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Fate of spinosad under Egyptian environmental conditions
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Abstract: Spinosad is an insect control agent produced by fermentation of the actinomycete Saccharopolyspora spinosa. The objective of this research was to evaluate the susceptibility of both laboratory and field strains of 2nd and 4th instars larvae of the cotton leafworm Spodoptera littoralis (Boisd.) to spinosad and to evaluate the initial as well as the residual efficacy of spinosad against these instars larvae with three rates of application 50 , 200 and 400 ml / feddan on cotton . In addition assessment of the photodegradation of spinosad was determined. The spinosad was bioassayed after 24, 48 and 72 hours from treatment. The highest efficiency of spinosad was obtained after 72 hours from treatment giving LC50 values 0.888 and 21.061 ppm for both 2nd and 4th instars larvae of the laboratory strain, respectively. The field strain showed susceptibility to spinosad as demonstrated by resistance ratio. The toxicity ratios of spinosad on 2nd and 4th instars larvae were (7.737,30.950 and 61.895 ) and (2.225, 8.899 and 17.798) and also the lethal time required to produce 50% mortality (LT50) were(0.0005, 0.548 and 4.105 days) and (8.056E-9, 0.090 and 0.560 days) for three tested rates of application , respectively . The correlation coefficient between the residual efficacy and time elapsed after application showed negative correlation . Degradation of spinosad in the environment occurs mainly by photodegradation , this study was conducted in order to investigate the role of direct sunlight, ultraviolet rays (UV) and infrared rays (IR) exposure on the stability of spinosad . The rates of decomposition (K) of spinosad were 0.842, 0.109 and 0.022, the corresponding half life values (T1/2) were 19.776, 6.355 and 31.810 hours after exposure to direct sunlight, (UV) and (IR), respectively. So, it appear that spinosad can play important role in developing integrated crop management (ICM) on cotton in Egypt.
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| Publication year |
2005
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| Pages |
811-825
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| Availability location |
معهد بحوث وقاية النباتات
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| Availability number |
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| Organization Name |
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| City |
الجيزة
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| serial title |
المؤتمر العلمي الثالث لشعبة البحوث الزراعية والبيولوجية-المركز القومى للبحوث
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| ISSN |
1110-6336
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| Author(s) from ARC |
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| Agris Categories |
Pests of plants
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AGROVOC
TERMS |
Actinomycetales.
Fermentation.
Insect control.
Microbial pesticides.
Photolysis.
Spodoptera littoralis.
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| Publication Type |
Conference/Workshop
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