Formalin treatment of pupae of Copris hispanus L. (Coleoptera: Scarabaeidae) as a basis for release from quarantine.
The effects of dipping C. hispanus pupae in reverse osmosis (RO) water, 1% formaldehyde (about 3% formalin), 1% formaldehyde + 1% Tego 51 detergent mixtures, and 1% glutaraldehyde (Wavicide), each for 3 min, followed by serial rinsing in RO water were investigated as a basis for the release of insects from quarantine. Of the pupae dipped in water, 70.8% survived to be fully pigmented adult beetles as opposed to 62.5% of those dipped in 1% formaldehyde. All pupae dipped in either 1% glutaraldehyde, or 1% formaldehyde + 1% Tego 51 detergent mixture failed to eclose. Survival of pupae dipped in water or 1% formaldehyde appears to be greater in those pupae dipped after having completed >50% of their development. There was no evidence of delayed mortality associated with dipping in 1% formaldehyde, although time to eclosion was reduced and the frequency of deformed beetles was higher. Severely deformed beetles only survived for a few days after eclosion.