Résumé
BACULOVIRUSES provide alternatives to chemicals for controlling insect pests1–4 and can be applied by spraying. Baculoviruses have a limited host range, but work relatively slowly. They are dissolved in the midgut of insect larvae to release infectious virions which enter gut epithelial cells and begin to replicate. Replication in other organs causes extensive tissue damage and eventually death. This process can take 4–5 days, but in the field may last for more than a week, allowing the larvae to feed for longer and thereby damaging the host plant. Baculovirus expression vectors expressing foreign genes5,6, such as those for insect-specific toxins, hormones or enzymes, might alleviate this problem7–11 . We have now constructed a recombinant baculovirus derived from Autographa californica nuclear polyhedrosis virus containing an insect-specific neurotoxin from the venom of the North African (Algerian) scorpion, Androctonus australis Hector12. The neurotoxin acts by causing specific modifications to the Na+ conductance of neurons, producing a presynaptic excitatory effect leading to paralysis and death15,16; it has no effect in mice17,18. Expression of the neurotoxin by the virus causes a reduction in the time required to kill the host insect.