Validation of a geographic weighted regression analysis as a tool for area-wide integrated pest management programs for Ceratitis capitata Wiedemann (Diptera: Tephritidae) on Terceira Island, Azores

Abstract

Extrapolation from quantitative sampling to the surrounding areas is an essential feature of many aspects of real world applications in pest management decision making. However, these decisions are only as good as the accuracy of the methods that provided the information. The problem of estimating Mediterranean fruit fly population densities from trap grids is a specific case.The efficiency of three methods to estimate fruit flies trapped per day (FTD) values for non-sampled areas in Terceira Island is evaluated, the Inverse Distance Weighted (IDW), Ordinary Kriging (OK) and the Geographic Weighted Regression (GWR). Each method has its own specificities and merits.The results demonstrate that the GWR method is capable of estimating hotspots for the next season and can be used to identify ecological corridors over a non-sampled area. The high spatial heterogeneity and topographical conditions present on Terceira Island may explain why a more mathematically complex method is more reliable than simpler methods for use in possible future wide-area control program for Medfly.

Seasonality of the Mediterranean Fruit Fly (Diptera: Tephritidae) on Terceira and Sao Jorge Islands, Azores, Portugal

“…These studies are carried out using trapping systems to estimate the presence, seasonal abundance and spatial distribution of adults to make predictions of fruit host infestation levels (Díaz-Fleischer et al 2014). This information, combined with Geographic Information Systems (GIS), allows the identification of critical periods and key locations as targets for application of area-wide suppression techniques that impact pest populations at the landscape level in their most vulnerable stage (Pimentel et al 2005, 2014b; Lopes et al 2006b,c; Vreysen et al 2007; Capinera 2008; Aluja and Rull 2009; Midgarden et al 2014). Moreover, the development and use of biologically based pest management tactics, such as use of natural enemies or sterile insect technique (SIT), requires a detailed knowledge of pest biology and ecology, including life cycle, population dynamics, and interactions with the physical and biological environment, including potential competitors, predators and parasites (Capinera 2008).…”

“…Within the activities and objectives of the research projects (MAC/3.1/A1) Interfruta (2004–2006), (MAC/3.1/A4) Interfruta II (2006–2009), some studies about C. capitata including high density locations, dispersion and fruit infestation have been carried out (Pimentel et al 2005, 2014b; Lopes et al 2006b,c; Pimentel 2010). One of the main goals of the first Interfruta project was to attend the concerns of growers, farmers, and technicians about this pest.…”

“…One of the main goals of the first Interfruta project was to attend the concerns of growers, farmers, and technicians about this pest. Therefore, the first studies were made to evaluate what was the best trapping system (Nunes et al 2005) and which orchards was this insect mainly located (Pimentel et al 2005). Another goal was to evaluate the sexual (Costa 2007) and dispersion fitness of the sterile males, produced in Madeira’s Biofactory, under Terceira’s conditions (Lopes et al 2005).…”

“…The second Interfruta project was aimed, more specifically, to an area-wide approach of this pest as it provided the opportunity to install and monitor a network of traps all around the Terceira Island from the 0 to 200 m of altitude (Lopes et al 2009, Pimentel 2010). This study provided a better knowledge of spatial distribution of Medfly over Terceira Island, as it unveiled the ecological corridors and the main hotspots over time.…”

“…Medfly was first reported in the Azorean Archipelago in 1829, coincident with the establishment of orange production (Quaintance 1912). Nowadays, according to Lopes et al (2006c) and Pimentel (2010), Medfly on Terceira Island, prefers other fruits over oranges. This change in fruit host preferences, along with changes in the extent and pattern of horticultural production over the years, shows the biological adaptability of this insect to environmental changes, such as fruit availability.…”