Only Abies amabilis (Dougl.) Forbes heavily defoliated by a sawfly, Neodiprion sp., supported broods of Pseudohylesinus spp.. Although many trees with less defoliation showed evidence of attack, usually it was caused by adult beetles making overwintering niches. P. granulatus (Leconte) was found on the lower bole, whereas P. grandis Swaine and P. nobilis Swaine were found on the upper bole. Defoliated Tsuga heterophylla (Raf.) Sarg. were not attacked by bark beetles

Fiddick, R. L.

McMullen, L. H.

Wood, R. O.

Only &lt;i&gt;Abies amabilis&lt;/i&gt; (Dougl.) Forbes heavily defoliated by a sawfly, &lt;i&gt;Neodiprion&lt;/i&gt; sp., supported broods of &lt;i&gt;Pseudohylesinus &lt;/i&gt;spp.. Although many trees with less defoliation showed evidence of attack, usually it was caused by adult beetles making overwintering niches. &lt;i&gt;P. granulatus&lt;/i&gt; (Leconte) was found on the lower bole, whereas &lt;i&gt;P. grandis&lt;/i&gt; Swaine and &lt;i&gt;P. nobilis&lt;/i&gt; Swaine were found on the upper bole. Defoliated &lt;i&gt;Tsuga heterophylla&lt;/i&gt; (Raf.) Sarg. were not attacked by bark beetles

