Fourteen species of parasitoids (13 hymenopterans, 1 dipteran) were reared from larvae or pupae of the obliquebanded leafroller, Choristoneura rosaceana (Harris), collected from commercial raspberry fields in the Fraser Valley, British Columbia, Canada, over 3 years. Levels of parasitism ranged from 5 to 15%. Among these 14 species, five represent new host records. A polyembryonic wasp, Macrocentrus nigridorsis Viereck (Hymenoptera: Braconidae), was the most abundant parasitoid. External feeding on the final host instar is obligatory for M. nigridorsis to complete development. On average, each parasitized host larva produced about 36 M. nigridorsis, in either unisexual or mixed-gender groups. Overall male to female sex ratio was 1:4. Head capsules of mature parasitized host larvae were significantly larger than those of unparasitized ones, suggesting that C. rosaceana larvae parasitized by M. nigridorsis might have an extra larval stage.

The Canadian Entomologist 131: 65 -70 (1999) Fifth-instar larval mortality was compared between male and female Choristoneura occidentalis Freeman exposed in the laboratory to sublethal doses of Choristoneura furniferana (Clem.) multicapsid nuclear polyhedrosis virus (CWNPV) with or without optical brighteners. More females than males died when the virus was used alone, but differences were not significant. When 1% brightener was added to CWNPV suspension, differences in larval mortality between males and females were significant for three of the four brighteners tested. In addition, times at which 50% of the larvae died indicated that female larvae died 23 and 39% more quickly than male larvae, respectively, when brightener Blankophor HRS and Tinopal LPW were added to the virus, whereas at times at which 95% of the larvae died indicated that females died 33 and 54% faster than males. Alteration of sex ratio favoring male survival can play a significant role in the biological control of C. occidentalis by the virus. Li, S.Y., et I.S. Otvos. 1999. Mortalit6 diffkrentielle chez des larves miles et femelles de Choristoneura occidentalis (Lepidoptera; Tortricidae) exposCes a un baculovims, avec ou sans dCcolorant optique. The Canadian Entomologist 131 : 65-70. La mortalit6 des larves de cinquikme stade a Ct C comparCe chez des mdles et des femelles de Choristoneura occidentalis Freeman exposCes en laboratoire B des doses sublktales du virus responsable de la polyhkdrose nuclkaire chez Choristoneura furniferana, le CWNPV, en prCsence ou en l'absence de dkcolorants optiques. La mortalit6 a atteint plus de femelles que de mgles en prksence du virus seul, mais les diffkrences n'Ctaient pas significatives. A l'addition de 1% de dCcolorant optique B la suspension de virus, les diffkrences entre la mortalit6 des larves mdles et celle des larves femelles sont devenues significatives pour trois des quatre dCcolorants utili-sCs. De plus, la valeur du LT,, a dCmontrC que les larves femelles sont mortes 23% plus rapidement que les mdles en presence du dCcolorant Blankophor HRS et 39% plus rapidement en prCsence du dCcolorant Tinopal LPW avec le virus. En tenant compte du LT9,, les femelles sont mortes 33 et 54% plus rapidement que les m2les en prCsence des mCmes dCcolorants. Une augmentation du rapport m2les:femelles favorisant la survie des msles peut jouer un r81e important dans la lutte biologique contre C. occidentalis au moyen du virus. [Traduit par la RCdaction]

The native balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae), occurs throughout Canada, Alaska, and the northern United States of America (Rose et al. 1994; Drooz 1985). This sawfly was originally described as Lophyrus abietis (Hymenoptera: Diprionidae) (Harris 1841), then transferred to the genus Diprion (Hymenoptera: Diprionidae) (MacGillivray 1916). Rohwer (1918) established the genus Neodiprion for Nearctic species of the genera Lophyrus and Diprion. Based on differences in size, color, and female genitalic characters between adults reared from the genera Abies, Picea, Pseudotsuga, and Tsuga (Pinaceae), Ross (1955) considered N. abietis as a complex. After a thorough morphological and physiological study, Knerer and Atwood (1972) concluded that there were five strains of N. abietis in North America: one western and four eastern.