The research aimed to isolate and characterize local entomopathogenic fungi from different agricultural ecosystems and assess their pathogenicity against cowpea aphid. Forty soil samples were collected from different ecosystems. In total, 38 fungal isolates were collected from the cadavers' exteriors of Galleria mellonella larvae. Microscopic observation of these fungal isolates revealed that they belonged to nine fungal genera among them Metarhizium sp. (3 isolates) and Beauveria sp. (5 isolates). Primary experiments showed different bioactivities of the isolates of the two selected genera against the target insect. Only Metarhizium isolates (M3 & M5) and Beauveria isolates (B1 & B5) were selected for further investigations. Identification of fungal cultures by morphological characters, molecular characterization, ITS sequencing, and NCBI Blast showed that two isolates were confirmed as M. anisopliae and two isolates as B. bassiana. The bioassay evaluation revealed that M. anisopliae (M3 and M5) and B. bassiana (B1) exhibited significant virulence against A. craccivora, as evidenced by their high LT50 and LC50 values and substantial sporulation on the cadavers. Therefore, they could be used for the formulation of pesticides targeting this pest on cowpea and other vegetable crops.

Laboratory experiments were carried out to de-termine the bioeffects of an isolate of ento-mopthogenic fungi Beauveria bassiana (Bals.) and Biofly a commercial product of B. bassiana, on the 1st instar larvae of mushroom fly, Bradysia ocellaris (coms). The bioactivity of B. bassiana was tested, using five concentrations of B. bassi-ana on some biological criteria of the mushroom fly, by calculating LC50 values after three and sev-en days of treatment. Results indicated that the mortality rates percentage increased with the in-crease of the concentrations used and the period after treatment. The highest percentage of mortali-ty occurred within the first seven days following treatment. Statistical analysis of the obtained lar-val-pupal and adults period and weight revealed significant differences between treated and non-treated insects.

The efficacy of the entomopathogenic fungus Beaveria bassiana Saudi Arabian isolate (B-SA3)was evaluated against the red palm weevil, Rynochophorus ferrungineus (Oliv.).The mentioned isolate was assessed on the different developmental stages of the red palm weevil through toxicity tests, i.e. determination of lethal concentration and lethal times to kill 50% of treated insects. The results showed that 8th instar larvae were the most tolerant followed by pupa to B.bassiana as their LC50 values were 3.75x 108 and 3.78x 107 conidia/ ml, respectively. Meanwhile, 4th instar larvae were the most susceptible to infection by B.bassiana (B-SA 3), as LC50 value was 3.25x 106 conidia/ ml, which proved insignificantly different to that determined in adult weevils, i.e. 4.18x 106 conidia /ml. Furthermore, LT50 values were very similar in these latter mentioned developmental stages in any considered concentration; meanwhile, LT50 was much longer in 8th instar larvae than the other considered instar and/or developmental stages. The fungus B. bassiana was most virulent to eggs of the red palm weevil as none of the eggs hatched following their treatment with any of the considered concentrations (ranging between 5x 109 to 5x105 conidia /ml). Moreover, germination viability of harvested conidia of B.bassiana stored at -4°C was insignificantly affected up to the 10th month storage period and was well above 90%. However, germination percentage of conidia then decreased to 70.27% after 16 months of storage. Also, the virulence of the stored conidia was tested after 1, 6, 12 and 16 months on adult red palm weevils, the LC50 values were 3.75x106, 4.66x106, 4.17x107 and 3.37x108 conidia/ ml, respectively. These results show that there was a significant decrease in the virulence of the tested fungus when the duration of storage period was more than 10 months.