Biological control offers one of the most promising, environmentally safe, and sustainable control tactics for arthropod pests and weeds for application as part of an area-wide integrated pest management (AW-IPM) approach. Public support for biological control as one of the preferred methods of managing exotic and indigenous pests is increasing in many countries.
Augmentative biological control can complement the sterile insect technique to manage key insect pests. While sterile males affect the adult stage of the target pest, many natural enemies attack the immature stages and the action of both agents is often synergistic. Augmentative biological control can be integrated to the use of sterile insect releases in AW-IPM programmes for pest suppression, and/or the by-products from insect mass rearing facilities can be utilised in the production processes related to augmentative biological control programmes.
Use of ionizing radiation in biological control
Important constraints to the use of augmentative biological control such as costly production systems of biological control agents, and the presence of accompanying pest organisms during their shipment can be alleviated using ionizing radiation such as gamma rays and X-rays. The reduction of production and handling costs is achieved by expanding the period of host suitability, increasing shelf life, avoiding unnecessary sorting steps before shipment, etc. Ionizing radiation is also effectively applied to eliminate the risk of shipping fertile host or prey pest individuals or other hitchhiking pests.
Nuclear techniques can also help to reduce the risks associated with the introduction of exotic biological control agents as part of classical biological control, which can become pests of non-target organisms if not carefully screened under semi-natural or natural conditions.
Ionizing radiation is also a very useful tool to study host-parasitoid physiological interactions, such as host immune responses, by suppressing defensive reactions of natural or factitious hosts. Applied at a very low-dose, radiation may be used to stimulate reproduction of some entomophagous insects.
Additionally, ionizing radiation can be applied to semi- or completely sterilize hosts or prey for deployment in the field to monitor natural enemy populations or to increase the initial survival and build-up of natural or released biological control agents in advance of seasonal pest population growth.