Efficacy of chlorobenzene as a new fumigant for control of confused flour beetle (Coleoptera: Tenebrionidae) and rice weevil (Coleoptera: Curculionidae)

Authors: Liu, Yong Biao

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2025
Publication Date: 2/8/2025
Citation: Liu, Y.B. 2025. Efficacy of chlorobenzene as a new fumigant for control of confused flour beetle (Coleoptera: Tenebrionidae) and rice weevil (Coleoptera: Curculionidae). Insects. 16(2). Article 183. https://doi.org/10.3390/insects16020183.
DOI: https://doi.org/10.3390/insects16020183

Interpretive Summary: There is a need for safe and effective alternative treatments for postharvest pest control on fresh and stored products. Chlorobenzene is an industrial solvent and was used to manufacture pesticide DDT. We conducted laboratory fumigation tests with chlorobenzene against confused flour beetle and rice weevil and found chlorobenzene to be an effective fumigant against the two insects. Complete control of adults of both species was achieved in small scale fumigation tests. Complete control of all life stages of confused flour beetle and nearly complete control of all life stages of rice weevil were achieved in large-scale fumigations of 20 kg corn in a 60L chamber. Since chlorobenzene has low toxicity to mammals and is widely available at a low cost, it has potential to be a safe, effective, and economical alternative fumigant for postharvest pest control on stored products.

Technical Abstract: Chlorobenzene is an industrial chemical with relatively high vapor pressure and was used in the past to produce pesticide DDT (Dichlorodiphenyltrichloroethane). In this study, chlorobenzene was demonstrated to be an effective fumigant against two stored product insects, confused flour beetle (Tribolium confusum) and rice weevil (Sitophilus oryzae). In small scale fumigations in 1.9L glass jars, complete control of adults of both confused flour beetle and rice weevil was achieved in 24 h at a dose of 100 'l/l at 21'C. In large scale fumigations in a 60L chamber, all life stages of confused flour beetle and rice weevil in 20 kg corn was fumigated for 24 h with 30 ml (500 'l/l) chlorobenzene at 21'C. Complete control of adults and immature stages of confused flour beetle was achieved. For rice weevil, adults had 100% mortality and immature life stages had 97.8% mortality. These results demonstrated that chlorobenzene is effective as a fumigant against stored product insects, and it is technically feasible to conduct large-scale fumigations for postharvest pest control on stored products.