Irigenin belongs to family of isoflavonoids, isolated from Iris Plant of Kashmir Himalaya. A rapid and specific reverse phase high pressure chromatography (RP HPLC) method for quantitative analysis of irigenin in the different species of Iris Plant was developed. The samples were analyzed on RP-C18 e column (chromolith, 5μm, 4.6×100 mm). The HPLC system was operated at ambient temperature (±30c). The mobile phase consisted of methanol: water. The detecting wavelength at 260 nm and flow rate of 0.6 ml/min. The standard irigenin was diluted using the mobile phase at a known concentration of 1mg/ml; the sample was filtered through sample filter of 0.45 μ pore size. The filtrate was introduced on to a reverse phase analytical column. The content of irigenin in the different species of Iris Plant was determined. The HPLC showed an excellent performance in separating the irigenin in different species of Iris Plant. Furthermore, the antipathogenic activity. The test compound at each respective concentration was found to be statistically superior against scab. Furthermore, the test compound @ 5000 ppm proved significantly most effective by providing (82.49%) inhibition in the mycelia growth of apple scab. It was followed by fusarium (77.27%) at 5000 ppm. Lowest reduction in mycelia growth (65.78%) was recorded in marssonina and did not differ significantly from Alternaria (67.47%) at 5000 ppm. Furthermore, lowest inhibition of mycelia growth was recorded at 1000 ppm. Similar trend was recorded for rest of the pathogens i.e. highest reduction at 5000 ppm, lowest at 1000 ppm and at 2000, 3000 and 4000 ppm it ranges between the first two but increases with increase in concentration. From this study irigenin is potent compound which can be used for controlling the growth of respective pathogens.