Simple methods to devitalize eggs and larvae of Heliothis virescens and Helicoverpa zea under laboratory conditions

Authors: BLANCO, CARLOS - University Of New Mexico; FINKENBINDER, CHAD - Benzon Research Inc; MORRIS, ASHLEY - Benzon Research Inc; BLENDERMAN, DANIEL - Benzon Research Inc; Portilla, Maribel

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2018
Publication Date: 9/30/2018
Citation: Blanco, C., Finkenbinder, C., Morris, A., Blenderman, D., Portilla, M. 2018. Simple methods to devitalize eggs and larvae of Heliothis virescens and Helicoverpa zea under laboratory conditions. Southwestern Entomologist. 43(3):563-569. https://doi.org/10.3958/059.043.0301.
DOI: https://doi.org/10.3958/059.043.0301

Interpretive Summary: Standard operating procedures for laboratory research with insects must include methods to address the proper disposal of these organisms. Commercial synthetic or natural insecticides are the “logical” way to devitalize insects, but their use in a laboratory may be a source of contamination that can affect rearing insects in the same facility. Insects are notorious for the great variation of environmental conditions they can withstand, so any attempt to propose a single method to devitalize them will be limited because of the vast diversity of Insecta. In order to ensure that insects are thoroughly devitalized before they are removed from laboratory confinement, researchers most commonly employ methods such as ultra-low freezing or autoclaving. These methods can be costly in both space and expense. As an alternative, we present several simple techniques to achieve complete devitalization of H. virescens and H. zea eggs and L1 larvae.

Technical Abstract: Heliothine moths are economically damaging insect pests, having a significant annual effect on world crop production. Several species within this subfamily are commonly used in agricultural research laboratories. Research protocols should include methods to ensure that excess individuals are completely devitalized before being discarded, preventing further spread of these pests. Processes such as ultra-low temperature freezing, autoclaving, or holding insects under adverse conditions for a long period of time are all commonly employed devitalization methods. Each of these methods add significant amounts of time and cost; also increasing competition for space in already crowded laboratories. While these frequently used methods may be necessary for some extremely resilient species, other species can succumb under less elaborated methods of devitalization. One hour exposure to undiluted household bleach, brief exposure (>20 seconds) of wetted individuals to microwave radiation, storage in a household freezer for 48 hours, and contact with 70% isopropyl alcohol for 24 hours, all completely devitalized eggs and L1 larvae of the corn earworm and the tobacco budworm. These highly effective methods may also be applicable to other noctuid species.