Modeling the physiological timing of Ceratitis capitata through remote sensing in strategic territories in Central America

Abstract

The Mediterranean fly is a quarantine pest that can directly affect the production and marketing of fruits and vegetables worldwide. It is a species with polyphagous behavior and has a high number of susceptible hosts, both wild and economically important. Currently, in Central America and Southern Mexico, there are strategic territories with permanent monitoring of the pest, which act as barriers in its advance towards North America. The use of remote sensors in the phytosanitary area has the potential to contribute to decision-making in the establishment of preventive strategies to mitigate the advance and phytosanitary risk of Ceratitis capitata. It can even be considered a geotechnological tool that contributes to the processes of monitoring and surveillance of health risks, through the analysis of environmental information, particularly the thermal component. Temperature is an essential factor for the immature and adult stages of the Medfly. The objective of this study was to design the physiological time of C. capitata through the calculation of accumulated heat units (UCAcum) in strategic territories. Specifically, the study aimed to model and calculate the physiological time of C. capitata through the accumulated heat units (UCAcum) in the potential containment, containment, and eradication zones using ERA5 data.

A spatiotemporal pattern was obtained for the period from December 2020 to December 2021, showing the monthly thermal behavior that favors C. capitata on two scales: a regional scale that included the countries of El Salvador, Honduras, Guatemala, and southern Mexico, and the previously defined strategic zones.

The study revealed a monthly thermal oscillation from 13,1 to 37,4°C, considering extreme temperatures. The surfaces with optimal thermal accumulation, determining the physiological time of the pest, were identified based on the fact that C. capitata requires 251,7 UCAcum to complete a life cycle. In the potential containment zone, 463,4 UCAcum were determined for portions of Honduras and El Salvador. In the containment zone in Guatemala, 418,8 UCAcum were identified, and finally, in the eradication zone, an accumulation of 401.3 units was observed in Guatemala and the Pacific coast in the Mexican southeast. This spatial analysis showed that the physiological time presented a uniform behavior in strategic territories.

Modeling UCAcum from remote sensing strengthens strategic decision-making regarding health risks. The strength of this approach lies in the accessibility of freely available inputs and recent temporality, allowing the creation of risk scenarios under a preventive approach in almost real-time (with a three-week delay). Thermal comfort modeling should be considered a contributing input to effectively direct preventive strategies by the National and Regional Plant Protection Organizations. These organizations are responsible for implementing mitigation strategies before the arrival of pests or diseases that endanger the global agro alimentary heritage.