Related Experiment Video
Updated: May 8, 2026
Isolation and Selection of Entomopathogenic Fungi from Soil Samples and Evaluation of Fungal Virulence against Insect Pests
Published on: September 28, 2021
Selection of a nucleopolyhedrovirus isolate from Helicoverpa armigera as the basis for a biological insecticide
Maite Arrizubieta1, Trevor Williams, Primitivo Caballero
1Bioinsecticidas Microbianos, Instituto de Agrobiotecnología, CSIC-UPNA, Mutilva Baja, Navarra, Spain.
Background:
The cotton bollworm, Helicoverpa armigera, is an insect that causes damage in a wide range of crops in Spain. Seven isolates of H. armigera single nucleopolyhedrovirus (HearSNPV) from the Iberian Peninsula were subjected to molecular and biological characterization and compared with a Chinese genotype (HearSNPV-G4).
Results:
The estimated sizes of the Iberian genomes varied between 116.2 and 132.4 kb, compared to 131.4 kb of the HearSNPV-G4 reference genome. Phylogenetic analysis based on the lef-8, lef-9 and polh genes revealed that the Iberian strains were more closely related to one another than to other HearSNPV isolates. Occlusion body (OB) concentration-mortality responses (LC50 values) did not differ significantly among Iberian isolates when tested against a Helicoverpa armigera colony from Oxford (UK). Despite being the fastest killing isolate, HearSNPV-SP1 was as productive as isolates with lower virulence, with an average yield of 3.1 × 10(9) OBs larva(-1) . OBs of HearSNPV-SP1 and HearSNPV-G4 were similarly pathogenic against a recently established colony from southern Spain, although HearSNPV-SP1 was faster killing than HearSNPV-G4 against a range of instars.
Conclusion:
The insecticidal properties of HearSNPV-SP1 mean that this strain is likely to prove useful as the basis for a biological insecticide for control of Helicoverpa armigera in Spain.
