The Delineation of Management Zones of the Halyomorpha halys (Hemiptera: Pentatomidae) Population Based on Its Spatiotemporal Distribution for Precision Agriculture Purposes

Abstract

Precision Agriculture is an agricultural management strategy that aims to increase farmers' profit, maximize crop productivity and sustainability, and protect the environment by applying inputs in optimum rates based on plant needs. The delineation of site-specific management zones is a crucial step at the application of Precision Agriculture. However, the procedure of delineating management zones for pest management is difficult since pest populations are dynamic and change spatially and temporally throughout a growing season. The objectives of this work is to study kiwi canopy characteristics, to correlate them with Halyomorpha halys (Hemiptera: Pentatomidae) populations and delineate management zones for pesticide applications in variable rates. To achieve this, four kiwi orchards in total were selected in the regions of Pieria and Imathia in Greece. Τen traps were installed from early May to late October within each selected kiwi orchard: two types of traps at every side of the orchards and the center. The installed traps were examined weekly, and the number of the captured H. halys was recorded. During the same days, sentinel satellite images were analyzed to calculate the indices: NDVI (Normalized Difference Vegetation Index) and NDWI (Normalized Difference Water Index). The collected data were combined in a GIS software to delineate management zones using a K means algorithm and unsupervised classification. The results of this three-year study showed population variability within the kiwi orchards since the population of H. halys was higher in field regions where NDVI and NDWI values were high. The delineation of management zones revealed that there are spatio-temporal stable zones in each field where there is high, medium, and low risk to develop H. halys populations. The benefits of the proposed strategy are multiple since it is expected that farmers will be able to reduce the production expenses of kiwifruits and environmental protection while increasing profit.

Keywords: brown marmorated stink bug; kiwifruit; pesticide; remote sensing; site-specific management; variable rate application.

Figure 1

Kiwi orchards at different regions in Greece. Every orchard was equipped with two different types of traps at five sites. Red dots represent the exact positions where traps were installed.

Figure 2

NDVI, NDWI, and H. halys spatial variability over three years of study for each season and fields based on adult and nymph captures. Green maps represent the NDVI variability. The brighter the green, the higher the NDVI values. The lowest NDVI is 0.62, and the highest is 0.95. Blue maps represent the NDWI variability. The darker the blue, the higher the moisture at the canopy and the opposite. The lowest NDWI value is −0.2, and the highest is 0.1. The yellow circles with red outlines show the exact site of the traps installed. The size of the yellow circles represents the size of the H. halys population. The bigger the circle, the bigger the population. The classification method for NDVI and NDWI data is the quantile.

Figure 2

NDVI, NDWI, and H. halys spatial variability over three years of study for each season and fields based on adult and nymph captures. Green maps represent the NDVI variability. The brighter the green, the higher the NDVI values. The lowest NDVI is 0.62, and the highest is 0.95. Blue maps represent the NDWI variability. The darker the blue, the higher the moisture at the canopy and the opposite. The lowest NDWI value is −0.2, and the highest is 0.1. The yellow circles with red outlines show the exact site of the traps installed. The size of the yellow circles represents the size of the H. halys population. The bigger the circle, the bigger the population. The classification method for NDVI and NDWI data is the quantile.

Figure 2

NDVI, NDWI, and H. halys spatial variability over three years of study for each season and fields based on adult and nymph captures. Green maps represent the NDVI variability. The brighter the green, the higher the NDVI values. The lowest NDVI is 0.62, and the highest is 0.95. Blue maps represent the NDWI variability. The darker the blue, the higher the moisture at the canopy and the opposite. The lowest NDWI value is −0.2, and the highest is 0.1. The yellow circles with red outlines show the exact site of the traps installed. The size of the yellow circles represents the size of the H. halys population. The bigger the circle, the bigger the population. The classification method for NDVI and NDWI data is the quantile.

Figure 3

Spatial temporal management zones in each season for each field separately. Areas with green color are high-risk areas where H. halys could develop populations. On the other hand, the yellow color represents areas where there is medium risk to develop H. halys populations, and the red color shows the low-risk areas.

Figure 3

Spatial temporal management zones in each season for each field separately. Areas with green color are high-risk areas where H. halys could develop populations. On the other hand, the yellow color represents areas where there is medium risk to develop H. halys populations, and the red color shows the low-risk areas.