Epsilon Archive for Student Projects

Abstract

The coffee industry in Uganda plays a critical role contributing to its export earnings. However, it is
severely affected by a biotic stressor, the Black Coffee Twig Borer (BCTB), causing unstable income due to BCTB-infested yield loss in smallholder farms. The Ugandan smallholder coffee farmers face challenges to control the BCTB due to some knowledge gaps such as limited understanding of BCTB biological behavior and environmental triggers of infestations. The field trial employed a push-pull management strategy, i.e a combination of repellents and attractants in search of a sustainable solution.
This was combined with a semi-structured interview and an online survey to draw a full picture of the situation. In eight plots in Kamuli district of Uganda, two repellent treatments i.e. verbenone (T1) and synergy of verbenone and methyl salicylate (T2) were applied in a slow release device and infestation was monitored. Both treatments decreased the total number of infested twigs and total number of new entry
holes at early stages, with T2 showing a more profound effect. T1 and T2 also lowered the number of borers captured by attractant traps as compared to control. However, the effectiveness of both repellents decreased over time. Interestingly, a significant positive relationship was found between shade level and infestation rate under control and T1, also confirmed farmers’ answer in the survey and interview, stating that a higher shade level might contribute to a more severe BCTB infestation. No correlation was,however, found under T2, which may indicate that repellency of BCTB may disrupt the otherwise clear effect of shade on infestation levels. Farmers commonly practiced intercropping in their coffee farms for varying purposes. However, they lacked the knowledge of selecting the best intercrops to avoid elevating the BCTB infestation rate. Additionally, the interview showed good awareness of farmers of the BCTB problem, but poor ability to identify and cope with it. Removing infested material such as twigs and plants
and burning them are known to be an effective way to control BCTC infestation level, but it is hard for coffee farmers to manage to do it due to labor intensive work. The interview also identified a large gap of perception between farmers and extension officers about the accessibility and quality of the services. This results that extensions services are nor fully capable of serving the needs of the farmers, and that communication can be improved. This thesis work aims to examine the effectiveness of the two types of repellents on mitigating BCTB infestation based on data acquired from local Ugandan-farm-grown coffee trees. This work was also designed to update the local people’s perception on BCTB management. The research can be further deepened to more detailed research on the mechanisms behind the repellents. The information extracted from the interview depicts the unstable coffee cultivation system in Uganda, highlighting the need for a more effective extension service system in the future.