NUCLEAR POLYHEDROSIS VIRUS TRANSMISSION BY MICROPLITIS CROCEIPES (HYMENOPTERA: BRACONIDAE) ADULT FEMALES REARED IN INFECTED HELIOTHIS VIRESCENS (LEPIDOPTERA: NOCTUIDAE) LARVAE1,2

1989 ◽  
Vol 24 (4) ◽  
pp. 500-506 ◽  
Author(s):  
S. Y. Young ◽  
W. C. Yearian
Keyword(s):  
Heliothis Virescens ◽  
Nuclear Polyhedrosis Virus ◽  
Virus Transmission ◽  
Microplitis Croceipes ◽  
Control Group ◽  
Single Plant ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis ◽  
Lepidoptera Noctuidae ◽  
Cage Test

Heliothis nuclear polyhedrosis virus (HNPV) transmission by Microplitis croceipes (Cresson) [Hymenoptera: Braconidae] that emerged from HNPV-infected Heliothis virescens (F.) (Lepidoptera: Noctuidae) larvae was investigated in the laboratory and in single plant cage tests on field grown soybean. In the laboratory a small percentage of the M croceipes adults (13.3%) from infected larvae transmitted Heliothis HNPV. The mortality from HNPV in larvae exposed as late second instars to female parasitoids was 20.0%. In a single plant cage test on soybean conducted in the field, however, the percentage of mortality from HNPV in larvae did not differ significantly from that in the control group. When larvae were caged with females that had been artificially contaminated with HNPV up to 79.2% of the H. virescens larvae died of HNPV.

NUCLEAR POLYHEDROSIS VIRUS TRANSMISSION IN MULTIPLE GENERATIONS OF ANTICARSIA GEMMATALIS (LEPIDOPTERA: NOCTUIDAE) CAGED ON SOYBEAN

1989 ◽  
Vol 24 (1) ◽  
pp. 133-141
Author(s):  
S. Y. Young ◽  
W. C. Yearian
Keyword(s):  
Nuclear Polyhedrosis Virus ◽  
Larval Mortality ◽  
Virus Transmission ◽  
Anticarsia Gemmatalis ◽  
Velvetbean Caterpillar ◽  
Larval Population ◽  
Multiple Generations ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis ◽  
Lepidoptera Noctuidae

Transmission of a nuclear polyhedrosis virus (AgNPV) of the velvetbean caterpillar, Anticarsis gemmatalis Hübner, in multiple generations on caged soybeans was examined. Introduction of primary infected larvae into larval populations on soybean resulted in low levels of mortality in the initially uninfected population in generation one. Larval mortality levels increased in succeeding generations and were higher in treatments with greater larval population density. The increase in epizootic development was much less, however, when the plants were not infested for one larval generation. AgNPV concentrations on foliage and in soil generally reflected the mortality levels from AgNPV in the respective treatments.

Movement of Nuclear Polyhedrosis Virus into Velvetbean Caterpillar (Lepidoptera: Noctuidae) Larval Populations on Soybean by Nabis roseipennis (Heteroptera: Nabidae) Nymphs

1992 ◽  
Vol 27 (2) ◽  
pp. 126-134 ◽  
Author(s):  
S. Y. Young ◽  
W. C. Yearian
Keyword(s):  
Nuclear Polyhedrosis Virus ◽  
Larval Mortality ◽  
Anticarsia Gemmatalis ◽  
Velvetbean Caterpillar ◽  
Nabis Roseipennis ◽  
Polyhedrosis Virus ◽  
Soybean Plants ◽  
Nuclear Polyhedrosis ◽  
Mixed Age ◽  
Lepidoptera Noctuidae

Nabis roseipennis Reuter nymphs that preyed on larvae of the nuclear polyhedrosis virus (NPV) infected velvetbean caterpillar, Anticarsia gemmatalis (Hübner), excreted the virus (AgNPV) for several days thereafter. Based on bioassays, fifth instar and second instar nymphs excreted 84.7 × 105 and 9.7 × 105 polyhedral inclusion bodies (PIB) per nymph, respectively. The AgNPV-contaminated nymphs effectively disseminated the virus via the feces over soybean plants where it served as inoculum to initiate disease in larval populations of A. gemmatalis caged in the field. Larval mortality from AgNPV ranged from 11.4 to 48.5% over treatments in two tests. Larval mortality in treatments where the source of virus inoculum was AgNPV-contaminated fifth instar nymphs was similar to that in treatments where the source of viral inoculum was diseased larvae. Larval mortality resulting from AgNPV dissemination by the nymphs was usually higher in treatments containing fifth instar nymphs than in those with second instar nymphs. Dissemination of NPV by fifth instar nymphs was higher in mixed-age than in uniformed-age A. gemmatalis larval populations. This was not the case with the smaller second instar nymphs.

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