Agronomic practices preventing local outbreaks of rice yellow mottle virus disease revealed by spatial autoregressive analysis

Abstract Rice yellow mottle virus (RYMV) causes severe rice ( Oryza sativa L.) yield loss. It has been endemic to sub-Saharan Africa and Madagascar since 1966. Transmission (plant community level) long-dispersal (regional continental scale) models have established but viral spread in farming communities continues, while the conditions causing local disease outbreaks remain unclear. We hypothesized that outbreaks, comprising inter-plot intra-plot aggravation, are significantly associated with individual farmers’ attributes agronomic practices. To test this hypothesis, spatial autoregressive were constructed using variables collected by visual observation farmer interviews. Field surveys conducted during four consecutive cropping seasons from 2011 2013 Lower Moshi Irrigation Scheme of Kilimanjaro, Tanzania. Our detected dependence spread, not aggravation. The probability increased use IR64 cultivar (26.9%), decreased straw removal (27.8%) crop rotation (47.7%). aggravation herbicide application (24.3%) (35.4%). A simple cost-benefit analysis suggested should be mitigated replacement removal. When severity is critical, inhibited application, rotated other crops. This first study upscale model experimental field level level, obtaining through easy-to-implement techniques such as interview. successfully identified candidate practices for control RYMV. However, causal relationships between RYMV unknown, trials needed develop robust measures.