Agro-ecological factors influencing geographic distribution and epidemic development of hot pepper wilt complex disease in Northwestern Ethiopia

Abstract

Hot pepper (Capsicum annuum L.) production is seriously affected by the wilt complex disease. A study was executed in Northwestern Ethiopia during the 2020 and 2021 main cropping seasons to assess the geographic distribution of the hot pepper wilt complex disease and the association of agro-ecological factors influencing epidemic development. In total, 304 fields were assessed in 11 districts and four zones. The associations among disease variables and biophysical factors were determined using logistic regression analyses. Major pathogens associated with wilt complex disease that exhibited 100% occurrence in all the surveyed districts were Fusarium oxysporum f.sp. capsici, F. solani and Rhizoctonia solani. Out of the 304 hot pepper fields assessed, 233 fields (76.6%) were affected by the wilt complex disease. The highest mean disease incidence (72.4%) and severity (70.1%) were recorded in the Jabi Tehena district, while the lowest incidence (17.1%) and severity (14.9%) were recorded in the Guagusa Shekudad district. District, year, altitude, plant growth stage, weeding frequency, previous crop, wilt management practice, cropping system, and disease-aggravating factor revealed highly significant (p < 0.001) associations with disease incidence and severity. These predictor variables influenced the disease development either positively or negatively in the surveyed areas. The high (≥50%) incidence and severity of wilt complex disease in hot pepper were positively and strongly associated with Bure, Dembecha, Jabi Tehena and Wenberma districts in the 2020 cropping season, where the altitude was <2000 m a.s.l., wilting began at the seedling growth stage, weeding frequency was 1–3 times, and the previous crop was a vegetable. Hence, proper crop husbandry practices and cultural wilt management techniques should be employed by growers to minimize wilt complex disease epidemic development and to sustain hot pepper production and productivity in the survey areas and other locations with similar agro-ecologies.