A diagnostic or control composition is useful to characterize or control insects and comprises a nucleotide sequence coding for juvenile hormone esterase (JHE). The coding sequence may be combined with a promoter sequence regulating the transcription thereof in a recombinant expression vector for use in controlling insects having a juvenile hormone esterase dependency. Preferred embodiments of the invention are recombinant baculoviruses in which a mutated JHE coding sequence provides relatively rapid speed of kill in insects.
