Mode of Infection of Phyllosticta maculata on Banana as Revealed by Scanning Electron Microscopy

Abstract

The initial infection stages of Phyllosticta maculata on banana were studied using scanning electron microscopy. Conidial germination on the banana leaf surface commenced within 3 h postinoculation to produce a long and slender germ tube. The hyphae developed secondary branches and mostly grew randomly across the leaf surface. Appressoria were formed at the apex of the germ tubes within 18 h postinoculation and were variable in shape. A layer of an extracellular matrix surrounded the appressoria at the pathogenhost interface. On the fruit surface, conidia germinated to produce predominantly swollen germ tubes which functioned as lateral appressoria together with some slender ones. These germ tubes were formed within 3 h postinoculation. There was no stomatal penetration apparent on the leaf; instead, direct penetration through the cuticle with and without the formation of appressoria was observed. Cuticular degradation on the leaf surface was evident with a circular, darkened area around the point of penetration by hyphae or appressoria. The significant role of pycnidia and conidia in the epidemiology of the disease was further demonstrated in naturally infected leaf samples.

The evaluation of acute toxicity, antimicrobial activity of 1‐phenyl‐5‐p‐tolyl‐1H‐1, 2, 3‐triazole, and binding to human serum albumin

“…Symptoms include yellowing of the tissue and formation of small dark brown spots on the leaves and fruit. This devastating disease is extremely relevant for the major banana exporting countries of the world …”

“…This devastating disease is extremely relevant for the major banana exporting countries of the world. [33] TA 2).…”

Phyllosticta taxa from northern Thailand and southern European Russia: a novel species and four new host records

“…Endophytic P. capitalensis also possesses potential antagonistic effects against pathogenic P. citricarpa on citrus (Tran et al 2019). Some Phyllosticta species generate appressoria prior to entering their hosts, for example P. maculata (Wong et al 2013). Phyllosticta species mainly produce melanized appressoria (Sutton 1980;Chethana et al 2021a, b).…”