Potential Risk Levels of Invasive Fire Blight in Apple Orchards Around the World

R. S. Ramos,P. T. D. de Borba,R. D. A. Vieira,J. Ebel,R. S. da Silva,L. Zambolim

doi:10.5539/jas.v12n11p17

Abstract

Fire blight, a disease of apple trees caused by Erwinia amylovora, occurs worldwide except in South America, South-Central Africa, and most of Oceania. Ecological niche models can determine the potential distribution of species and measure the risk of pest invasion. This study aims to develop global climate suitability models using MaxEnt software for E. amylovora and to determine the regions in which apple cultivation and the bacterium are most likely to co-occur. Most occurrence data for E. amylovora (93%) are from the northern hemisphere, distributed between 63.90 to 14.56 degree days in regions of Africa, Central America, North America, Asia, and Europe. The only country in the southern hemisphere that this bacteria has been detected is New Zealand (Oceania). Apples are cultivated on every continent except Antarctica, between 61.55 to 44.41 degree days. We find that regions of South-Eastern Africa, Argentina, Australia, Southern Brazil, Bolivia, Chile, China, the United States, Madagascar, Morocco, Mexico, New Zealand, Peru, Tunisia, Uruguay, and the majority of Europe are suitable for both E. amylovora and apple cultivation. These results provide information on the potential worldwide distribution of E. amylovora in apple production area.

Highlights

Erwinia amylovora (Burrill, 1882) Winslow et al (1920) causes fire blight, a pathogen that affects the apple tree Malus domestica Borkh
After spatial filtering to reduce the autocorrelation in the occurrence records, our dataset was comprised of a total of 254 and 293 occurrence points of E. amylovora and M. domestica, respectively
The current known distribution of E. amylovora is in temperate regions of the northern hemisphere, in North and Central America, Europe, Asia, Africa, and some areas of Oceania

Summary

Introduction

Erwinia amylovora (Burrill, 1882) Winslow et al (1920) causes fire blight, a pathogen that affects the apple tree Malus domestica Borkh It is the most severe pathogen affecting this crop, threatening the production in areas where it is present (EPPO, 2004). First described in the New York State, United States, in 1780, the disease later spread to the east and west coasts of this country and regions of Canada (Palacio Bielsa & Cambra Alvarez, 2009) It is present in almost all continents, with recorded observations in North and Central America, Africa, Europe, Asia, and Oceania, though with no records in South America (European and Mediterranean Plant Protection Organization - EPPO) (2019). 200 ha of orchards were eradicated in Morocco between 2006 and 2010, resulting in losses of around EUR 55 million (Fatmi, 2011)

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