Transmission of Different Nucleopolyhedroviruses by Two Ectoparasitoids – Bracon hebetor Say (Hymenoptera: Braconidae) and Euplectrus plathypenae (Howard) (Hymenoptera: Eulophidae)

Abstract

The transmission of nucleopolyhedroviruses (NPVs) of Autographa gamma (AgNPV),Mamestra brassicae (MbNPV), Lacanobia oleraceae (LoNPV), Helicoverpa armigera (HaNPV)and Xantia c-nigrum (XnNPV) to their relevant larvae by the ectoparasitoid Bracon hebetorand the transmission of the multiple-enveloped NPVs of Spodoptera exigua (SeMNPV) andSpodoptera frugiperda (SfMNPV) by the ectoparasitoid Euplectrus plathypenae was examined.Two methods of contamination of the both parasitoids (exposure to infected hostsand total body surface) and two subsequent transmissions of the viruses by Bracon hebetorto healthy hosts were tested. The results showed that both parasitoids were capable tobe mechanical vectors of the tested NPVs. Every Bracon hebetor female was able to transmitsubsequently twice the virus in 27% to 52.2% of the five Noctuidae species by preliminaryexposing to infected larvae. The second method of contamination (applying virus suspensionto the total body surface of the parasitoid) was also efficient causing virus infection inbetween 29.4% and 54.15% of the larvae.The parasitoid E. plathypenae transmited the virus from infected to noninfected larvaein 20% and 25.57% of the S. frugiperda and S. exigua larvae, and 6.43% and 11.10%, respectivelyof them died from the virus infection. The same observation was established by thesecond method of contamination – respectively 33.33% and 40% infection and between13.23% and 16.67% mortality. The mortality of all tested larvae exposed to virus contaminated parasitoids was higherwhen the parasitoid entire body surface had been artificially contaminated with the virusthan when the parasitoid itself was previously allowed to oviposit the larvae.

Keywords

• Hymenoptera
• Lepidoptera
• Nucleopolyhedroviruses
• Transmission