Relationship between pest and disease incidences and agronomic operations implemented by farmers in cinnamon (<em>Cinnamomum zeylanicum</em> Blume) fields in southern Sri Lanka

Abstract

The national average productivity of cinnamon (Cinnamomum zeylanicum Blume) in Sri Lanka (445 kg/ha) is far below than the attainable yield (1000 kg/ha), which may have an association with pest and disease incidences. Pest and disease incidence was hypothesized to be correlated with awareness of farmers, agronomic practices that implemented in the field, weather parameters, and scale of farming. Hence, better understanding on these relationships is essential for planning a crop management package to increase the cinnamon yield. This study was thus, carried out to investigate the occurrence of pest and disease complex in cinnamon ecosystem, and its’ association with yield level and agronomic practices carried out in cinnamon fields. A detailed field survey was carried out in Galle, Matara, Ratnapura, Kalutara and Hambantota districts of Sri Lanka visiting 260 cinnamon lands during February to May 2013. Information was collected by interviewing the farmers, and making field observations. Significant negative correlations (r = -0.668; p<0.05) were observed between the yield of cinnamon and incidence of wood borer (Ichneumoniptera cinnamomumi;) and rough bark disease (Phomopsis spp.; r = -0.655). Vertebrate pests such as barking deer and peacocks were making a significant damage on the new shoots that appear after harvesting. In addition, ten occasional pest and disease incidences and several minor pest and diseases were observed during the study period. There was a positive correlation between the severity of pest and disease incidence and the overuse of fertilizer and mammoty weeding. A negative correlation was observed between the pest and disease incidence and selective pruning, harvesting in short intervals (4 – 6 months), and slash weeding. Agronomic practices that had negative correlation with pest and disease incidence should be promoted through farmer awareness programmes. The results suggest upgrading the cinnamon crop management package to include these practices.