3.5 SUPPRESSION OF SPRUCE BUDWORM POPULATIONS BY TRICHOGRAMMA MINUTUM RILEY, 1982–1986

1990 ◽  
Vol 122 (S153) ◽  
pp. 56-81 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace ◽  
G. Howse ◽  
J. Meating

AbstractThe ability of the egg parasitoid, Trichogramma minutum Riley, to suppress outbreak populations of the spruce budworm, Choristoneura fumiferana (Clemens), was studied annually near Hearst, Ont., from 1982 through 1986. Timing of broadcast parasitoid-releases was linked to spruce budworm moth emergence and oviposition. These phenological relationships were predicted from a regression based on larval development at least 2 weeks before expected emergence; this allowed sufficient time to regulate (program) parasitoid emergence during mass-rearing. Emergence of caged spruce budworm adults was used to monitor moth eclosion in the field. Pheromone traps provided daily information on the activity of male moths and helped to synchronize the parasitoid releases with spruce budworm oviposition. Information on parasitoid activity was obtained from sentinel (laboratory-reared) and naturally occurring spruce budworm egg masses. A curvilinear relationship between the rate of parasitoid release and parasitism of sentinel egg masses was developed. Two parasitoid releases, 1 week apart, early in the oviposition period of spruce budworm, significantly increased parasitism of host eggs by 14–83% and reduced larval populations correspondingly from 42 to 82%. Single releases were less effective and increased parasitism by 0.3–52% (single ground release, 1986). Two parasitoid releases, combined with a spring application of Bacillus thuringiensis Berliner to larval populations, was the most effective strategy and resulted in 83% egg parasitism and 93% larval reduction. Release rates greater than 12–16 × 106 ♀ ♀ T. minutum per hectare were not warranted based on impact and costs. The effects of release timing, weather, host density, and parasitoid quality on the future successful use of T. minutum are discussed.

1987 ◽  
Vol 119 (3) ◽  
pp. 251-263 ◽  
Author(s):  
S.M. Smith ◽  
M. Hubbes ◽  
J.R. Carrow

AbstractDuring 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.


1990 ◽  
Vol 122 (S153) ◽  
pp. 45-55 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace ◽  
J.E. Laing ◽  
G.M. Eden ◽  
S.A. Nicholson

AbstractThe egg parasitoid, Trichogramma minutum Riley, was distributed by helicopter over forest stands near Hearst, Ont., to control the spruce budworm, Choristoneura fumiferana (Clemens). The quality of the parasitoids in terms of emergence, proportion of females, longevity, and fecundity was not affected by aerial release. Based on monitoring with deposit cards, at 10 m above ground, the helicopter had an effective swath width of ca. 10 m. Aerial release provided an uneven distribution of deposit on 1.0-ha plots, with significantly less parasitized material reaching the outer edges of each plot than in the centre; parasitism of sentinel egg masses within the plots corresponded to the distribution of deposit. Over 50% of the released material was deposited on the ground. Drift outside the plots was generally less than 25 m, never exceeding 100 m. The extent of drift was dependent on the application technique, and to a lesser extent, wind direction. Deposit cards provided an extensive rather than an intensive sampling method for monitoring the aerial distribution of T. minutum.


Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 840
Author(s):  
Barbara Bittau ◽  
Maria Luisa Dindo ◽  
Giovanni Burgio ◽  
Giuseppino Sabbatini-Peverieri ◽  
Kim Alan Hoelmer ◽  
...  

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), a pest of Asian origin, has been causing severe damage to Italian agriculture. The application of classical biological control by the release of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), an exotic egg parasitoid, appears to be one promising solution. In Italy, releases of T. japonicus in the field were authorized in 2020. In this study, some parameters that could influence the rearing of T. japonicus in insectaries were investigated. A significantly higher production of progeny was observed on host eggs stored at 6 °C (86.5%) compared to −24 °C (48.8%) for up to two months prior to exposure to parasitism. There were no significant differences in progeny production from single females in a vial provided with only one egg mass (83.2%) or 10 females inside a cage with 6 egg masses (83.9%). The exposure of parasitoids to refrigerated (6 °C) egg masses of H. halys for 72 h led to a significantly higher production of progeny (62.1%) compared to shorter exposures for 48 (44.0%) or 24 h (37.1%). A decline in production of progeny by the same female was detected between the first (62.1%) and the second parasitization (41.3%). Adult parasitoids stored at 16 °C for up to 90 days had an 87.1% survival rate, but a significant decrease in progeny production was detected. These parameters could be adjusted when rearing T. japonicus for specific aims such as the production of individuals for field release or colony maintenance.


2007 ◽  
Vol 139 (6) ◽  
pp. 834-840 ◽  
Author(s):  
Kees van Frankenhuyzen ◽  
Peter Ebling ◽  
John Dedes ◽  
Doug Pitt

AbstractThe spruce budworm, Choristoneura fumiferana (Clem.), has an obligatory winter dormancy period that lasts up to 10 months in the field. In the Great Lakes Forestry Centre rearing facility, neonate larvae spin hibernacula in cheesecloth, which is then stored at 2 °C for between 20 and 30 weeks. Although dormancy survival and synchrony of postemergence development are highest when larvae are stored in the cold for 16–35 weeks, it is not known how cold-storage duration affects spruce budworm performance once diapause has been completed. We exposed approximately 9250 second-instar larvae (belonging to three rearing cohorts) to 2 °C for 16, 19, 22, 25, 28, 31, 34, or 37 weeks and monitored various postdiapause performance variables. Increasing cold storage from 16 to 25 weeks or more resulted in small (approximately 10%) increases in dormancy survival and larval development rates (from second instar to pupation), a larger (up to 23%) increase in pupal mass and realized fecundity (number of eggs laid per female), and an increase of at least 25% in late-instar survival (from fifth instar to pupation). The only variable that was negatively affected was the pupal survival, but the decrease was relatively small. Therefore, storing diapausing larvae for at least 25 weeks optimizes postdiapause performance variables that are important for mass-rearing efficiency.


