The Ripple Effect: Assessing the Impact of Multi-walled Carbon Nanotubes on the Parasitization Efficacy of Trichogramma chilonis (Hymenoptera: Trichogrammatidae)
Deepa Bhagat
*
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India.
Shilpa Sharma
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India and Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, Chatha 180009, Jammu and Kashmir, India.
Manav Pandotra
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India and Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, Chatha 180009, Jammu and Kashmir, India.
Ujjwal Parotra
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India and Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, Chatha 180009, Jammu and Kashmir, India.
Yashvi Nayyar
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India and Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, Chatha 180009, Jammu and Kashmir, India.
B. C. Sharma
Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, Chatha 180009, Jammu and Kashmir, India.
P. Krishnamoorthy
ICAR -National Institute of Veterinary Epidemiology and Disease Informatics P.B. NO. 6450, Yelahanka, Bengaluru 560064, Karnataka, India.
Duleep Kumar Samueld
ICAR- Indian Institute of Horticultural Research, Ivar Kandapura, Bengaluru 560088, Karnataka, India.
S. K. Arun
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India.
G. T. Chaithrama
Indian Council of Agricultural Research - National Bureau of Agricultural Insect Resources, P.B. No. 2491, H & A Farm post, Bellary Road, Bengaluru 560 024, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
Multi-walled carbon nanotubes (MWCNTs) are promising nanomaterials for agricultural applications because of their high surface area, exceptional mechanical strength, thermal stability, and unique physicochemical properties. Although MWCNTs have been widely investigated for enhancing plant growth, nutrient uptake, stress tolerance, and agrochemical delivery, information on their effects on beneficial arthropods remains limited. The present study evaluated the non-target effects of pristine MWCNTs (outer diameter <8 nm; length 10–30 µm) on the egg parasitoid Trichogramma chilonis (Hymenoptera: Trichogrammatidae), an important biological control agent. UV-sterilized Corcyra cephalonica eggs treated with MWCNTs (0.2 mg card⁻¹) were evaluated using Y-dual choice, eight-arm multiple-choice, and no-choice olfactometer assays under laboratory conditions. Parasitization was assessed by counting blackened host eggs, and differences between treatment and control groups were analysed using an unpaired Student's t-test. MWCNT-treated egg cards exhibited significantly lower parasitization than untreated controls in the Y-dual choice (P = 0.0005), eight-arm multiple-choice (P = 0.0013), and no-choice (P = 0.0104) assays. Stereozoom microscopy revealed fewer parasitized host eggs on treated cards, while scanning electron microscopy showed deformation of MWCNT-treated host eggs. These findings demonstrate that MWCNT exposure adversely affects host utilization and parasitization efficiency of T. chilonis. The study highlights the importance of evaluating the biosafety of nanomaterials toward beneficial insects before their widespread agricultural deployment and supports the inclusion of non-target risk assessments in the development of nanotechnology-based crop protection products.
Keywords: Multi-walled carbon nanotubes, Trichogramma chilonis, biosafety, non-target effects, egg parasitoid, olfactometer