In this study, chemical and bio-control agents were  evaluated for their efficiency to control of  citrus fruit-rot disease  caused Alternaria citri  (K2) both, in vitro and in vivo trials. The most effective fungicides were score, montro and Iprodione compared with other fungicides depend on Ec50 and Ec90. While, the fungicide Pyraclostrobine had moderate effect on linear growth of A.  citri. Meanwhile, the Coprax, Coprareekh and Azoxystrobine were the least effective fungicide at Ec90.  Trichoderma harzianum and Bacillus subtilis tested showed antagonistic action effect to a highly pathogenic isolate of Alternaria citri, with different degrees of inhibition. T. harzianum was the most effective compared with B. subtilis, in vitro trials. Also, all fungicides were evaluated on incidence of citrus fruit rot disease in vivo trials.  The disease incidence was reduced, but with different degrees. In addition, using T. harzianum, B. subtilis, B. megaterium (Bio-ARC) and Trichoderma   album (Bio-Zeid) decreased    incidence of citrus fruit rot disease. On the other side, T. harzianum showed the highest suppressive effect against citrus fruit rot pathogen. Generally, all tested fungicides and bio-agents were effective against the causal fungus in vitro and in vivo trials, but with different degrees.

Wady El Natroun high way (Beer Hooker Area) in a private orchard in a sandy soil under drip irrigation system with saline water.  in 2015 and 2016 seasons. Chinese tangerine (Citrus tangerine) transplant were budded on three rootstocks namely sour orange (Citrus aurantum, mion), volkamer lemon (Citrus volkameriana, Tem) and X639 hybrid between (Cleopatra mandarin × Ponicurus trifoliata) grown under saline conditions to study the effect of foliar  application of antioxidants namely ascorbic and salicylic acid on vegetative growth and leaf mineral contents. Results showed that, Volkamer lemon rootstock surpassed sour orange and x639 rootstocks under saline conditions, the highest incremental percentage young tree height, stem diameter, number of leaves per shoot and leaf area were registered by Chinese tangarine scion budded on Volkamer lemon rootstock. Among selected antioxidants ascorbic acid at the concentrations of 800 ppm recorded the highest significant values for vegetative growth parameters and surpassed salicylic acid. Also Chinese mandarin scion budded on volkamer lemon accumulated the highest concentrations of nitrogen (N), phosphorus(P), magnesium(Mg), and chloride (Cl-) and the lowest concentration of sodium (Na+). Chinese mandarin scion budded on sour orange rootstock accumulated the highest concentrations of potassium (K) while Chinese tangerine scion budded on x639 accumulated the highest concentrations of sodium (Na).