1Division of Genomic Resources, ICAR-National Bureau of Agricultural Insect Resources, Hebbal-560 024, Bengaluru, India
2Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India
3Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India
4Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India
*Corresponding Author: M. Mohan, Division of Genomic Resources, ICAR- National Bureau of Agricultural Insect Resources, Hebbal-560 024, Bengaluru, India, Email: mohan_iari@yahoo.com
**M. Shanthi, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore-641003, Tamil Nadu, Indiamshanthiento@tnau.ac.in, Orcids: https://orcid.org/0009-0002-6300-9558; https://orcid.org/0000-0001-5737-4781; https://orcid.org/0000-0001-5571-3946; https://orcid.org/0000-0002-7485-1153; https://orcid.org/0009-0001-5610-5034; https://orcid.org/0000-0001-6169-7823; https://orcid.org/0000-0001-7444-9343; https://orcid.org/0000-0002-6764-5167; https://orcid.org/0000-0002-2327-6988
Online published on 22 July, 2025.
Maruca vitrata, commonly known as the legume pod borer, is a significant pest affecting leguminous crops like cowpea, pigeon pea, lab lab, beans, mung bean and others across tropical and subtropical regions. It severely reduces yields by boring into flowers, pods and seeds, causing significant damage. Field control failures with insecticides have been experienced by farmers due to development of insecticide resistance upon over reliance on insecticides. Hence, the present study attempted to quantify the levels of insecticide resistance and their detoxification routes in field collected populations of M. vitrata from intensive legume growing regions of India.
In this study, a survey was conducted in intensive legume-growing regions of India to collect field populations of M. vitrata in 2024. Dose mortality bioassays were conducted against five commonly used insecticides (quinolphos, chlorantraniliprole, chlorpyrifos, flubendimide, indoxacarb) and resistance ratios were determined by comparing the LC50 values of field populations with the susceptible laboratory population. Enzyme assays were performed to evaluate the role of detoxifying enzymes like cytochrome p 450s, glutathione S-transferases and carboxylesterases in conferring resistance.
The resistance ratios varied from 56.48 to 311-fold for quinolphos, 3.84 to 97-fold for chlorantriniliprole, 15.76 to 92.088-fold for chlorpyrifos, 30.86 to 75.26-fold for flubendimide and 33.21 to 82.95-fold for indoxacarb. The activities of detoxification enzymes were significantly higher in the midgut of field collected M. vitrata larvae. The data suggests rational use of various insecticides in rotation so as to delay the further development of resistance in M. vitrata.
Detoxification enzymes, Insecticide resistance, LC50, Maruca vitrata
