Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): David B. Orr; Charles P-C Suh; Kenneth W. McCravy; C. Wayne Berisford; Gary L. Debarr
    Date: 2000
    Source: <i>The Canadian Entomologist</i> <b>132:</b> 373-386 (2000)
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (341 KB)


    Inundative releases of Trichogramma exiguum Pinto and Platner were evaluated for suppression of the Nantucket pine tip moth, Rhyacionia frustrana (Cornstock), in first-year loblolly pine, Pinus taeda L., plantations. Three releases, spaced 7 d apart were made in three 0.4-ha plots during second-generation R. frustrana egg deposition. Each release included three cohorts of 7: exiguum developmentally separated by 25 degree-days. Mean ± SD field release rate for each cohort was 328 238 ± 88 379 females/ha. Mean T. exiguum emergence under laboratory conditions for released cohorts was 96 ± 2%, with 74 ± 3% females, of which 1 ± 1% of females displayed brachyptery; female longevity was 18 ± 3 d. Field emergence averaged 96 ± 4%. Parasitism of R. frustrana eggs was significantly increased, ranging from 40 ± 19 to 73 ± 22% in 1: exiguum-treated plots and 17 ± 17 to 67 ± 21% in control plots. Data from all treated plots combined showed R. frustrana egg survival (hatching) was significantly reduced by 46%, and larval populations were significantly reduced by 60%. There was no significant difference in the percentage of terminals damaged between T. exiguum-treated (31 ± 16%) and control plots (45 ± 10%); however, length of terminal damage was significantly lower in treated plots. The percentage of damage to top whorl shoots was significantly lower in T. exiguum-treated plots compared with control plots, but there was no significant difference in length of tunneling damage. Damage to remaining shoots was not significantly different between T. exiguum-treated and control plots. Microhabitat significantly influenced both mean maximum and minimum temperature and the number of consecutive hours per day that were at or above 35°C (critical temperature for T. exiguum survival). Soil surface with no cover had the greatest number of hours at or above 35°C. followed by soil surface with herbaceous cover, and canopies of small trees (0.4 m tall). Canopy habitats in larger trees (0.9-1.8 m tall) had the most moderate temperature conditions. Parasitoid emergence was significantly reduced in response to increasing number of consecutive hours at or above 35°C. Predation of parasitoids prior to emergence was significantly affected by microhabitat and by the length of time capsules were in the field before T. exiguum emergence (i.e. cohort number).

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Orr, David B.; Suh, Charles P-C; McCravy, Kenneth W.; Berisford, C. Wayne; Debarr, Gary L. 2000. Evaluation of Inundative Releases of Trichogramma exigum (Hymenoptera: Trichogrammatidae) for Suppression of Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) in Pine (Pinaceae) Plantations. The Canadian Entomologist 132: 373-386 (2000)

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page