Fig 1.
Location of the study area within the Ugandan Mount Elgon area and the districts of the study area (Bulambuli, Kapchorwa and Sironko) with indicated sub counties and three altitude ranges determined by means of a cluster analysis.
Fig 2.
Methodological framework of the study.
Comparison between FPK, expert knowledge and field observations with regard to a selection of variables related to CPaD and along a gradient of altitude and production system. Horizontal dashed arrows indicate between which levels (Farmers, Experts, Field) the variables have been compared to. Roman and Arabic numerals correspond to collection and analysis of data as described in the subsequent sections. (i) Farmer survey, (ii) Expert workshop, (iii) Pest and disease field assessments, 1-7 correspond to the sequence of questions asked to farmers shown in Table 1.
Table 1.
List of questions posed to the farmers.
Table 2.
List of Coffee pests and diseases (CPaD) used in interview survey.
Table 3.
Characteristics of production typologies generated by K-means Clustering.
Fig 3.
CPaD occurrence perceived by farmers.
Proportion of farmers who reported CPaD to be present to farmers where CPaD were not present per altitude range. Low altitude n = 57; Mid altitude n = 41; High altitude n = 50. Fishers’ exact test (* significant at p < 0.05; ** significant at p < 0.005; *** significant at p < 0.0001).
Table 4.
Comparison of perceived impact scores between altitude ranges.
Table 5.
Farmers’ CPaD management practices.
Table 6.
CPaD control practices proposed by experts.
Table 7.
Quasi-binomial model results examining individual and interaction effects of altitude range and production system on WCSB incidence.
Fig 4.
Interaction plots of the least-squares means (back-transformed by inverse-link function to original response scale) based on the fitted models.
Effect of coffee production systems on predicted probability of WCSB incidence (A) and predicted number of lost berries due to CBD (B) at different altitude ranges. Production systems with the same letter do not differ significantly (Tukey-type comparisons of glm-parameters, p < 0.05, tested separately for each altitude range). An interaction is given if the difference between coffee systems of one altitude range differs significantly from the difference between coffee systems of another altitude range. CB = Coffee-Banana System, CO = Coffee-Open System, CT = Coffee-Tree System.
Table 8.
Negative-binomial model results examining individual and interaction effects of altitude range and production system on CBD intensity.