 92 %) and (18 & 84 %) for treated and untreated, respectively. The larval mortality percentage was (53 & 8 %) and (82 & 16 %) for treated and untreated, respectively. The pupal weight for (treated & untreated), S. cretica were (0.1887 & 0.184 gm) and (0.1842 & 0.1601 gm) when it treated as 1^st and 2^nd instars larvae, respectively. Furthermore, the pupal duration were (12.14 & 10) and (10.44 & 9.83 days) for (treated & untreated), when S. cretica treated as 1^st and 2^nd instar larvae, respectively. The total adult emergence for 1^st instar and 2^nd instar larvae were (94 & 100%) and (100 & 100%) for treated and untreated, respectively.
On the other hand results indicated that, after treatment of 1^st and 2^nd instar larvae of S. cretica with LC₅₀concentrates of methomyl, the average larval duration of S. cretica were (31.41 & 24.69) and (33.87& 20.31) days for treated and control, respectively. The pupation percentage was (34 & 92 %) and (28& 84 %) for treated and untreated when S. cretica treated as 1^st and 2^nd instars larvae, respectively. The larval mortality percentages were (66 & 8 %) and (72 & 16 %) for treated & untreated, respectively. The pupal weight for treated and control, were (0.1626 & 0.184 gm) and (0.1994 & 0.1601 gm), respectively. The pupal duration were (12.41 & 10) and (10.83 & 9.83) days for treated and untreated, respectively. The total emergence percentage for 1^st instar larvae were (100 & 100 %) and (85.7& 100%) for 2^nd instar larvae for each (treated & untreated), respectively.

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