In tests conducted on the Kenai National Moose Range, Alaska, seudenol and α-pinene attracted more spruce beetles (Dendroctonus rufipennis (Kirby)) than did frontalin and α-pinene, the best previously reported synthetic attractant. Addition of methylcyclohexenone (MCH) to sticky traps baited with spruce logs (Picea glauca (Moench) Voss.) infested with 20 female spruce beetles or to traps treated with seudenol and α-pinene reduced the number of spruce beetles caught by 87% and 99%, respectively. MCH appears to have similar repressive effect on the attraction of spruce beetle populations that differ in their geographic locations and hosts. A total of 179 other scolytids, representing 8 genera and 10 species, were caught by traps; greatest numbers were attracted to treatments containing trans-verbenol and uninfested spruce log sections. Scierus pubescens (Swaine) was recorded from Alaska for the first time. No members of Thanasimus species were caught although they have been consistently present in abundance in similar tests elsewhere.

In tests conducted in the McKinley River drainage, Alaska, seudenol combined with α-pinene attracted the most eastern larch beetles, Dendroctonus simplex LeConte. The next most attractive treatments included tamarack log sections infested with either unmated female D. simplex or unmated female Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, Neither frontalin nor trans- verbenol with α-pinene was attractive. Addition of niethylcyclohexenone (MCH) to the seudenol + α-pinene treatment repressed its attraction by 83%. Sex ratios of simplex responding to logs infested with female simplex or pseudotsugae were equal or favored females, but favored males in the case of seudenol + α-pinene. Addition of MCH shifted the sex ratio in favor of females. Two other scolytid species, Orthotomicus caelatus (Eichhoff) and Ips perturbatus (Eichhoff), were trapped, but were too few to relate to treatments. Two species of clerids were caught on traps: Thanasimus undatulus Say and Thanasimus dubius (L.); the latter is a new Alaskan record.

No abstract

Can. Ent. 108: 893-896 (1976) Cacodylic acid was injected into hatchet-made frill girdles 60 cm above the ground on Dutch elm-diseased American elms (Ulmus americana L.) at the rate of 0.8 ml/cm circumference measured 1.3 m above the ground. Cacodylic acid was translocated up the trees into the phloem. Arsenic residue analyses at several different heights in each tree indicated an inverse relationship between height and amount of cacodylic acid residue in the phloem. Largest amounts were translocated in trees with 75% wilted crowns.Cacodylic acid injection into elms had no significant inhibitory effect on Scolytus multistriatus (Marsham) brood development. Cacodylic acid residues as high as 1700 ppm caused little or no beetle mortality. Highest numbers of beetles/dm2 bark surface area emerged from acid-treated elms with 75% crown wilt and from untreated elms with 100% crown wilt.'A silvicide consisting of 50% cacodylic acid and 50% inert ingredients; manufactured by The Ansul Company, Marinette, Wisc.

Douglas-fir beetle populations were monitored before and after thinning and felling of trees to create down wood in an 88-year-old Douglas-fir plantation in the Oregon Coast Range. Treatments included an unthinned control, thinning to a target of 75 trees/ha, and thinning to a target of 150 trees/ha. Actual mean tree densities on the plots after thinning were 406, 102, and 154, for the control, 75 trees/ha, and 150 trees/ha treatments, respectively. Fifty trees/ha were felled and left on all thinned plots to create down wood for ecological values. Catches in pheromone-baited traps indicated that the local beetle population increased for 1 year in response to felling and leaving large diameter trees in partial shade. Douglas-fir beetle entrance holes and brood were significantly more abundant on the sides of felled trees and wood borers were significantly more abundant on the upper surface suggesting that treatments that provide maximum exposure of felled trees will create the least favorable habitat for Douglas-fir beetles. However, there were no differences in Douglas-fir beetle entrance holes or brood densities in felled trees between the two thinning intensities. Douglas-fir beetle-caused tree mortality was significantly higher on thinned plots with residual felled trees compared with unthinned controls, although infestation levels were low on all plots (<2 trees/ha). The small increase in beetle-caused tree mortality associated with leaving felled trees would be unlikely to interfere with resource management objectives. These results are applicable to mature, managed forests west of the Cascades with relatively low Douglas-fir beetle populations. In different regions and stand types, or under different environmental conditions, beetle populations could increase to higher densities, remain at high densities longer, and cause higher levels of tree mortality. West. J. Appl. For. 21(3):117–122.