Incidence and Growth Effects of Striga Hermonthica Infestation on Sorghum Bicolor Farms in Adamawa State, Northeastern Nigeria

Striga hermonthica is an economically important parasitic weed that constrains cereal production in sub-Saharan Africa, including northern Nigeria. This study assessed the incidence, infestation density and growth effects of S. hermonthica on Sorghum bicolor farms in selected locations of Adamawa State, Nigeria, during the 2024 and 2025 rainy seasons. A systematic field survey was conducted in eight locations distributed across Fufore, Girei, Shelleng and Mubi North Local Government Areas. Three sorghum farms were randomly selected from each location, giving a total of 24 farms. Within each farm, three 10 m × 10 m quadrats were randomly established for assessment. The number of healthy and Striga-infested sorghum stands, number and height of emerged S. hermonthica plants, and height and width of healthy and infested sorghum plants were recorded. Striga incidence was expressed as the percentage of sorghum stands infested by the parasite, while percentage reduction in sorghum height and width was used to estimate growth effects. Data were subjected to analysis of variance, and means were separated using Duncan's multiple range test at p ≤ 0.05. Striga hermonthica occurred in all surveyed locations, with incidence ranging from 20.99% to 59.42% in 2024 and from 21.62% to 53.23% in 2025. The pooled incidence was highest at Fufore-Pariya (54.41%) and lowest at Mubi-Muchala (21.23%). The highest pooled Striga population was also recorded at Fufore-Pariya (65.50 plants), whereas Mubi-Muchala recorded the lowest (17.66 plants). Infestation was associated with substantial reductions in sorghum growth. Pooled reduction in plant height ranged from 32.97% at Mubi-Betso to 63.14% at Girei-Town, while reduction in plant width ranged from 47.60% at Girei-Town to 58.03% at Mubi-Betso. The findings demonstrate that S. hermonthica is widely distributed in the surveyed sorghum-producing areas of Adamawa State and is associated with considerable suppression of sorghum growth. The information provides a basis for targeted surveillance and integrated management of S. hermonthica in affected sorghum-growing communities.