Seasonal changes in intra-tree distribution of immature balsam fir sawfly (Hymenoptera: Diprionidae)

2002 ◽  
Vol 134 (4) ◽  
pp. 529-538 ◽  
Author(s):  
Lynne J. Anstey ◽  
Dan T. Quiring ◽  
Don P. Ostaff

AbstractA field study was carried out to determine the intracrown distribution of the balsam fir sawfly, Neodiprion abietis Harris (Hymenoptera: Diprionidae), throughout the season on balsam fir, Abies balsamea L. (Pinaceae), during the first 2 years of an outbreak in western Newfoundland. Eggs were usually laid one per needle on current-year shoots, and the following year, newly emerged larvae usually initiated feeding on the same shoots. Balsam fir sawfly larvae were gregarious on needle and shoot levels in the early instars but gradually became solitary as larvae developed. The process of becoming solitary was not due to the increased physical area required for the growing larvae as some older individuals, in mainly solitary stages, were seen feeding together. Unlike the continuous change from gregarious to solitary at the needle and shoot levels, the seasonal variation in larval density among whorls varied in an inconsistent manner. The majority of early-instar larvae were found in the middle crown, but on at least one date in both years the majority of late instars were in the lower crown. Seventy-five percent of crawling larvae trapped within the crown were third and fourth instars, suggesting that changes in the intra-tree distribution are due to larval movement.

2001 ◽  
Vol 133 (5) ◽  
pp. 675-686 ◽  
Author(s):  
Harald Piene ◽  
Don P. Ostaff ◽  
Eldon S. Eveleigh

AbstractTwo stands of intensively managed balsam fir [Abies balsamea (L.) Mill. (Pinaceae)] in western Newfoundland, located within an area infested by the balsam fir sawfly, Neodiprion abietis (Harr.) (Hymenoptera: Diprionidae) complex, were selected to study growth loss and recovery following severe defoliation by the balsam fir sawfly in the early 1990s. Four years after the start of the outbreak, volume increments were reduced by 78–81%. The decreased volume increment and recovery coincided well with the balsam fir sawfly outbreak and decline. The growth recovery rates following severe balsam fir sawfly defoliation were slow due to the absence of bud destruction, which triggers the release of suppressed buds, and thus increases foliage production. It is imperative that the severe losses in volume growth caused by balsam fir sawfly defoliation are incorporated into wood supply analyses so that future annual allowable cuts may be adjusted. In addition, to ensure maximum recovery rates at the end of an outbreak, future populations must be kept at a minimum to avoid additional foliage loss.


1998 ◽  
Vol 28 (5) ◽  
pp. 703-710 ◽  
Author(s):  
Erhard John Dobesberger

A stochastic simulation model was developed to derive a damage function for the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), and balsam fir, Abies balsamea (L.) Mill., herbivore interaction at the stand level for open-grown trees. Both aggregated and uniform models of attack pattern by late-instar larvae based on k of the negative binomial were evaluated to determine the impact of larval density and attack pattern on the loss in stemwood volume increment of young, thinned balsam fir stands in Newfoundland. Percentage loss in stemwood increment was a nonlinear, negative exponential function of initial larval density. Implementation of control measures to prevent 50% defoliation that is caused by about 14 larvae/branch tip would result in saving 24% of the annual stemwood increment after 1 year of defoliation and about 32% after 2 years of cumulative defoliation. Aggregation of spruce budworm larvae among trees within a forest stand results in less growth loss compared with a uniform pattern of attack. The nonlinear damage function may suggest tolerance and possibly compensatory growth after herbivory by low population levels of the spruce budworm.


1993 ◽  
Vol 125 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Beresford L. Cadogan ◽  
Roger D. Scharbach

AbstractThe insecticide Foray 48B (Bacillus thuringiensis var. kurstaki Berliner) was applied undiluted at 30 BIU per ha to control spruce budworm, Choristoneura fumiferana (Clem.), in a mixed boreal forest stand of balsam fir, Abies balsamea (L.) Mill., and black spruce, Picea mariana (Mill.) B.S.P. When the treatment was timed to coincide with the early flushing of balsam fir shoots, the corrected budworm population reductions were 74 and 52% on balsam fir and black spruce, respectively. This treatment resulted in 19 and 8% defoliation on the two respective species. When the insecticide application was timed later to coincide with the late flushing of black spruce shoots the corrected population reductions were 93% on balsam fir and 72% on black spruce. Defoliation of the two species was 29 and 10% respectively, following this treatment. Larval survival on both species after the spray timed for black spruce (0.8 and 2.2 larvae per 45-cm branch on balsam fir and black spruce, respectively) was significantly less (P = 0.05) than that observed after the spray timed for balsam fir (4.6 and 4.2 larvae per 45-cm branch on the respective host species).The data indicate that the spray timed to correspond with the flushing of black spruce was generally more efficacious than the spray timed to impact on newly flushed balsam fir; nevertheless, the results raise the question as to how B. thuringiensis insecticides impact on early-instar budworm larvae when there is no preferred current year foliage on which the insects can feed.


