TOXICITY OF SOME MICROALGAE TO THE CITRUS BROWN MITE EUTETRANYCHUS ORIENTALIS (KLEIN) | ||||
Al-Azhar Bulletin of Science | ||||
Article 17, Volume 24, Issue 2-C, December 2013, Page 81-92 PDF (403.94 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/absb.2013.6421 | ||||
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Authors | ||||
M. A. ABOU SHOSHA* 1; TAHER M. TAHA2; MUSTAFA A. FAWZY3 | ||||
1Agricultural Zoology and Nematology Department, Faculty of Agriculture, Al-Azhar University, Assiut, Egypt. | ||||
2Botany and Microbiology Department, Faculty of Agriculture, Al-Azhar University, Assiut, Egypt. | ||||
3Botany and Microbiology Department, Faculty of Science, Assuit University, Egypt. | ||||
Abstract | ||||
The citrus brown mite Eutetranychus orientalis is a common spider mite, which is a harmful pest in citrus orchards in Egypt. The toxic activities of some microalgae isolated from Egyptian soils and water are studied against E. orientalis. The toxicity of whole cultures (culturing broth and cell) of seven algal strains was tested against E. orientalis. Three strains out of the tested seven strains showed higher toxicity with mortality percentage reached up to 99 % after 72 h recorded against adult individuals of E. orientalis with a strain of Chlorella minutissima. The toxic activity was also tested against immature individuals and eggs of E. orientalis. The highest mortality percent against immature individuals was observed with C. oocystoids. Eggs were not affected with any of the tested algal strains. When cells and culturing broth were tested separately the activity was higher in culturing broth which means that this activity is due to some extracellular metabolites secreted by algae in their culturing medium. When the organic solvent n-butanol was used to extract the active constituents from the whole cultures (culturing broth and cell), the activity was found to be higher in aqueous phase compared to the butanolic phase. | ||||
Keywords | ||||
Biocontrol; Eutetranychus orientalis; algal toxicity; microalgae; Chlorella | ||||
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