Demographic characteristics, incidence and severity of onion basal rot in the Upper East Region of Ghana

Onion basal rot poses a serious threat to onion production in the Upper East Region of Ghana. A survey was conducted in 2022 in three purposefully sampled districts and a municipality in the region to determine the incidence and severity of the disease and to assess the perception and knowledge of farmers on the spread and control of the disease in the Region. In each district/municipality, three communities were purposefully selected for the study. A questionnaire was administered to 180 onion farmers randomly selected to assess the farmers' perceptions, knowledge, and agronomic practices. Fifteen onion fields, from each district/municipality, were randomly selected for the assessment of the incidence and severity of the disease. Symptomatic onion plants were collected for pathogen isolation using potato dextrose agar. The causal organism was identified as Fusarium oxysporum f. sp. cepae based on morphological characteristics and confirmed by pathogenicity test. Under irrigated conditions, the incidence of onion bulb rot was highest in Bansi (28.92%) and lowest in Kuka (19.47%). The disease severity index, on the other hand, was highest and lowest at Yalugu (44.25%) and Bugri Corner (30.15%), respectively. The disease incidence was significantly higher in the rainy season than in the dry season.