1987 ◽  
Vol 65 (8) ◽  
pp. 2047-2050 ◽  
Author(s):  
V. G. Nealis ◽  
S. M. Smith

The relationship between a braconid parasitoid, Apanteles fumiferanae, and a microsporidian pathogen, Nosema fumiferanae, two larval parasites frequently coincident in the spruce budworm, Choristoneura fumiferana, was examined in the laboratory. When Apanteles was reared in spruce budworm infected with high levels of Nosema (i.e., more than 20 × 106 spores/mg dry weight), there was a slight reduction in the within-host rate of development of larval female Apanteles, but survival, within-cocoon rate of development, cocoon weight, and adult longevity were not affected. There was no evidence that any stage of Apanteles was infected with spores of Nosema. A few adult female parasitoids were found to carry spores of Nosema on their integuments but it is unlikely that Apanteles is an important vector of the microsporidian. We conclude that these natural enemies of budworm do not interact significantly in their common host. The implications for population dynamics of the spruce budworm and mass rearing of Apanteles are discussed.


Author(s):  
Adam Formella ◽  
Seth J Dorman ◽  
Sally V Taylor ◽  
Thomas P Kuhar

Abstract The brown marmorated stink bug, Halyomorpha halys (Stål), is a polyphagous pest that feeds on a wide variety of agricultural commodities including tree fruits, berries, vegetables, field crops, and ornamental trees and shrubs. Accurate knowledge of where H. halys lays eggs is critical to optimize the potential release of Trissolcus japonicus (Ashmead), a scelionid egg parasitoid native to the same host region as H. halys. Ideally, parasitoids should be released in and around areas with high host density. In southwestern Virginia in 2017 and 2018, we searched trees for egg masses in an urban environment and nonmanaged wooded border environment. We also evaluated the effects of a commercial aggregation lure on the number of eggs being deposited. This aggregation lure, when combined with methyl (E,E,Z)-2,4,6-decatrienoate (MDT), has been shown to attract both adult and nymph H. halys and its effects on egg laying were not known. Results of this study showed no difference between the number of eggs laid on trees with and without lures. Catalpa trees, Catalpa bignonioides Walter, had the most egg masses throughout the course of the study; however, the redbud, Cercis canadensis L., had similar numbers in the late July and August. There was an overall trend with more eggs masses found on trees with fruiting structures present. This information can provide insight on where and when to make augmentative releases of egg parasitoids for H. halys.


Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 318 ◽  
Author(s):  
Cornelius ◽  
Vinyard ◽  
Gates

A two-year study evaluated the effect of a flowering border of buckwheat Fagopyrum esculentum Moench on rates of egg parasitism, egg predation and adult parasitism on two squash bug species, Anasa tristis (DeGeer) and Anasa armigera Say, by comparing rates in squash fields with and without a flowering border. Furthermore, we evaluated whether there was an edge effect by comparing parasitism and predation rates in plots located in the corner of a squash field with plots located in the center of a squash field for fields with and without a flowering border. The egg parasitism rates were not affected by either treatment (flowering border or control) or plot location (edge or center). Anasa armigera egg masses only accounted for 4.3% of the total egg masses collected. The egg parasitism rates increased gradually throughout the season, peaking in the last week of August in 2017 at 45% for A. tristis egg masses. The most common egg parasitoid recovered was Gryon pennsylvanicum (Ashmead) followed by Ooencyrtus anasae (Ashmead). Adult parasitism was not affected by treatment, but A. tristis adult parasitism rates were higher in plots located on the edge of squash fields compared with plots located in the center of squash fields in 2016. Since adult parasitoid, Trichopoda pennipes (Fabricius) flies were observed visiting buckwheat flowers, future studies could explore the possibility that the flowering buckwheat may have a more impact on adult parasitism if there was a greater distance between fields with and without a flowering border.


1983 ◽  
Vol 115 (4) ◽  
pp. 439-440
Author(s):  
Daniel T. Jennings ◽  
Hewlette S. Crawford

During preoutbreak periods before spruce budworm, Choristoneura fumiferana (Clemens), populations reach epidemic levels, birds can play an important role in regulating budworm abundance (Gage and Miller 1978). All life stages of the spruce budworm are subject to predation by birds, but documentation of predation on budworm eggs is sparse (Hope 1945).


1982 ◽  
Vol 114 (8) ◽  
pp. 657-666 ◽  
Author(s):  
Mark W. Houseweart ◽  
Susan G. Southard ◽  
Daniel T. Jennings

AbstractSpruce budworm egg deposition spanned 27 days during both 1979 and 1980. The egg deposition curve is essentially a normal bell-shaped distribution with a slight skew to the right. Spruce budworm eggs are most acceptable to T. minutum Riley for successful parasitism during the earlier stages of host–egg development. Parasitism rates at two different temperatures (21 °C and 27 °C) were significantly greater for 1- to 3-day-old eggs than for 6- to 8-day-old spruce budworm eggs. Major reduction in host–egg acceptability occurred after the fifth day at 21 °C and after the 4th day at 27 °C.


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