2016 ◽  
Vol 148 (4) ◽  
pp. 466-475 ◽  
Author(s):  
Richard Berthiaume ◽  
Christian Hébert ◽  
Georges Pelletier ◽  
Conrad Cloutier

AbstractThe balsam twig aphid, Mindarus abietinus Koch (Hemiptera: Aphididae), is one of the most important pests of balsam fir (Abies balsamea (Linnaeus) Miller; Pinaceae) grown as Christmas trees in eastern North America. Aphid feeding on the current-year shoots results in needle distortion and shoots stunting, which reduces the aesthetic value of balsam fir trees and can have substantial economic impact. Syrphidae (Diptera) fly predators attacking this aphid are poorly known. We identified four species attacking the balsam twig aphid. Syrphus torvus Osten Sacken (Diptera: Syrphidae) was the most abundant species followed by Eupeodes lapponicus (Zetterstedt) (Diptera: Syrphidae) and Eupeodes americanus (Wiedemann) (Diptera: Syrphidae). We described the seasonal natural history of the two most abundant syrphids feeding on this aphid and we studied their synchrony with their prey. Syrphid larval density on balsam fir shoots increased rapidly and closely followed density of the balsam twig aphid. We also reported heavy parasitism of syrphid pupae by two Hymenoptera on tree foliage but lower parasitism on pupae in the soil under trees. Several cases of multiple parasitism and hyperparasitism were observed in syrphid pupae under trees. Abundance of predaceous syrphid species was higher in untreated balsam fir plantations compared with treated plantations. More research is needed to understand the role and the impact of these predators on balsam twig aphid population dynamics.


1951 ◽  
Vol 83 (7) ◽  
pp. 181-183 ◽  
Author(s):  
F. E. Webb ◽  
R. S. Forbes

In 1945 injury to shoots of balsam fir, Abies balsamea (L.) Mill., by sawfly larvae was very common in York and Madawaska counties, New Brunswick. Since then, similar injury has been noticed throughout most of New Brunswick, eastern Nova Scotia, the upper peninsula of Michigan and northern Wisconsin.New Brunswick specimens were identified by Dr. O. Peck of the Systematic Unit, Division of Entomology, as presumably Pleroneura borealis Felt, the specimens running to this species in Ross' Key (2); however, as stated by Ross (3), the recognition of species in the genus is not at present based upon fundamental characters. P. borealis was originally described in 1917 by Felt (1) from three specimens collected at Lake Clear, N.Y., in 1907. Except for the taxonomic revision by Ross (2), no other reference to this species was found in the literature.


2013 ◽  
Vol 145 (4) ◽  
pp. 430-434
Author(s):  
Rob C. Johns ◽  
J. Fidgen ◽  
Don P. Ostaff

AbstractLaboratory experiments using field-collected females were carried out to determine the oviposition preference of the balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae) in New Brunswick, Canada. Unmated adult females given no choice among host–plant foliage laid ∼98% of available eggs on balsam fir (Abies balsamea (Linnaeus) Miller; Pinaceae), but only 8% and 10%, respectively, on white spruce (Picea glauca (Moench) Voss; Pinaceae) and black spruce (Picea mariana (Miller) Britton, Sterns, and Poggenburg). Given a choice among shoots from all three hosts in the same chamber, unmated females laid all but one egg in balsam fir. Host plant had no effect on female longevity, although there were nearly four- to eightfold more empty egg slits on balsam fir needles, owing presumably to the greater activity of females on this preferred host foliage.


1986 ◽  
Vol 118 (1) ◽  
pp. 69-77 ◽  
Author(s):  
D.C. Eidt ◽  
V.N. Mallet

AbstractFenitrothion accumulates in foliage tissue of balsam fir, Abies balsamea (L.) Mill., in the forest, but only until about 1.5 μg/g is reached. The balsam fir sawfly, Neodiprion abietis (Harris), which belongs to the family of forest insects known to be most sensitive to fenitrothion, has become rare but persists in New Brunswick in spite of the use of fenitrothion for control of spruce bud worm, Choristoneura fumerifana (Clemens).


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Christopher J. Lucarotti ◽  
Beatrixe H. Whittome-Waygood ◽  
Renée Lapointe ◽  
Benoit Morin ◽  
David B. Levin

TheNeodiprion abietis Gammabaculovirus(Baculoviridae: NeabNPV) is virulent, highly contagious, and infects only midgut epithelial cells of balsam fir sawfly larvae, but infections can carry through to adult sawflies in the midgut. Larval infections are characterized by hypertrophy of midgut epithelial cell nuclei, where virogenic stromata develop to produce nucleocapsids that are singly enveloped before occlusion into occlusion bodies. Infected, occlusion body-laden cells slough from the midgut epithelium as a result of a dissolution of the basal lamina. Infected cells undergo lysis, and viral occlusion bodies exit affected larvae in a watery diarrhea to infect other balsam fir sawfly larvae. A budded virus stage was not observed, but nucleocapsid and occlusion body formation resembled the development of occlusion-derived virions and occlusion bodies in lepidopteran alphabaculoviruses.


2003 ◽  
Vol 135 (5) ◽  
pp. 669-676 ◽  
Author(s):  
John T. Huber ◽  
Gaétan Moreau

AbstractCirrospilus flavoviridis Crawford, syn. nov., is synonymized under C. vittatus Walker. It is newly recorded as a solitary egg parasitoid from eggs of Neodiprion abietis Harris (Hymenoptera: Diprionidae) on balsam fir, Abies balsamea (L.) Mill. (Pinaceace), in New Brunswick and Newfoundland and from eggs of Neodiprion nanulus nanulus Schedl in Wisconsin.


1970 ◽  
Vol 48 (11) ◽  
pp. 2021-2028 ◽  
Author(s):  
C. H. A. Little

Starch, total sugar, fructose, glucose, sucrose, raffinose, crude fat, and moisture contents were determined for current and 1-year-old needles at about 2-week intervals throughout 1968. Seasonal fluctuations in moisture and carbohydrate content of each age of needles are described, compared, and related to seasonal changes in carbohydrate production and use.


Sign in / Sign up

Export Citation Format

Share Document