First report of <i>Alternariaster helianthi</i> causing leaf blight disease of sunflower ( <i>Helianthus annus</i> ) in Sudan

In Sudan, oilseed crops rank second in production area after cereals, and sunflower (Helianthus annuus) is considered a promising (Mohammed, 2010). Leaf blight caused by Alternariaster helianthi destructive disease of sunflower. During autumn 2018 2019 diseased sunflowers with dark brown to black leaves stem spots were observed the Blue Nile state, Sudan. The incidence major rain-fed areas, approximately 690 hectares, was 90 88% 2019, respectively. Symptoms on leaf surface most frequently flowering. appeared form small scattered lamina. irregular, circular 5–10 mm diameter. Later these increased size coalesced covering larger area, margin yellow halo. Necrotic lesions also stem, petioles sepals (Figs. 1, 2) younger plants exhibiting halo (Fig. 3). Infected tissues surface-sterilised sodium hypochlorite (1% v/v) for three minutes, then rinsed times distilled water plated potato dextrose agar. tissue produced olivaceous colonies five seven days. conidia solitary, non-beaked, borne simple unbranched conidiophores, cylindrical elongate elliptic 4). conidium colour subhyaline very dilute tan, becoming slightly darker mature conidia, variable from 18.1 23.9 μm wide 86 112 long, singly conidiophores. Based conidiophore morphology as described Simmons (2007), pathogen identified helianthi. For molecular identification, DNA extracted representative isolate (designated AHE-2) using DNeasy Plant Mini Kit (Qiagen, USA). PCR species-specific primer pair AhN1F/AhN1R (Udayashankar et al., 2012) amplified 314 bp product which sequenced confirmation A. resulting sequence deposited GenBank (Accession No. OM618612). BLASTn analysis showed that had 99% (289/291 bp) identity an rDNA ITS previously (MK968068). Pathogenicity determined inoculating 30 seedlings (30 days old). Conidia one-week-old culture applied 10 ml suspension containing 106 conidia/ml. Twenty control sprayed sterile hand atomiser sprayer. Inoculated covered plastic bags maintained greenhouse 24 hours inoculation. similar those field all inoculated few days, percentage coverage symptoms 38%. re-isolated symptomatic plants, spores isolate. No plants. To our knowledge, this first report has been reported Uganda, Kenya, South Africa (Kgatle 2018; 2019). study, high incidences observed, significant yield losses may occur (Calvet 2005), therefore, management strategies are needed help prevent further spread.