Farmers Perceptions on the Causes and Effects of Cassava Witches’ Broom (CWB) on Cassava Production in Three Provinces of Cambodia

Abstract

Cassava production in Cambodia has been increasing due to favorable market and agro-ecological conditions. However, damage to cassava crops by pests is posing significant concerns, due to the impact on yield and starch quality. Among the most important diseases is Cassava Witches’ Broom (CWB), that has only recently been identified in Cambodia which is increasing in severity, and for which there are limited control. A survey on causes and effects of CWB was undertaken in 2015 with 150 cassava growers in the three provinces of Kampong Cham, Prey Veng and Svay Rieng. A further 30 cassava farmers participated in a focus group discussion. The main objectives of this study were to get an understanding of the current level of damage caused by CWB on cassava production, the causes of the disease, and the control measures taken by the respondents in relation to the disease. CWB is perceived by cassava growers as the most serious disease in their cassava crops, potentially causing more than 50% decline in tuber yields (from an average of about 19.5 t/ha in a normal year, to 8.5 t/ha in a year of CWB infection and damage). From the perceptions of respondents, four reasons were given for the incidence and damage of CWB. These included, poor soil fertility (28.70%), drought (28%), the side effects of pesticide use (20%), and the quality of planting materials/varieties planted (18%). Even though these are the reasons provided by cassava farmers, they do not have the capacity to control the disease, despite the following initiatives: pesticide application (55%), change to CWB resistant varieties (15%). Farmers reported that pesticide application is not an effective strategy to control CWB, and recommended that improved agricultural extension services could help them get access to CWB resistant varieties, as well as to address other production issues, in a timely manner.