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A novel baculovirus observed to infect Automeris liberia (Cramer) (bullseye moth) is here described. Caterpillars of A. liberia with symptoms of viral infection were collected from African oil palm plantations in Tailândia, PA, Brazil. Macerated caterpillars were then offered to caterpillars of Automeris cinctistriga (Felder & Rogenhoper), leading to viral symptoms and death before pupation. A transmission electron microscope was used for virus ultrastructural identification. The presence of viral occlusion bodies (OBs) containing multiple nucleocapsids was observed and such features are compatible with Alphabaculovirus (Baculoviridae). Molecular detection by PCR with primers for polyhedrin gene (polh) and for late expression factor-8 gene (lef-8), confirmed that this isolate belonged to Alphabaculovirus genus. To our knowledge, this is the first record of a baculovirus isolated from or associated to Automeris. The name Automeris liberia nucleopolyhedrovirus (AuliNPV) is proposed for the new virus., (© 2022. Sociedade Entomológica do Brasil.)

The baculovirus Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) is pathogenic to Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) larvae, known as soybean looper, which is an important pest of soybean and bean. In this study, some parameters were tested to overcome the difficulties in the in vivo production of ChinNPV aiming to increase its use as a biopesticide. First, different combinations of larval instars (3rd and 4th instars), larval incubation temperatures (23 °C and 26 °C), and rearing densities (individually and 10 larvae/cup) were compared for larval weight and the production of occlusion bodies (OBs). A positive correlation (p< 0.001) was observed for OB production and larval weight. Fourth instar larvae produced more OBs than third instar larvae (p<0.05); however, no significant differences in OBs/larva (p>0.05) were observed for larvae kept in groups or individually. Therefore, a second assay was performed using fourth instar larvae incubated at 26 °C and two larval densities (10 larvae/cup and 40 larvae/cup). The losses of insects and OB production were evaluated as well as the influence of storage temperatures post-mortem (-20 °C, 4 °C, and 15 °C) in the OB yield. As expected, insect losses due to cannibalism or microbial contamination were greater (p<0.05) with the increase in larval density, although no difference was observed in OBs/larva (p>0.05). In addition, the storage temperature post-mortem did not influence the OB yield (p>0.05). The average production of ChinNPV OBs was 3×10 10 OBs/40 larvae cup. The results demonstrate the viability of rearing C. includens in groups to enhance the mass production and reduce virus production costs., (© 2021. Sociedade Entomológica do Brasil.)

Members of the family Baculoviridae have been quite successfully used as biocontrol agents against some lepidopterans. Likewise, a number of fungi are important natural enemies of these pests. An interesting approach to increase control efficacy could be the combination of a given nucleopolyhedrovirus (NPV) and a fungus, since they possess distinct modes of action. As a first step towards this goal, we assessed the interaction between NPV (either AgMNPV-79 or SfMNPV-6nd) and the entomopathogenic fungus Metarhizium rileyi (either CG1153 or CG381), using Anticarsia gemmatalis and Spodoptera frugiperda as hosts. In sequential applications of these pathogens, per os inoculation of an NPV (leaf discs with 2.5 × 10 4 occlusion bodies) either two days before or two days post-spraying of its counterpart fungal strain (5 × 10 3 conidia.cm -2 sprays) usually resulted in an antagonistic effect. When both pathogens were simultaneously applied at different combined dosages, usually an additive effect was seen. Interestingly, a number of dead larvae showing signs of co-infections (partially with soft integument and partially mummified) were recorded. However, mixes with lower dosages of both pathogens did not cause significantly higher insect mortalities compared to low dosages of the fungus applied alone. The advantages and disadvantages of the simultaneous applications of NPV and M. rileyi aiming at the management of either A. gemmatalis or S. frugiperda were discussed., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The baculovirus Condylorrhiza vestigialis multiple nucleopolyhedrovirus (CoveMNPV), isolated from C. vestigialis infected larvae in Paraná (Brazil), was identified in our laboratory. A full-length clone was obtained from the CoveMNPV genome, of the gene that encodes the homolog to baculoviral p74, essential for oral infectivity which was then sequenced and characterized. The CoveMNPV p74 gene (GenBank accession number EU919397) contains an ORF of 1935 bp that encodes a deduced protein of 73.61 kDa. The phylogenetic affiliations of the CoveMNPV gene were determined by a heuristic search of 40 aligned baculovirus p74 nucleotide sequences using maximum parsimony (PAUP 4.0b4a). The phylogenetic analysis placed CoveMNPV within lepidopteran nucleopolyhedrovirus (NPV) Group I, Clade A, as being the closest to Choristoneura fumiferana defective NPV.

