none 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 or 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.