Spatial distribution of avocado branch dieback and wilting (ABDW) vectored by ambrosia beetles in the Caribbean South America

Abstract

Avocado Branch Dieback and Wilting (ABDW) was recently reported on West-Indian avocado (Persea americana var. americana) orchards in the Serrania de Perija, Colombia. This disease is caused by Bionectria pseudochroleuca and transmitted by ambrosia beetles. In this work we estimated the potential distribution of ABDW to map avocado-growing areas at risk of ABDW in Colombia and Venezuela. Disease occurrence records were obtained from pest and disease surveys undertaken during 2014–2015 period in the avocado-growing areas of the Colombian Caribbean. The correlative maximum entropy-based model (MaxEnt) algorithm was used to assess the potential distribution of ABDW in the Caribbean South America. The MaxEnt model predicted locations with potential distribution for ABDW disease in tropical dry forest biomes of Colombia and Venezuela. The largest producing avocado areas in these locations are Serrania de Perija (Colombia) and Serrania de Merida (Venezuela). Field reports from these locations confirm the presence of avocado trees with symptoms of wilting and branch dieback in association with ambrosia beetles. Isothermality, mean diurnal range in temperature and precipitation of the wettest month were the variables with the highest contribution and importance to the spatial distribution model of ABDW disease. A potential distribution map of the ABDW disease for the Caribbean South America was proposed together with an explanatory hypothesis for disease occurrence.