Notes on larval instars and adult antennae of Neodiprion abietis (Hymenoptera: Diprionidae)

Li, S.Y.

doi:10.4039/n03-044

“…In the laboratory, less than 1-d-old second, third, fourth, or Þfth instars were tested to determine larval susceptibility to the virus. Larval stages were determined according to characteristics of the size and color of their body and head capsule (Li 2003).…”

Section: Methodsmentioning

confidence: 99%

“…N. abietis is univoltine and overwinters in the egg stage. In Newfoundland, overwintering eggs hatch between late June and early July (Carroll 1962, Li 2003. Larvae actively feed on old foliage (Ն1 yr old) for Ϸ5 to 6 wk in the summer.…”

mentioning

confidence: 99%

Virulence of a Nucleopolyhedrovirus to Neodiprion abietis (Hymenoptera: Diprionidae)

Li¹

2005

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Different larval stages of balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae), were challenged by different concentrations of a nucleopolyhedrovirus in the laboratory to determine larval susceptibility to the virus and to test treatment effects of the virus on the sawfly survivors. The results indicated that younger larvae were more susceptible to the virus than older instars. The speed of larval death depended on the larval age and the virus concentration. Generally, the virus killed second or third instars in approximately 5 d and fourth or fifth instars in 10-12 d at concentrations of 10(7) polyhedral inclusion bodies (PIB) /ml. The virus had profound treatment effects on sawfly survivors. Feeding activity of the survivors was reduced by > 40% compared with that of the control group, pupal weight by approximately 25%, and adult emergence by > 30%. There was also a higher percentage of male adults in the virus-treated groups than in the control.

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“…However, virus yield per dead larva was not reported in this article. There are Þve instars in the larval stage of N. abietis in Newfoundland (Li 2003). Which instar is the most suitable stage for maximum virus production is not known.…”

mentioning

confidence: 99%

Influence of Larval Stage and Virus Inoculum on Virus Yield in Insect Host Neodiprion abietis (Hymenoptera: Diprionidae)

Li¹,

Skinner²

2005

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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, third, fourth, or fifth instar) with two virus concentrations (10(5) polyhedral inclusion bodies (PIB) /ml or 10(7) 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(7) PIB, depending upon larval age and virus concentration of inoculation. 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.

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Virulence of a Nucleopolyhedrovirus to Neodiprion abietis (Hymenoptera: Diprionidae)

Li

¹

2005

Journal of Economic Entomology

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Different larval stages of balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae), were challenged by different concentrations of a nucleopolyhedrovirus in the laboratory to determine larval susceptibility to the virus and to test treatment effects of the virus on the sawfly survivors. The results indicated that younger larvae were more susceptible to the virus than older instars. The speed of larval death depended on the larval age and the virus concentration. Generally, the virus killed second or third instars in approximately 5 d and fourth or fifth instars in 10-12 d at concentrations of 10(7) polyhedral inclusion bodies (PIB) /ml. The virus had profound treatment effects on sawfly survivors. Feeding activity of the survivors was reduced by > 40% compared with that of the control group, pupal weight by approximately 25%, and adult emergence by > 30%. There was also a higher percentage of male adults in the virus-treated groups than in the control.

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Notes on larval instars and adult antennae of Neodiprion abietis (Hymenoptera: Diprionidae)

Cited by 4 publications

References 1 publication

Virulence of a Nucleopolyhedrovirus to <I>Neodiprion abietis</I> (Hymenoptera: Diprionidae)

Virulence of a Nucleopolyhedrovirus to <I>Neodiprion abietis</I> (Hymenoptera: Diprionidae)

Influence of Larval Stage and Virus Inoculum on Virus Yield in Insect Host <I>Neodiprion abietis</I> (Hymenoptera: Diprionidae)

Virulence of a Nucleopolyhedrovirus to Neodiprion abietis (Hymenoptera: Diprionidae)

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