Potential distribution of Melanagromyza sojae in South America and current situation in Argentina

Abstract

The Asian soybean stem borer Melanagromyza sojae (Zehntner) (Diptera: Agromyzidae) represents a threat to soybean and chickpea crops in South America. It is known that in the region its population has increased, in part, due to the difficulty in its agronomic management. This is due to the lack of knowledge regarding its biology and the environments that are favorable for its establishment. In this study, we provide a comprehensive database of records of M. sojae, as well as an updated list of its host plants from field surveys, bibliographic review, and online databases. We estimated the suitability and potential distribution of the pest considering environmental information from remote sensors and bioclimatic variables and contrasted these against land-use cover across South America. In Argentina, M. sojae was found developing on Tithonia tubaeformis (Jacq.) Cass. (Asteraceae), surviving in chickpeas and volunteer soybeans that were affected by winter frost. The most informative models and highest suitability were predicted from vegetation indices and bioclimatic variables, and coincided with sites having a high proportion of arable land. Regarding climate, the greatest suitability occurred in eastern South America, including the southern states of Brazil and Paraguay, where the final models recovered the current known distribution of the species on the continent. However, its extension may be even greater than predicted, due to the wide distribution range of its hosts. This characterization of suitability for M. sojae could be a useful resource to anticipate the regions that are most favorable for its presence and supports the need to consider the distribution of crops and host plants that could act as natural reservoirs to identify sites and streamline efforts to reduce the incidence of the pest.