A baculovirus was isolated from larvae of Condylorrhiza vestigialis (Guenée) (Lepidoptera: Crambidae), a pest of a forest species known as Poplar (family Salicaceae, genus: Populus) with high economic value. Electron microscopy analysis of the occlusion body obtained from diseased larvae showed polyhedra containing multiple nucleocapsids per envelope. This baculovirus was thus named Condylorrhiza vestigialis multiple nucleopolyhedrovirus (CoveMNPV) and characterized by its DNA restriction endonuclease pattern, polyhedral protein, viral protein synthesis, and infectivity in insect cell lines. Restriction endonuclease profiles of viral DNA digested with five restriction enzymes were obtained and the CoveMNPV genome size was estimated to be 81+/-2.5 kbp. The isolation of the polyhedra (OBs) was done from the crude extract of infected larvae by ultracentrifugation through sucrose gradients. These viral particles were analyzed by denaturing polyacrylamide gel electrophoresis (SDS-PAGE), which showed a strong band with approximately 33 kDa, corresponding to the main protein of the occlusion bodies (polyhedrin). Also, a similar band was observed for CoveMNPV infected Spodoptera frugiperda cells (SF-21 AE) pulse-labeled with [(35)S] methionine and fractionated by SDS-PAGE. Of the four insect cell lines tested for susceptibility to CoveMNPV infection, the SF-21 AE was the most susceptible with occlusion bodies produced in most of the inoculated cells. This is the first record of an NPV from C. vestigialis.

Anticarsia gemmatalis multicapsid nucleopolyhedrovirus (AgMNPV) is one of the most successful biological insecticides. In this study, we cloned and sequenced a 12.5 kbp BamHI-D restriction endonuclease fragment of the AgMNPV isolate 2D genome that includes the gp64 gene. We compared this highly conserved region with that of other baculoviruses. AgMNPV contained two genes, p22.2 and v-trex, in common with Choristoneura fumiferana MNPV (CfMNPV) that were not present in other baculoviruses. The v-trex gene has homology to a eukaryotic 3' repair exonuclease and appears to have been acquired from an invertebrate host. The v-trex gene product has the potential to be involved in virus recombination or UV-light tolerance. Multigene phylogenetic analysis suggested that AgMNPV is most closely related to Orgyia pseudotsugata MNPV (OpMNPV). AgMNPV differed from other group I NPVs in that ChiA and v-cath gene homologues were missing from the region downstream of the gp64 gene. Proteinase assays and genetic probes suggest the v-cath gene is absent from AgMNPV.

Anticarsia gemmatalis nuclear polyhedrosis virus (AgNPV; family Baculoviridae) is pathogenic for larvae of the velvetbean caterpillar, Anticarsia gemmatalis Hübner-an important pest of soybean. AgNPV is a viable alternative to chemical control of A. gemmatalis in Brazil, where its use as a pesticide has brought significant economic and environmental benefits. Although a significant amount of information is available on the ecological and biological control aspects of AgNPV, very little is known about the replication cycle and host specificity of this virus. We examined the susceptibility of four lepidopteran cell lines to AgNPV. Infections of the A. gemmatalis UFL-AG-286 cell line were highly productive. Ninety percent of infected cells had polyhedral inclusion bodies by 48 hr after infection, and the infectious virus titer was 10(8) IU/ml. Viral DNA replication was efficient, and the maximal rate of synthesis was between 6 and 12 hr after infection. Infections of the Spodoptera frugiperda IPLB-SF-21 cell line were productive but less efficient. Infections of Choristoneura fumiferana IPRI-CF-124T cells with this virus were poor, with only 5% of the cells forming polyhedra and an infectious virus titer of 10(6) IU/ml. The level of viral DNA replication was low, suggesting that this system was predominantly abortive. Infections of Bombyx mori BM-5 cell lines were abortive, and cells had apoptosis-like morphology. No polyhedra or increase in infectious levels were observed, and there was little or no replication of viral DNA. Our data suggest that restriction of AgNPV replication in abortive cell lines is due mainly to inability of viral DNA to replicate efficiently. The possible causes of low DNA replication are discussed. Our results suggest that the cell lines utilized in this study can provide an important model for studying mechanisms of AgNPV host specificity.