Spatial and temporal spread of maize stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) damage in smallholder farms

- A new sampling scheme for damages of Busseola fusca in a maize fram.
- Identification of spatial and temporal patterns of Busseola fusca damage spread in a maize farm.
- Advanced analysis of pest and diseases spread.

The main purpose of this study was to understand the spatio-temporal spread of the maize stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) in smallholder maize farms. The analysis carried out allowed the establishment of complementary sampling scheme and analysis that can be applied to investigate the propagation of stem borer damages and extended to other insect pests. This approach requires consideration of all plants point locations, the knowledge on the level of damage and its characterization. Results showed that there was a two-week interval between occurrence of the peaks of leaf damage and male adult moth abundance. The prior role of leaf damages in the farm infestation by B. fusca is revealed, and an estimate of the mean transition time between different damage types is provided. Furthermore, damaged plants exhibited a local spatial autocorrelation within a range of dependence of 0-10 meters; and the spatio-temporal pattern of B. fusca damage spread evolves as a spiral around an initial patch of damaged plants. By assuming a neighbor configuration of distribution of damaged plants nearby non-damaged, we showed that the inner plants are likely to become damaged within a time period of a week; thus, B. fusca infests farms in a systematic fashion. Overall, these results have useful implications for improving and optimizing existing field sampling methods for insect pest damages. The approaches used in carrying out the analysis further provided a deep understanding helpful to improve integrated pest management (IPM) strategies against stem borers, and offer IPM practitioners' the opportunity to design, develop, and implement optimum control methods against B. fusca, an important pest of maize in Africa.