Effectiveness of green cupric oxide nanoparticles for walnut storage pest management

RODRIGUEZ, M. R.; COMELLI, N.C.; LÓPEZ, T. E.; SÁNCHEZ MATÍAS, MARIANA DEL H.; DENETT, G. O.; BRACAMONTE, D. M.; PIETRO, DANIEL EDUARDO; DIEZ, P. A.; GONZALEZ-BARÓ, A. C.; SAMPIETRO, D. A.

Research Square 2024

Research Square 2024

Año: 2024 p. 1 - 20

Walnut yield and quality are often affected by beetle infestations, particularly those caused by Carpophilus dimidiatus (Fabricius) (Nitidulidae) and Oryzaephilus mercator (L.) (Silvanidae). Beetle damage exposes walnut to microbial food spoilers such as Fusarium species. Insecticides currently used for beetle control are environmentally unfriendly. Pest-suppressing nanomaterials can generate innovative nanopesticide technologies leading to more sustainable and efficient farming practices. This work explores a green synthesis approach for copper oxide nanoparticles (CuO-NPs) in basic medium by hydrolates obtained from Lippia integrifolia and Pimpinella anisum, denoted as CuO-I and CuO-A, respectively. Characterization through XRD, FT-IR, Raman, UV-Visible absorbance, and AFM techniques, indicated that CuO-A and CuO-I have a size ranging 2-10 nm height. Antifungal assay showed that both have a similar efficacy (MID = 320 µg), 3-fold stronger than CuO- NPs obtained in absence of hydrolates (denotes CuO-W) (MID = 960 µg), with the broadest inhibitory halos (ID = 126-128 mm) observed for CuO-A. Insecticidal activity of CuO-NPs showed a concentration-dependent behavior, with CuO-I showing an effect comparable to diatomaceous earth. SEM images confirm the adhesion of nanoparticles to insect surfaces, which could induce oxygen deprivation and disrupting of metabolic processes. Both CuO-A and CuO-I are promising for their use in integrated pest control in walnut storage.