. Eastern forest insects . rcawa Z5 < u. :T $*®s !&£*^ -*-% *i F-488104 Figure 79.—Damage by the pine root collar weevil, Hylobius radicis, at the base of a pine tree. A-v* i*-if«l': the root collar and layers of pitch-infiltrated soil near damaged areas are evidences of infestation. A number of silvicultural prac- tices have been suggested for reducing populations (780). Finne- gan and Stewart discussed methods of direct control (251). Hylobius rhizophagus M. B. & W. is a newly-described species recently discovered attacking jack pine in the Lake States (532). The adult is black an
. Eastern forest insects . rcawa Z5 < u. :T $*®s !&£*^ -*-% *i F-488104 Figure 79.—Damage by the pine root collar weevil, Hylobius radicis, at the base of a pine tree. A-v* i*-if«l': the root collar and layers of pitch-infiltrated soil near damaged areas are evidences of infestation. A number of silvicultural prac- tices have been suggested for reducing populations (780). Finne- gan and Stewart discussed methods of direct control (251). Hylobius rhizophagus M. B. & W. is a newly-described species recently discovered attacking jack pine in the Lake States (532). The adult is black and about mm. long. Dense patches of coarse scales occur on the dorsum and the elytra bear longitudinal rows of pits containing fine setae. The larvae feed in roots less than one-half inch in diameter, tunneling from the smaller end toward the base. Pupation occurs in cells in the roots. Pole-sized pines in closed plantations on formerly cultivated land are most frequently infested; reproduction in well-established infestations and red pines growing in mixture with jack pine are also attacked occasionally. Hylobius warreni Wood attacks most species of conifers grow- ing on moist to wet sites in southern Canada and south to North Carolina in eastern United States. The adult is a large, robust, reddish-brown to black weevil, from 12 to 15 mm. long. The wing covers are thick, tough, and veinless and each bears 10 rows of longitudinal punctures. The hindwings are vestigial. Eggs are deposited around the root collars of healthy trees, and the larvae feed in the inner bark and cambium of roots and root collars for 1 to 2 years. Infested trees bleed heavily at the ground line and severely injured ones may be completely girdled and killed. Up to 40 percent of the trees in a 40-year-old Scotch pine stand in Quebec are reported to have been killed by the species. H. pinicola (Couper) occurs throughout the same range as H. warreni and apparently breeds in the same species of trees
Size: 2212px × 2260px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
