The effect of spatial variation for predicting aphid epidemics

Abstract

9In order to improve forecasting of aphid epidemics, it is important to know the spatial scale at which 10 specific forecasts are reliable. To investigate the spatial scale of aphid epidemics, we have developed a 11 spatio-temporal stochastic aphid population growth model, and fitted the model to empirical spatial time-12 series aphid population data using a Bayesian hierarchical fitting procedure. Furthermore, detailed spatial 13 data of the initial phases of epidemic development was investigated in a semivariogram. Our results 14 suggest that there is limited spatial variation in the initial occurrence probability at a spatial scale of 10 km. 15Consequently, the results support the hypothesis that initial aphid population sizes and epidemics may be 16 predicted in fields within a 10 km radius. For farmers, this may imply that they can rely their decision of 17 whether to spray against aphids on observations made by other nearby farmers or by the consultancy 18 service. 19

Spatio-temporal variations in wheat aphid populations and their natural enemies in four agro-ecological zones of Pakistan

“…Understanding spatial variability of aphids in wheat agro-ecosystems using certain models can potentially facilitate site specific application of pesticides, decreasing the amount and cost of pesticides, environmental pollution and pesticide exposure to farmers while increasing the biological control agents [49]. A recent preliminary study suggests that forecasting of aphid epidemics can be more reliable within the radius of only 10 km [50]. However, landscape scale studies can create or improve pest monitoring procedure and pesticide application programs at regional level [36].…”