Use of geostatistical analysis to characterize the spatial distribution of Lobesia botrana (Lepidoptera: Tortricidae) larvae in northern Greece

Gaining a better understanding of the spatial variation of pests is a key to their more effective mapping to improve our knowledge of their overall population dynamics and optimize our control strategies. Geostatistical methods were used in this study to characterize spatial variability in Lobesia botrana Denis and Schiffermuller (Lepidoptera: Tortricidae) larval infestation, injury, and damage patterns in six locations over 2 yr. Regression was used to detect and separate macroscale trends from the microscale variation. The presence of macroscale variation indicated a significant edge effect with insect population moving into vineyards and ovipositing mainly along the field edges. Similarities in the patterns of spatial variability occur between the second and third generations and also between infestation, injury, and damage in all fields. The microscale variation was studied using semivariograms for all fields. Semivariograms strongly indicate that the spatial structures of L. botrana larvae were aggregated with dependency down a row of vineyards differing from that across rows of the crop, leading to anisotropy. The average range across the vine rows was consistently shorter than along rows, suggesting that migration occurs more easily down rows than across them. The anisotropic analysis further indicates that sampling programs can deploy sample locations at greater distances along the rows than across them, and interpolation algorithms that use this information may produce better map estimates. These results have implications for developing sampling plans for management of L. botrana and for site-specific agriculture.