The effect of Metarhizium acridum and four bioactive compounds (Neem, L- Glutamic acid, Schinus molle and abamectin) in sole treatments and in combination with M. acridum was studied on the mortality of 5^th nymphal instar of desert locust Schistocerca gregaria as well as the time mortality responses and the ultra-structure of females ovary. The obtained results showed that mortality in case of Metarhizium acridum treatment reached to 100% after 14 days, while  in case of neem treatment   the mortality reached to  60 % after 12 days, at the same time the mortality reached up to 20 % after 10 days post treatment with L- Glutamic acid, but such mortality reached to 50 % after 14 days post treatment with Schinus molle extract, finally the mortality reached to 60 % after 11 days of abamectin treatment. All the mixtures with M. acridum caused 100 % mortality by the 5^th day post treatment. However the sole treatments caused long time to kill 50 % of treated insects (LT₅₀), where the LT₅₀ of M. acridum was 7.261 day as the fastest treatment, while all mixtures caused accelerate in the mortality,but the best result was obtained in case of M. acridum + neem treatment which  LT₅₀ was only1.625 day.                 Any way there were different effects on ultra-structure of the ovary as result of treatments used. Such effects varied between changes in nucleus shape to changes and destruction of nuclus it self.