الفهرس | Only 14 pages are availabe for public view |
Abstract Metarhizium anisopliae, Metarhizium flavovridae, Beauveria bassiana, Beauveria brongniartii and Paecilomyces farinosus were used as a biological control agents for the Egyptain cotton leaf-worm Spodoptera littoralis (Boised.), which represents the most severe destructive cotton pest in Egypt and many other countries and leads to a decrease in the national income of our country and pink bollwonn was reported as a serious pest of cotton in 1940, it has since become the most injurious insect pest cotton in many cotton-growing regions of the world. The main points which were discussed in this study could be summarized in the following topies: I-Mass production of the five fungal isolates under study in different growth media. 2-Efficiency of the fungal isolates as a biological control agents against the Egyptain cotton leaf worm S.littoratis and P.gossypiella under laboratory conditions. 3-Protein analysis for fungal isolates by sodium dodocyle sulphate polyacrylamide gel electrophoresis (SDS-PAGE) 4-Determination of aflatoxins by Thin layer chromatographic (TLC) and High performance liquid chromatography (HPLC) The fungi under study were grown on three different media .where M.anisopliae, J.f.jlavovridae, B.bassiana and B.brongniartii exhibits good growth on Yeast Extract Sucrose whereas Paecilomyces farinosus exhibit good growth on Czapek’s-Dox Agar medium. The medium constituents were prepared and adjusted at pH 5.5-6.5. After sterilization, Petridishes were inoculated with the fungal strains and incubated for two weeks at 25° C&50-60% RH. At the end of the incubation period, the supernatant was separated from the mats. Three concentrations were used viz 40, 60 and 80%, these concentrations were made by using ammonium sulphate. The 1st instar larvae of P.gossypiella were mixed in artificial diet with fungal toxin 40, 60 and 80%. from each concentration take I ml and homogenately mixed with 15 gm of artificial diet. The infected larvae were placed in sterile cups containing artifical diet, ten hatched larvae of P.gossypiella were placed on the surface of the diet, all stages were reared and treated under constant conditions of 27±1DC and 80±5%RH. Mortality counts were recorded after 48h of treatments, mortality percentage of Manisopliae after 9 days of treatment was 85.970%. Generally Manisopliae was found to be the most effective isolate against 1st instar larvae of P.gossypiella followed by B. bassi ana, P.farinosus, Mflavovridae then B.brongniartii. The previous same techniques were used except for all stages were reared and treated under constant conditions of 25± 10C &50-60%RH, mortality percentage of B. brongniartii after 12 days of treatment was 83.36%. Generally B. brongniartii was found to be the most effective isolate against I” instar larvae of Slittoralis followed by Pfarinosus, M.jlavovridae, M anisopliae then B. bassiana. Mortality percentage of B. bassiana after 12 days of treatment was 78.53%. Generally B. bassiana was found to be the most effective isolate against 2 nd instar larvae of S.UttoraUs followed by Pfarinosus, B.brongniartii, ManisopUae, M.jlavovridae. The proteins of five isolates mentioned above was extracted from their supernatant and fractioned by SDS-PAGE. SDSPAGE revealed a maximum number of 9 bands, which not necessarily present in all samples. For B.brongniartii there are five bands at conc.80%, four bands at conc.40, 60%. For M anisopliae there are three bands at conc.80%, two bands at conc.60% and one band at conc.40%. In addition to Mflavovridae, P.farinosus and B.bassiana appeared (5, 6, 9) bands at cone. 40, 60, 80% for Mj/avovridae, (3, 4, 5) bands at cone. 40, 60 and 80% for P.farinosus, and (1, 1, 2) bands at concAO, 60 and 80% for B.bassiana. Concentration 80% for all fungi was characteristic by large number of bands then 60, 40%. The five tested entomopathogenic fungi can not produced any types of aflatoxins B1, B::;,G1 and G2 by (TLe) and (HPLC). |