The new combination Lecanosticta acicola received the general acceptance of plant pathologists and mycologists ( Sutton, 1980 Arx, 1983) for the anamorph of the brown-spot fungus. Later ( Sydow and Petrak 1924), he recognised the synonymy but considered that the generic concept of Lecanosticta was still valid because of the erumpent stromata and darkly pigmented conidia. He named the fungus Lecanosticta pini being unaware that there were earlier descriptions. Sydow ( Sydow and Petrak, 1922) received Pinus taeda material with needle blight and erected the new genus Lecanosticta. But this genus was characterised by hyaline, aseptate conidia so that Saccardo (1884) moved the species on account of its septate conidia to the genus Septoria. The causal agent in the form of the anamorphic state was first described by De Thümen (1878) as Cryptosporium acicola. The brown spot disease has been known in the southern USA since the nineteenth century ( Hedgcock, 1929). Plant disease reports from the EPPO region also suggest an increase in the prevalence in that part of the world. dearnessii has spread rapidly and has a very wide distribution.
In Christmas tree plantations attack of brown-spot needle blight on Scots pine and other pines results in the loss of thousands of dollars, because of needle drop, making the trees unmerchantable ( Phelps et al., 1978). The impact of brown-spot disease on longleaf pine results in the reduction of total annual growth by more than 16 million cubic feet (453 thousand cubic metres) of timber. Long known as a serious disease in longleaf pine in the Gulf States of the USA, the pathogen gained added notoriety in recent decades because of needle browning and defoliation of landscape and Christmas tree plantings of ponderosa and Scots pines in the central plains and Great Lakes regions ( Phelps et al., 1978 Sinclair et al., 1987). The brown-spot fungus mainly attacks pines from Central to North America but also in localities from South America, Asia, Africa and Europe. The pathogen has a wide host and habitat range and occurs on pines in tropical to temperate zones. Brown-spot needle blight caused by Mycosphaerella dearnessii kills foliage and retards growth of many pine species.
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