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Observation reveals a southward distribution extension of the balsam woolly aphid impacting grand fir, suggesting potential risks to white fir in California.
The balsam woolly aphid is now well established on grand fir throughout the Coast Range of Oregon and Washington. A southward extension of the insect's distribution of over a hundred miles is reported. Grand fir mortality is slow and difficult to detect, but widespread. As yet, feasible chemical or biological control measures do not exist and if the spread continues, white fir in California may be threatened.
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H. J. Heikkenen (1966) studied this question.
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