Green ash windbreaks in North Dakota were surveyed in 1972 and 1976 to determine the incidence of attacks by the carpenterworm, ash borer, and other stem-infesting wood borers. Windbreaks were stratified by age and geographic region. In 1976, about 3.1 percent of the green ash trees in North Dakota had new carpenterworm attacks, an increase of 34.8 percent from 1972. The number of trees showing new attacks by the ash borer declined in three out of four land resource areas (LRA). Trees damaged by other borers declined in all LRA's but one. Although some LRA's showed minor increases, the number of windbreaks infested by the carpenterworm and ash borer declined by 41.6 percent and 19.6 percent respectively. Younger windbreaks were apparently more susceptible to attack by ash borers while older ones were more frequently infested by the carpenterworm and other borers.
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