Lecanosticta acicola: A growing threat to expanding global pine forests and plantations

Abstract

Summary Lecanosticta acicola causes brown spot needle blight (BSNB) of Pinus species. The pathogen occurs mostly in the Northern Hemisphere but has also been reported in Central America and Colombia. BSNB can lead to stunted growth and tree mortality, and has resulted in severe damage to pine plantations in the past. There have been increasingly frequent new reports of this pathogen in Europe and in North America during the course of the past 10 years. This is despite the fact that quarantine practices and eradication protocols are in place to prevent its spread. Taxonomy Kingdom Fungi; Phylum Ascomycota; Subphylum Pezizomycotina; Class Dothideomycetes; Subclass Dothideomycetidae; Order Capniodales; Family Mycosphaerellaceae; Genus Lecanosticta. Host range and distribution Lecanosticta spp. occur on various Pinus species and are found in North America, Central America, South America (Colombia), Europe as well as Asia. Disease symptoms Small yellow irregular spots appear on the infected pine needles that become brown over time. They can be surrounded by a yellow halo. These characteristic brown spots develop to form narrow brown bands that result in needle death from the tips down to the point of infection. Needles are prematurely shed, leaving bare branches with tufts of new needles at the branch tips. Infection is usually most severe in the lower parts of the trees and progresses upwards into the canopies. Useful websites The EPPO global database providing information on L. acicola (https://gd.eppo.int/taxon/SCIRAC) Reference genome of L. acicola available on GenBank (https://www.ncbi.nlm.nih.gov/genome/?term=Lecanosticta+acicola) JGI Gold Genome database information sheet of L. acicola sequenced genome (https://gold.jgi.doe.gov/organism?xml:id=Go0047147)

Spread of the invasive pathogen Lecanosticta acicola on species of Pinus in Bulgaria

“…in recent years. It is the only species in the genus known to be a significant pathogen that is spreading rapidly in Europe and in the north-eastern parts of North America (van der Nest et al, 2019). In Bulgaria, the pathogen was reported for the first time in 2017 in a generative plantation of P. sylvestris in the region of SF Ardino, the Eastern Rhodopes (Stamenova et al, 2018).…”

New Hosts for Lecanosticta acicola and Dothistroma septosporum in Spain

“…None of the tested samples yielded a positive result for D. pini or Phytophthora sp. [2,5,6]. Pinus brutia is a pine species closely related to P. halepensis…”

“…The presence of L. acicola and Dothistoma spp. has been detected on 53 and 96 different Pinus species, including hybrids, respectively [2,5,6]. At least two putative introductions of L. acicola have occurred in Europe from North America [7].…”

First molecular detection of Lecanosticta acicola from Poland on Pinus mugo

“…Lecanosticta acicola , which originates in North America (Van Der Nest, Wingfield, Ortiz, & Barnes, 2019b), was first recorded in Europe Spain in the 1940s and, since then, had been found in many countries of Europe: Italy, France, Germany, Austria, Switzerland, Slovenia, Czech Republic, Spain, Croatia, Sweden, Estonia, Lithuania, Latvia, Ireland, Portugal and Russia (Janoušek et al, 2016; Mullett et al, 2018; Van Der Nest et al, 2019a). Previously, only one report of L. acicola on Pinus mugo from the southern part of Poland based exceptionally on morphological identification has been published (Pusz, 2014).…”

“…Lecanosticta acicola (Thümen) H. Sydow is the causal agent of brown spot needle blight (BSNB), known to affect 53 Pinus species (Van Der Nest, Wingfield, Janoušek, & Barnes, 2019a). First symptoms of brown spot needle blight disease on infected needles usually appear as resin‐soaked, yellowish lesions, with a clear orange border.…”