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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #413134
Research Project: Ecologically Sustainable Approaches to Insect Resistance Management in Bt Cotton

Location: Southern Insect Management Research

Title: Efficacy of 16 nucleopolyhedrovirus isolates toward Helicoverpa arntigera, Spodoptera litura, and Trichoplusia ni in Sri Lanka

Author
item KULASINGHE, KAUMADIE - University Of Peradeniya
item NISHANTHA, PRABATH - Horticultural Crops Research And Development Institute - Hordi
item HARRISON, ROBERT - US Department Of Agriculture (USDA)
item HEMACHANDRA, K. S. - University Of Peradeniya
item NUGALIYADDE, LIONEL - University Of Peradeniya
item Perera, Omaththage

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2025
Publication Date: 10/2/2025
Citation: Kulasinghe, W.M.N.K.K, Nishantha, K.M.D.W.P., Harrison, R.L., Hemachandra, K.S., Nugaliyadde, L., Perera, O.P. 2025. Efficacy of 16 nucleopolyhedrovirus isolates toward Helicoverpa arntigera, Spodoptera litura, and Trichoplusia ni in Sri Lanka. Southwestern Entomologist. 50 (4):1323-1348. https://doi.org/10.3958/059.050.0408.
DOI: https://doi.org/10.3958/059.050.0408

Interpretive Summary: Nucleopolyhedrovirues (NPV) or baculoviruses are narrow-range pathogens of insects and other arthropod species. NPVs are widely used as biopesticides to manage crop pests. In this study, 14 NPV isolates recovered from Helicoverpa species and two commercial isolates were evaluated against Helicoverpa armigera, Spodoptera litura, and Trichoplusia ni collected in Sti Lanka. Five NPV isolates with the highest efficacy (lowest LC50) against H. armigera were selected for field evaluation. The NPV isolates with the highest virulance included the commercial strains Biotrol Texas USA and Gemstar Lot#35022 and the H. armigera NPV isolates 3154 Russia, 1072 China, and 1623 India. NPV isolates 1072 China and 1623 India expressed the highest efficacy against H. armigera on tomato plants under field conditions in Sri Lanka. These NPV isolates exhibited little to no virulence against larvae of S.litura in laboratory bioassays. Inoculation of second instar larvae of T. ni with 3154 Russia resulted in 100 % mortality.

Technical Abstract: Numerous nucleopolyhedrovirus (NPV) strains discovered worldwide have been used as biopesticides extensively to manage crop pests. Different isolates of NPVs have exhibited variations in their genetics, pathogenicity, and field efficacy. The efficacy of 16 NPV isolates identified from Helicoverpa species was evaluated against Helicoverpa armigera, Spodoptera litura, and Trichoplusia ni collected in Sri Lanka. In laboratory bioassays, LC50 estimates varied over an approximately 2-fold range, with five NPV isolates (Biotrol Texas USA, Gemstar Lot#35022, 3154 Russia, 1072 China, and 1623 India) demonstrating higher virulence than other NPV isolates against H. armigera second instar larvae. These five isolates were selected and evaluated for their capacity to control H. armigera in field trials. Isolates 1072 China and 1623 India expressed the highest efficacy against H. armigera on tomato plants under field conditions. The isolates exhibited little to no virulence against larvae of S. litura in laboratory bioassays, while inoculation with 3154 Russia resulted in 100 % mortality in T. ni 2nd instar larvae within 10 days. The negative traits of NPV bio-pesticides such as slow speed of kill and limited host range can be overcome by selecting the most suitable isolate. The application of NPV biopesticides at the initial stage of pest infestation, under suitable environmental conditions, and multiple times can ensure higher pest control efficacy.