Cassava mosaic disease (CMD) is the main threat to cassava (Manihot esculenta Crantz) production in Benin. This study was conducted to assess CMD incidence, disease severity, and adult whitefly (Bemisia tabaci) populations in 11 regions of Benin. A total of 180 cassava fields across the country were assessed during June–December 2020 following the harmonized protocol of the Central and West African Virus Epidemiology program. Based on symptoms observation, CMD was present in all surveyed fields in Ouémé and Alibori regions. The highest disease incidence levels were observed in Malanville (100%), Kpomassè (86.67%), Kandi and Zagnanado (both 81.67%), Ségbanan (80%), and Avrankou (76.67%) districts. The highest mean severity scores were in Couffo (3.68), Mono (3.63), and Atlantique (3.33) regions, while the lowest was in Alibori (2.37). Adult whitefly populations (mean number/plant) were highest in Couffo (15.88) and Mono (13.00) regions and lowest in Donga (0.06). Significant relationships were found between CMD severity and whitefly abundance (P = 0.0010) but there was no significant relationship between whitefly numbers and CMD incidence (P = 0.0577). These findings indicate that CMD has expanded its range across Benin. They also provide a basis for designing a response strategy for the control of cassava virus diseases such as CMD.

木薯花叶病（CMD）是贝宁木薯（ Manihot esculenta Crantz）生产的主要威胁。本研究旨在评估贝宁 11 个地区的 CMD 发病率、疾病严重程度和粉虱成虫 ( Bemisia tabaci ) 种群。 2020 年 6 月至 12 月期间，根据中非和西非病毒流行病学计划的统一方案，对全国共 180 个木薯田进行了评估。根据症状观察，韦梅和阿里博里地区的所有调查田地均存在 CMD。发病率最高的是马朗维尔 (100%)、科波马塞 (86.67%)、坎迪和扎尼亚纳多 (均为 81.67%)、塞格巴南 (80%) 和阿夫兰库 (76.67%) 地区。平均严重程度得分最高的是库福 (3.68)、莫诺 (3.63) 和大西洋 (3.33) 地区，而最低的是阿利博里 (2.37)。粉虱成虫数量（平均数量/株）在库福 (15.88) 和莫诺 (13.00) 地区最高，在东加 (0.06) 最低。 CMD 严重程度与粉虱丰度之间存在显着关系（ P = 0.0010 ），但粉虱数量与 CMD 发病率之间没有显着关系（ P = 0.0577 ）。这些发现表明 CMD 已将其范围扩大到整个贝宁。它们还为设计控制 CMD 等木薯病毒病的应对策略提供了基础。