Pea Leaf Weevil (Coleoptera: Curculionidae) Spatial Distribution in Peas

Abstract

The effects of tillage, location within a plot, and date of sampling on the spatial distribution of adult Sitona lineatus (L.) in peas, Pisum sativum L., were evaluated using geostatistical analyses. The geostatistics procedure uses spatial variation to determine the degree and type of spatial association and dependence of spatially related data. These analyses showed that 88% of the locations sampled had aggregated spatial distribution for adult S. lineatus. The variation that was spatially dependent was only 11.5%. Of the 2 types of aggregated spatial distributions, the spherical spatial distribution was most common on the 1st sampling date under conventional tillage, whereas the check-mark spatial distribution was most common on the 2nd sampling date in the outside edge locations of the pea plots. The smoother soil surface and reduced plant residue of the conventional tillage plot may have increased weevil movement and facilitated aggregation development. The spatial dynamics of this insect changed over time and was probably affected by the physical environment, as represented by the 2 tillage regimes and location within the pea plots. The geostatistical analyses provided insights into the spatial distribution of this insect and potential relationship with agronomic practices.