Journal of the Entomological Society of British Columbia

J. ENTOMOL. Soc. BR IT. CO LUMB IA 78 11 981). DEC. 31, 1981 43 BARK BEETLES, PSEUDOHYLESlNUS SPP. (COLEOPTERA: SCOLYTIDAE), ASSOCIATED WITH AMABILIS FIR DEFOLIATED BY NEODIPRION SP. (HYMENOPTERA: DIPRIONIDAE) By L. H. McMuLLEN , R. L. FIDDICK AND R. O. WOOD Environment Canada Canadian Forestry Service Pacific Forest Research Centre 506 West Burnside Road Victoria, B.C. V8Z IM5 RESUM E Seul Abies amabilis ID oug!.) Forbes, Severement defolie par un Diprion (Neodiprion sp .) abritait des couvees de Pseudohy Lesinus spp . Bien que de nombr~ux suj ets d'A bies ayant subi une defoli ation moins grave ali ent montre des s ignes d 'a t taque par l'insec te, il s 'agi ssai t habi t uellement de dipri ons adul tes construisanL des hibernacles. P. granlllatll s se trouvait da ns la par tie inferieure du fu t alors que P . grandis Swa ine et P. nobilis Swaine se trouvaient dans la part ie superi eure. Le Tsuga heterophy lla I Raf.) Sarg. n'a pas subi l'attaque des scolytes de l'ecorce. ABSTRACT Only Abies amabilis (Doug!.) Forbes heavily defoliated by a sawfly, Neodiprion sp ., supported broods of Pseudohy lesinus spp .. Although many trees with less defoliation showed evidence of attack, usually it was caused by adult beetles making overwintering niches. P . granulatus (Leconte) was found on the lower bole, whereas P. grandis Swaine and P. nobi/is Swaine were found on the upper bole. Defoliated Tsuga heterophylla (Raf.) Sarg. were not attacked by bark beetles. INTRODUCTION Stands of amabilis fir (A bies amabilis (Doug!.) Forbes) and western hemlock (Ts uga heterophy lla (Raf.) Sarg. ) near Kelsey Bay, B.C., were severely defoliated by a sawfly , Neodiprion sp ., in 1978 and 1979 (Van Sickle and Fiddick 1979). Although the sawfly infes-tation subsided in 1980, the bark beetle Ps eudohy lesinus granula tus (Leconte) ' a ttack-ed the lower bole of many of the amabilis fir trees. This study was carried out to assess the hazard of the bark beetle to nearby undefoliat-ed trees and those trees recovering from de-foliation and it also provides the first record of Pseudohy lesinus associated with sawfly defoliation in B.C . METHODS On 23 to 25 September, 1980, the defoliated stands were examined along three cruise lines : two near Keta Lake (elev 400 m) and one near Big Tree Creek (elev 700 mi . Tree species, diameter breast height, defoliation estimates and evidence of bark beetle attack were record-ed for each tree on 25 and 7 prism (B.A.F . 5, m'/ ha) plots in the two locations, respectively. 'Identi fi ed by R. W. Duncan , Paci fi c Forest Research Centre. Victoria. 'Identified by D. E. Bright , Agricul tu re Canada, Bio-systffila tics Research I ns titute. Ottawa. The defoliation data were derived from visual estimates of filiage missing from the tree. Ten amabalis fir trees , averaging 45 cm dbh and 33 m ht and ranging from 71 to 100% de-foliation, with boring dust on the lower bole were felled within the Keta Lake infestation . Four circular samples of bark (each 81 cm' ) were removed within 0.3 m of the ground and two were taken at each 3 m interval along the bole from 1.5 m height to a 20-cm-diameter top. Numbers of entrance holes, living parents, pro-geny and emergence holes were counted and gallery length was measured on each sample. RESULTS AND DISCUSSION On many trees over 90% defoliated , the only foliage remaining was that of the current 1980 growth . Although both Abies and Tsuga were defoliated, only the Abies were attacked by bark beetles. The attack appeared to be posi-tively correlated with intensity of defoliation and tree diameter (Table 1). I n addi t ion to P. gran ll Lallls attacks on the lower bole, two other species of Pseudohyles-inus, P. grandis Swaine and P. nobilis Swaine', were found on the upper bole. Adults were not found in the brood galleries of any of the three species ; the only adults were in holes, undoubt-edly overwintering sites , excavated just to the cambium (Thomas and Wright 1961 ; Dyer and 44 J. ENTOMOL. Soc. BHIT. COLUMBIA 78 (1981), DEC . 31 , 1981 Table. 1. Numbers of Abies amabilis along cruise lines and percent attacked by bark beetles (in parenthesis) arranged by defoliation a nd diameter classes, Kelsey Bay, September 1980. Percent defoliation c lass Diameter class (cm) 25-50 51-80 15-30 4 ( 0) 8 ( 0) 31-50 7 ( 0) 27 (40) 51-70 5 ( 0) 37 (62) 71-100 3 (33) 8 (38) Total 19 ( 5) 80 (46) Nijholt 1965; Bright 1976). Although P. grandis and P. nobilis were probably respon-sible for the attack producing brood in the upper bole, identification was made only from beetles in these overwintering sites. Based on their large size, the gallery systems of P. 81-90 91-100 Total 2 (50) 6 (50) 20 (20) 15 (33) 41 ( 63) 90 ( 47) 2 (50) 16 (62) 60 (57) 2 (100) 5 (100) 18 (61) 21 (43) 68 (65) 188 (48) granulatu s were easily distinguished from those of the other two species . P. granulatus galleries occurred from the base of the trees only up to 10.5 m on the bole. The remaining two species occurred from 7.5 m upward (Table 2) but, on any individual tree. were not mixed with P. Table 2. Number of Pseudohylesinus attacks and progeny and egg gallery length (cm), per 0.1 sq m of bark in 10 Abies amabilis defoliated by Neodiprion , Keta Lake, September 1980. Pe r ce n t 1' . g r anulatus P - s pp . defollat i. on No . of lIeight!i No . of tJu[:1her of Ca l1ery Numbe r of Ca lIe r y classes t rees samples Attac k s27 Progeny length i\ttacksl7 Progf'ny leng th 71 - 80 40 2 . 