Small scale-up validation for ionizing radiations against Helicoverpa armigera larvae

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an economically important pest, which harms various kinds of important agricultural crops, such as cotton and paprika. Effects of ionizing radiation (gamma, x-ray, and electron beam radiation) at 300Gy on 4th to 5th instar larvae of H. armigera were tested on the post-treatment development of the larvae to identify the effective quarantine treatment dose. A few adults emerged out of the pupae developed from larvae irradiated with gamma ray and electron beams, while no adults emerged from the larvae irradiated with x-rays. Mortalities caused by gamma, X-ray, and electron beam radiation were 99.05%, 100%, and 99.93%, respectively, with no significant difference from that caused by methyl bromide (MeBr) fumigation (99.83%). Our results indicate that ionizing radiation could be recommendable as an alternative to MeBr and a phytosanitary treatment for quarantine. A treatment dose of 300Gy is adaptable as a quarantine treatment to H. armigera larva in paprika fruit for prevention of pupation and adult emergence. [Display omitted] •Ionizing radiation (gamma ray, electron beam, and X-ray at 300Gy) effectively inhibited development of H. armigera larvae.•The ionizing treatment showed the same effect as methyl bromide fumigation.•Ionizing radiation is recommendable as an alternative to methyl bromide for quarantine use.•A treatment dose of 300Gy is adaptable as a quarantine treatment to H. armigera larvae.