Is the presence of Trioza erytreae, vector of huanglongbing disease, endangering the Mediterranean citrus industry? Survey of its population density and geographical spread over the last years

Abstract

Huanglongbing (HLB) is by far the most devastating disease of citrus crops across the world, because it promotes a progressive weakening of citrus trees (until death in around 10 years) that also involves a sudden loss of their production capacity. The African psyllid Trioza erytreae, one of the two known vectors of the bacteria causing HLB, is present in the northwestern Iberian Peninsula since 2014. Since a previous survey done in 2015 showed a considerably spread of this psyllid towards both north and south, a large-scale survey in the subsequent two years was carried out in order to know its current distributional range, population density and, thus the effectiveness of contingency plans. Our results evidence a growing number of new affected areas throughout the Iberian Peninsula, as well as a stronger severity of T. erytreae attacks, which currently occurs from San Xiao (Spain) to Maiorca (Portugal), over 400 km of coastline. The greater ability of T. erytreae to reach new areas may be due to the existence of higher outbreaks and population densities, which represents a serious threat for the nearing citrus-producing areas. If no effective control and management measures are implemented, it seems unavoidable that T. erytreae will spread across Europe.