Abstract: The effect of green alga Chlorella vulgaris cells extract as foliar spray on nutrient status, growth and yield of superior grapevines was studied and compared with micronutrients foliar fertilizer. Application of algal extract at 25 to 100% had an announced effect on percentages of bud burst and fruiting buds rather than the check treatment. The effect was obviously appeared till 50% concentration, while the promotion was slight with using concentrations above 50%. Growth characters namely leaf area, shoot length and number of leaves/shoot were greatly stimulated in response to application of Algal extract at 25 to 100% rather than the check treatment. There was a slight stimulation when using algal extract at concentrations above 50%. A progressive increase on percentages of N, P and K in the leaves was observed as a result of increasing concentration of algal extract till 50% while with concentrations above 50% the increase was slightly appeared. Yield expressed in weight and number of clusters as well as berry weight were gradually improved in response to increasing algal extract concentrations. Using algal extract above 50% had neglectable effect. Therefore, 50% concentration is suggested to be beneficial from economical point of view. Spraying algal extract at 25 to 100% was accompanied with hastening fruit quality compared to the untreated vines. The advancement was corresponded to increase concentrations of algal extract. Slight promotion was detected on fruit quality as a result of using algal extract above 50% which increased TSS, TSS/Acid ratio and total sugars and decreasing total acidity rather than control.
