Distribution and Damage of Two Pineus Species (Homoptera: Adelgidae) on Red Pine in New England

Abstract

Field and greenhouse experiments during 1979 and 1980 revealed that Pineus boerneri Annand and Pineus coloradensis (Gillette) (Homoptera: Adelgidae) infest Pinus resinosa Ait., red pine, and preferentially colonize the 3-year-old growth of the lower crown. However, P. boerneri occurs only beneath bark flakes or at the base of needle sheaths, whereas most P. coloradensis feed only on needles or in the uppermost part of the needle sheaths. Pattern of colonization was not affected by interspecific interaction. P. coloradensis, widely distributed in North America on numerous pines, was collected from 49 of 76 red pine stands throughout New England. However, this adelgid injured trees only at three sites, located south of the natural red pine growing area, where its densities were very high. Generally innocuous to red pine, P. coloradensis likely attains injurious population levels only where trees are stressed. P. boerneri, absent from all 25 northern sites within the natural range of red pine, was collected from 28 of 51 stands in the south and damaged trees at all but six of the infested sites. Injury included discoloration of foliage, distortion, resinosis and death of branches, and death of trees at one site. The limited distribution of P. boerneri in southern New England indicates that this adelgid was introduced into the northeastern United States.