摘要:

Since its discovery in 1957 at St. Maries, Idaho (Denton and Tunnock 1972), the larch casebearer,Coleophora laricella(Hübner), has spread over much of the Pacific Northwest (Andrews 1966, Bousfield and Lood 1973). It now occurs in a significant portion of the range of western larch,Larix occidentalisNutt., in British Columbia.C. laricellais a severe threat to the growth and survival ofL. occidentalis(Tunnock et al. 1969).

ISSN:1754-5692    

DOI:10.1093/ee/3.2.360

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Parasitoid insects are considered to be important mortality agents of the spruce budworm,Choristoneura fumigerana(Clemens) (Lepidoptera: Tortricidae), (Miller 1963). Also the release of exotic parasitoids has long been considered to be a potentially valuable means of controlling this major forest pest and though releases have not yet been successful (Miller and Angus 1971), the search for new exotics continues (Renault and Kamijo 1970). In practice, control of the spruce budworm has relied on the large-scale aerial application of insecticides. This has led to an increasing concern over both the immediate and the long-term effects of such broad-spectrum toxicants on the parasitoids associated with the spruce budworm (Varty et al. 1971, Varty 1972). The possibility that conventional toxicants may eventually be replaced by insecticides based on insect juvenile hormone (JH) will not necessarily eliminate this concern. As yet, there is little evidence to show that the parasitoids would be less affected by JH-based insecticides than would the target species, their host. However, Wright and Spates (1972) recently reported that two JH analogs, while active against pupae of the stable fly,Stomoxys calcitrans(L.), did not affect development or subsequent reproduction of the hymenopteran parasiteMuscidifuraxraptor Girault and Sanders in the treated pupae. Similarly, Wilkinson and Ignoffo (1973) demonstrated that a JH analog which affects the target hostPieris rapae(L.) did not affect the developing endoparasiteApanteles rubeculaMarshall.In 1972, I conducted laboratory experiments to assess the survival of parasitoids in JH-treated spruce budworm, and now present the results.

ISSN:1754-5692    

DOI:10.1093/ee/3.2.361

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Insect parasitoids are known to exhibit habitat preferences during host-searching activities. For example, the polyphagous tachinid,Compsilara concinnata(Meigen) attacked larvae ofAcromycta acerisL. (Lepidoptera: Noctuidae) less often on isolated trees than on trees in clumps (Schwenke 1958). Also,Brachymeria intermedia(Nees) (Hymenoptera: Chalcididae) parasitized gypsy moth pupae at ground level in a defoliated area and not in an adjacent shaded area (Leonard 1971). In non-defoliated forests this parasitoid was found to parasitize pupae only near the tops of trees (Weseloh 1972).

ISSN:1754-5692    

DOI:10.1093/ee/3.2.363

出版商:Oxford University Press    

年代:1974

数据来源: OUP