New report of Alternaria alternata causing leaf spot of Aloe vera in Pakistan.

Bajwa, Rukhsana; Mukhtar, Irum; Mushtaq, Sobia

A leaf spot disease was observed on Aloe vera plants as small, circular to oval dark brown necrotic sunken spots on the leaves. Infected tissues collected from different sites in diseased fields were cultured on malt extract agar medium, and the pathogen was identified as Alternaria alternata on the basis of morphological and cultural characteristics. The fungus produced effuse, olivaceous black colonies with dark olive-green margins, and abundant branched septate, golden brown mycelium. The conidiophores were branched, straight, golden-brown, smooth-walled, measuring up to 60 μm long by 3 μm wide with one conidial scar. The conidia were obpyriform, golden-brown, smooth-walled, produced in long branched chains, with a short pale beak. Pathogenicity tests conducted on healthy potted aloe plants in a glasshouse showed typical leaf spot symptoms after four to seven days. This is the first report of a leaf spot disease of A. vera in Pakistan.

ALTERNARIA; LEAF spots; NECROTIC enteritis; MYCELIUM; CONIDIA; MALT

Canadian Journal of Plant Pathology, 2010, Vol 32, Issue 4, p490

0706-0661

Academic Journal

10.1080/07060661.2010.510644