A new leaf and sheath brown spot of foxtail millet caused byBipolaris australiensis

Abstract

Abstract.A new leaf and sheath spot disease of foxtail millet caused by Bipolaris australiensis was found in Iran. The causal agent was isolated and Koch's postulates were demonstrated. This is the first record of this fungal disease on Setaria italica.Foxtail millet (Setaria italica (L.) Beauv.) is an important staple food for millions of people in southern Europe and Asia (Reddy et al. 2006). In September and October 2008, plants of S. italica with severe and extensive leaf and sheath spots were found in southern Khorasan, Iran. The spots were oblong to irregularly shaped, varying in size, from 3-20 mm in diameter, dark-brown, with a lighter border and an indistinct margin, sometimes causing leaf veins to rupture (Fig. 1). Severe lodging was observed on chronically infected plants. Symptomatic tissues were excised, surface-sterilised in 0.5% (v/v) sodium hypochlorite solution, placed onto both potato dextrose agar (PDA) and malt extract agar (MEA) each amended with 250 mg/L carbendazim and incubated at 26 C in the dark.Fungal colonies emerging from the tissue had morphological characteristics typical of Bipolaris spp. Colonies were initially white, but after 3 days turned grey to blackish brown, effuse, velvety and black from the reverse side of the Petri dishes on PDA. Conidiophores were septate, solitary, simple or branched, geniculate and sympodial, smooth, reddish brown, 95-205 mm long (average 142 mm), 3-7 mm thick (average 5 mm). Conidia were straight, ellipsoidal or oblong, rounded at the ends, pale brown to reddish brown, mostly three pseudoseptate, mainly 7.5-10.0 Â 15.0-27.5 mm in size. A flattened hilum was seen on the basal cell of the conidia (Fig. 2). On the basis of this morphology and the descriptions by Sivanesan (1987) Pathogenicity tests were performed separately with two single-spore isolates grown for 15 days on Petri dishes containing one-quarter-strength PDA; 30-day-old foxtail millet seedlings were spray-inoculated with a 20 mL conidial suspension (10 5 conidia/mL) plus 0.05% Tween 20, and placed into closed, translucent, plastic bags lined with wet cotton. Plants were incubated at 22-25 C for 48 h after which time the covers were removed. Control plants received only sterile Fig. 1. Leaf-spot symptoms on a foxtail millet leaf.

First Report of Leaf Blight of Jasminum sambac Caused by Bipolaris australiensis in Pakistan

“…and Sorghum halepense (L.) Pers. from Iran (Mirzaee et al, 2010;Ahmadpour et al, 2012), on Cynodon transvaalensis Burtt Daly, and Oryza sativa Linn., from Australia (Sivanesan, 1987;Matsushima, 1989), on Cynodon dactylon-transvaalensis from China (Fang et al, 2007), on Hordeum vulgare L., from Libya (Sivanesan, 1987), on Medicago laciniata (Linn.) Mill., Senecio mesogrammoides O. Hoffm.…”

The Response of Foxtail Millet Candidate Varieties from Nagekeo Regency to Leaf Blight (Bipolaris setariae)

“…Bipolaris setariae can be transmitted through seeds or survived on infected plants residues on the field as a source of inoculums (Das et al 2016;Nasnwa et al 2018). Leaf blight on foxtail millet that can cause economic losses have never been reported in Indonesia, but in 2008 it was reported a severe and widespread attack in Iran's South Khorasa region (Mirzaee et al 2010).…”