| Titles |
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English :
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Evaluating the toxic and latent efficacy of spinosad against the cotton leafworm, Spodoptera littoralis (Boisd.)
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Arabic :
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(تقييم التأثير السام والمتأخر للمبيد الحيوي سبينوساد ضد دودة ورق القطن)
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| Abstract |
The objective of this study is to evaluate the toxicity as well as the latent efficacy of spinosad against the 4th instar larvae of the cotton leafworm, Spodoptera littoralis (Boisd.). Different bioassays namely; dipping, contact to a surface film and immersion techniques were used in this investigation. The biocide was bioassayed after 24, 48, 72 and 96 hours. The highest toxicity of spinosad was noticed after 96 hours. Results illustrated the superiority of dipping technique for the 4th instar larvae to the biocidal action of spinosad. The efficiency of the bioassay techniques reflecting the larval susceptibility could be descendingly arranged as follows: dipping, immersion and contact to a surface film. The corresponding LC50 and LC90 values against the tested larvae after 96 hours were 122.85 & 518.61; 129.90 & 608.78 and 141.34 & 978.38 ppm, respectively. The 4th instar larvae of S. littoralis showed moderately susceptibility to the biocidal action of spinosad as demonstrated by the toxicity ratios. The toxicity ratios of all bioassay techniques were less than 1.00. The susceptibility index as well as the potency level expressed as numbers of folds at both LC50 and LC90 values increased with increasing the period of determination. The latent effects of spinosad on the pupation as well as the adult emergence were determined. The corresponding EC50 and EC90 values associated to quintals scoring of pupation due to dipping, immersion and contact to a surface film of bioassays were 36.24& 251.95; 50.02 & 549.34 and 63.57 & 711.97 ppm, respectively. Whereas the corresponding IC50 and IC90 values associated to inhibition of the adult mergence were 7.28 & 215.44; 43.52 & 291.42 and 54.12 & 386.07 ppm, respectively.
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| Publication year |
2006
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| Pages |
6725-6733
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| Organization Name |
Plant Protection Research Institute (PPRI)
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| City |
المنصورة
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| serial title |
مجلة جامعة المنصورة للعلوم الزراعية
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| Author(s) from ARC |
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| Publication Type |
Journal
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