Morphological Characterization of Phytophthora infestans and its Growth on Different Growth Media.

Phytophthora infestans is a destructive pathogen in the tropical and the sub-tropical areas of the world. Identification of pathogens is very important to find successful disease control strategies. Here, we isolated and identified P. infestans, as well as, determined the morphological characteristics, on different media. The phenotypic characteristic of the isolates were observed as fluffy cottony growth with striated pattern. The average length of sporangia among the isolates collected during 2017 from potato growing areas of Punjab ranged from 14.94 to 47.89 µm, and mean breadth of sporangia varied from 10.44 0 to 23.67 µm. During 2018, among all districts, isolate Jhg-22 showed the highest length (46.64 µm) and breadth (22.17 µm) followed by Shl-25 (46.59 µm) and breadth (22.61 µm), Oka-24 (46.31 x 21.72 µm) while the lowest value measured by Cht-14 (16.05 x 13.39 µm). The best growth and sporulation of P. infestans revealed on Rye agar media compared with other media, while the minimus growth was observed on carrot agar media across most isolates. Therefore, the determination of morphological characteristics for plant-pathogen may add knowledge of the taxonomic behavior of pathogen. The usage of various growth media is providing a useful pattern of the growth that can be utilized in determining the best possible control of late blight disease. [ABSTRACT FROM AUTHOR]