8 0 . 0 5 . I 0 . 0 0 . 0 0 . 0 ]2 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 22 0 . 0 1) . 0 0 . 0 7. 3 0 . 0 12 . , All 94 1. 2 n.n 2 . 2 1. 7 n.lI 2 . 9 8 1-90 211 1.8 3 . I 0 . 9 0 . 0 0 . 0 0 . 0 16 0 . 0 1) . 1I 0 . 0 4 . 6 0 . 0 1. 2 10 f) .I ) 0 . 0 0 . 0 9 . 9 2 . 5 18 . 9 All 1.6 0 . 8 I . J n.4 ' .8 Il . 'i 4 .5 91 - 100 40 J . I ~n . 4 15.1! 0 . 6 l . 5 I. ] 12 1) . 8 6 . h ,. ] 5 . 8 29 . 7 20 .9 14 (l . 0 D. O 0 . 0 8 . 8 L13 . 2 89 . J All 8 6 1.7 11.9 8 . 2 J . 9 18 . 8 22 . 9 1/ 1 " b:=!se to 7 . 5 Q , 2 " 9 . 0 t o 19. 0 [1 , J " 22 . 'j+ [;1 . l) lne 1 ud es atta ck made by beet l es in over ..... inte ri ng nie-he. J. ENTOMOL. Soc. BRIT. COLUMBIA 78 11981), DEC . 31,1981 45 granulatus. The association between P. granula-and P . grandis is well known (Thomas and Wright 1961; Bright 1976), but the role that P. nobilis may play in such an association is unknown . The progeny of P. granulatus were all larvae and that of the other two species were larvae and pupae, and some exit holes were present. The number of exit holes was combined with the number of living progeny to provide the total of progeny for the data collected from the bark samples (Table 2) . Neither progeny nor larval mines were found in trees in the lowest defoliation class examined (71 to 80%). although a few aborted egg gal-leries were present (Table 2). Trees in the inter-mediate defoliation class (81 to 900/0) contained a few successful galleries with a few progeny, but many attacks were unsuccessful. Success-ful beetle broods were present primarily in trees in the most severe defoliation class. These trees essentially had only 1980 foliage and often this was sparse. Based on the presence of boring dust ob-served during the cruise of standing trees a relatively high proportion (48%, Table 1) of the Abies were attacked by bark beetles. The bark samples and the literature (Thomas and Wright 1961 ; Dyer and Nijholt 1965; Bright 1976) suggest that most of these attacks would have been beetles making overwinering niches rather than beetles attempting to construct brood galleries. The spec ies responsible would have been primarily P . granulatus, although P . gran-dis could have contributed (Dyer and Nijholt 1965). Only the severely defoliated trees were sup-porting successful bark beetle broods . These trees were already dead or dying, and the beetles appeared to be an unlikely source of serious hazard to nearby undefoliated trees or to those recovering from the effects of defolia-tion . This note is the first record of Pseudohyles-inus spp. associated with sawfly defoliation in B.C . However, Pseudohylesinus spp. were implicated following the western hemlock looper (Lambdina fi scellaria lugubrosa (Hults)) .outbreak of 1944-46 (Kinghorn 1954) and were often associated with the balsam woolly aphid (A de lges piceae (Ratz.)) (Shea et al. 1962; Harris et ai. 1966). REFERENCES Bright, D. E. 1976. The insects and arachnids of Canada . Part II. The bark beetles of Canada and Alaska, Coleoptera : Sculytidae. Can. Dept. Agric. Pub!. 1576,241 pp . Dyer, E . D. A., and W. W. Nijholt. 1965. Observations of overwintering Pseudohy lesinus and Trypodendron . Can. Dept. For . Bi-mon. Prog. Rpt. 21(4) : 3. Harris, J . W. E. , S. J . Allen , D. G. Collis, and E . G. Harvey. 1966. Status of the balsam woolly aphid, Adelges piceae (Ratz.), in British Columbia, 1965. Dept. For. Res. Lab., Victoria, Inf. Rept. BC-X-5. Kinghorn , J . M. 1954. The influence of stand composition on the mortality of various conifers caused by defoliation by the western hemlock looper on Vancouver Island, British Columbia. For . Chron. 30: 380-400. Shea, K. R., N. E. Johnson , and S. McKee . 1962. Deterioration of Pacific silver fir killed by the balsam woolly aphid. J. For. 60: 104-108. Thomas, G. M., and K. H. Wright. 1961. Silver fir beetles . U.S. Dept. Agric. For . Pest Leafl . 60, 7pp. Van Sickle, A., and R. L. Fiddick. 1979. Sawfly infestation near Kelsey Bay, Vancouver Island. Envir. Can. For . Serv . Pacific For. Res . Centre Pes t Rept., October, 2 pp . 

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Bark beetles, Pseudohylesinus spp. (Coleoptera: Scolytidae), associated with amabilis fir defoliated by Neodiprion sp. (Hymenoptera: Diprionidae)

https://journal.entsocbc.ca/index.php/journal/article/download/1989/2055

Bark beetles, Pseudohylesinus spp. (Coleoptera: Scolytidae), associated with amabilis fir defoliated by Neodiprion sp. (Hymenoptera: Diprionidae)

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Journal of the Entomological Society of British Columbia