Field testing a genetically modified baculovirus

Baculoviruses (NPVs) are invertebrate-specific pathogens of which over 500 isolates/species have been documented to date. invertebrate specificity offers a clear advantage toward development of specific environmentally compatible insecticides. Toward this end, several wild-type NPVs have been registered and used commercially with limited success. The key disadvantage to their broader application is the time required to kill the target species which in some cases may take a week or more. A promising approach to remedy this problem is the insertion of genes encoding insect-specific toxins into the NPV genome. Scientists at American Cyanamid successfully inserted the insect-specific toxin gene from the scorpion Androctonus australis Hector (ie., AaHIT) into the EGT gene deleted NPVs of Autographa californica Speyer (AcNPV) and Helicoverpa tea (Boddie) (ie., HzNPV). Laboratory and greenhouse studies show that incorporation of the gene changes the viral mode-of-action enabling it to kill its host 2-3 times faster than the wild-type. However, the true test of commercial potential is efficacy in the field. Releasing a genetically engineered microorganism in the field presents special concerns from both a public perception and a scientific aspect. American Cyanamid scientists were successful in meeting both challenges and conducted field trials in the U.S. with the Acal-AaHIT construct in both 1995 and 1996.