Development of a recombinant baculovirus expressing a modified juvenile hormone esterase with potential for insect control

Baculovirus insecticides are receiving renewed attention as insect pest control agents following the development of fast‐acting recombinant baculoviruses. Here we report on the construction and biological activity of a recombinant baculovirus derived from the nuclear polyhedrosis virus of Autographa californica which expresses a modified form of juvenile hormone esterase (JHE). The serine at the catalytic site of the JHE has been mutated to a glycine residue so that the protein does not degrade JH. The recombinant baculovirus expressing this modified form of JHE, named AcJHE‐SG, has enhanced activity against lepidopteran larvae. Lethal times of the recombinant are 20 to 30% lower than for the wild type virus, and a 66% reduction in feeding damage caused by infected larvae is observed. This result is comparable to the best recombinant baculovirus developed to date, AcAaIT, which expresses an insect‐selective scorpion toxin. The potential of these recombinant viruses for commercialization as insecticides is discussed. Bioassays of AcJHE‐SG in conjunction with anti‐JH agents indicate that the virus is not killing by an anti‐JH mechanism. Larvae apparently die from contraction‐paralysis, or disruption of the normal sequence of events at the molt. © 1995 Wiley‐Liss, Inc.