Illustration of Key Morphological Characteristics of Phytophthora cajani-Pathogen of Phytophthora Blight of Pigeonpea

Abstract

Background: Phytophthora cajani causing the Phytophthora blight (PB) disease of pigeonpea. The disease will rampant during excessive rainfall coupled with hot and humid weather during the cropping season. The present study on micro and macro morphological characteristics can contribute to the identification and specification of biology of Phytophthora spp. There are no detailed studies concerning the characterization of the P. cajani are available with this backdrop the present investigation was taken. Methods: Phytophthora cajani was isolated on V-8 PARP medium, whereas stimulation of zoospores and sporangia was done using the diluted tomato juice broth. Micro and macro morphological characteristics of P. cajani were studied using micrometry and Olympus CX41 phase-contrast microscope. Result: The pathogen was homothallic with amphigynous antheridium and oogonium and able to produce oospore in vitro. Sporangium was nonpapillate, noncaducous, oviod-obpyriform shape. Further, the macro morphological characteristics like mycelial radial growth and colony type were studied. The colony characteristics were dull white, flat and rosette pattern. Other culture characteristics like optimum temperature and RH were mostly consistent with those reported former.