Spatial and Temporal Spread Patterns of Viral Diseases on a Zucchini Squash Field in the Coastal Savannah Zone of Ghana

Abstract

A B S T R A C T Mathematical models play crucial role in effective plant disease management. They permit accurate forecasting of plant disease epidemics for timely interventions. However, the use of mathematical models in plant disease management has not received much attention in Ghana. This study assesses the disease intensities and the spatio-temporal spread patterns of viral diseases on a zucchini squash (Cucurbita pepo L.) field in the coastal savannah zone of Ghana. Disease intensity data were transformed by Exponential, Monomolecular, Gompertz and Logistic models. Semivariance analysis and Inverse Distance Weighting interpolations were performed using the GS+geostatistical software. The Gompertz model explained best the observed variability in disease incidence data with 90.86% agreement between field-observed and model-predicted disease incidence data. For disease severity, the Exponential model best described the progress of the disease with a co-efficient of determination of 94.38%. The semivariogram estimated a range of spatial dependence of 0.63 m and a sill of 1.91400.