Spruce budworm

Spruce budworms and relatives are a group of closely related insects in the genus Choristoneura. Most are serious pests of conifers, such as spruce. There are nearly forty Choristoneura species, and even more subspecies, or forms, with a complexity of variation among populations found throughout much of the United States and Canada, and about again this number in Eurasia. In Eastern North America, Choristoneura fumiferana is prevalent, while in Western North America Choristoneura freemani has devastated large areas. The first recorded outbreak of the (eastern) spruce budworm in the United States occurred in Maine in about 1807, although it seems to have escaped notice of the entomologists until 1865. Another outbreak followed in 1878. Since 1909 there have been waves of budworm outbreaks throughout the eastern United States and Canada. Longer-term tree-ring studies suggest that spruce budworm outbreaks have been recurring approximately every three decades since the 16th century. The first recorded outbreak of the western variety, which was in 2008 from occidentalis rechristened freemani, occurred in 1909 on the southeastern part of Vancouver Island in British Columbia, Canada. Since that year, infestations have frequently been reported in western Canada. The budworm was first recorded in 1914 in the United States, in Oregon. However, it was not initially recognized as a serious threat to coniferous forests in the western U.S. In Atlantic Canada, the spruce budworm problem was noted as early as 1910. In locations such as New Brunswick, DDT pesticide was applied to over 3.6 million hectacres from 1952 to 1958 and 1960 to 1967. This use of chemical control effectively decreased the spruce mortality rate within this area and prevented significant economic impact. In fact, the government of New Brunswick formed Forest Protection Limited (FPL) as an agent with which 'to fight the spruce budworm then threatening to destroy much of New Brunswick's fir-spruce forest'. The Nova Scotia island of Cape Breton was also affected by the 1952 outbreak, but they chose not to spray pesticides. The infestation collapsed from natural causes within five years. Estimates of the spruce mortality were on the order of 100,000 cords, of which 60% was recovered because the valuable wood is left untouched by the insect and can be harvested profitably. The budworm eats only the needles, which have no economic value apart from being part of the mechanism for survival and growth. By the late 1960s, Fenitrothion had been developed to replace DDT, whose adverse health and environmental effects were already noted. By winter 1975, medical staff at the Killam Hospital for Children in Halifax remarked that every child with a diagnosis of Reye's syndrome was a New Brunswicker, and later proved a link between the syndrome and the emulsifier used to apply the Fenitrothion. As a consequence of the furore surrounding the discovery of the Reye's syndrome link with pesticides, in 1976 the Nova Scotia Minister of Health, Allan Sullivan, cancelled a pesticide spraying programme that had only recently been approved by Cabinet. Erik Sunblad, then president of Stora Koppenberg, who controlled the petitioner Nova Scotia Forest Industries, had threatened to shut down the works if his spraying programme met with official disapproval.