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United States Department of Agriculture

Agricultural Research Service

Title: Rate of Larval Lysis and Yield and Activity of Inclusion Bodies Harvested from Trichoplusia Ni Larvae Fed a Wild-Type Or Recombinant Isolate of the Nuclear Polyhedrosis Virus of Autographa Californica

item Ignoffo, Carlo
item Garcia Jr, Clemente

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 26, 1996
Publication Date: N/A

Interpretive Summary: Genetically engineered, recombinant viruses are being developed to increase the field effectiveness of these safe microbial insecticides. We wanted to know how much residual virus might be left in the environment after larvae infected with either the recombinant or wild-type virus had died. Our research demonstrated that there was 1.25 to 2.42 times more virus produced din wild-type infected larvae than in larvae infected with the recombinant virus. Because more recombinant infected-larvae than wild-virus infected larvae are expected to fall intact to the ground and lyse this could result in a more rapid environmental buildup of recombinant PIB in the soil. These results could help scientists exploring the potential environmental impact of field use of recombinant viral insecticides.

Technical Abstract: Larvae of the cabbage looper, Trichoplusia ni, infected with a wild-type parental, isolate (AcC6) of the nuclear polyhedrosis virus of Autographa californica, produced 1.25 to 2.42 times more virus then larvae infected with a recombinant strain (AcAaIT). The AcAaIT isolate was genetically engineered to express an insect-selective toxin from the Algerian scorpion, ,Androctonus australis. Yields of viral polyhedral inclusion bodies (PIB), based on PIB/mg larva, were 1.12 to 1.43 times higher with AcC6 than with AcAaIT. Although AcAaIT-infected larvae produced fewer PIB than AcC6-infected larvae there was no difference in in vivo activity of the virus between the two strains. Also, there was no difference between the strains in the elapsed time from larval death to larval lysis. The potential ecological-environmental impact of the use of recombinants on subsequent viral amplification and persistence and its relationship to wild-type viruses is discussed.

Last Modified: 4/22/2015
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