Canadian Forest Service Publications

Influence of larval stage and virus inoculum on virus yield in insect host Neodiprion abietis (Hymenoptera: Diprionidae) 2005. Li, S.Y.; Skinner, A.C. Journal of Economic Entomology 98(6): 1876-1879.

Year: 2005

Issued by: Atlantic Forestry Centre

Catalog ID: 25974

Language: English

CFS Availability: Order paper copy (free)

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Abstract

Virus yield produced by dead larvae of balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae), that had been infected at four different larval stages (second, thir, fourth, or fifth instar) with two virus concentrations (10 to the fifth power polyhedral inclusion bodies (PIB)/ mL or 10 to the 7th power PIB/mL), were analyzed and compared to determine the effects of instar and amount of virus inoculum on virus production. The results indicate that both larval stage and inoculation dosage significantly affect virus yield. On average, each dead larva produced 1.36-12.21 x 10 to the 7th power PIB, depending upon larval age and virus concentration of inoculum. Although each dead larva produced more PIB when it was inoculated in the fourth or fifth stage, inoculation of these larvae did not result in the highest virus yield because of low larval mortality. In terms of net virus return, third instars would maximize virus yield when they are inoculated with a virus concentration that can cause 95-100% larval mortality.