Examples of Potential Risks from BBTs

Source: Office of Technology Assessment, U.S. Congress, 1995; Chapter 4, page 71

BBT examples

Potential environmental impacts

Potential human health effects

Conservation of natural enemies Probably insignificant No known risk (no known risk indicates that risks have not been documented. In some cases, the absence of document effects may be due to a lack of monitoring or observation.)
Classical biological control/ introduction of new natural enemies Some adverse impacts on nontarget organisms; destabilization of existing control by predators and parasites; habitat destruction; possible evolutionary changes. Many of these risks are shared by other BBTs. No known risk
Release of sterile fishes for biological control Adverse effects on nontarget organisms; potential for hybridization with wild forms; possible development of resistance, self-reproducing strains, or selective mating patterns; potential transmission of parasites No known risk.
Augmentative releases of parasites and predators Some risks similar to those for classical biological control; contamination of field-harvested natural enemies by parasites; depletion of natural enemies in collection sites. Allergic reactions among workers in insectaries
Phermones Potential adverse impacts on aquatic invertebrates and some fish from lepidopteran varieties but warning labels advise against such usage; other types of phermones may have greater potential toxicity to mammals, fish, birds; undocumented possibility for disruption of mating behavior of other insects; slight risk of resistance. Low oral or inhalation toxicity, possible dermal and eye irritation from lepidopteran-active products; higher toxicity among other phermone groups, but minimal human exposure.
Bacterial pathogens
(microbial pesticides)
Some adverse impacts on nontarget lepidoptera and their avian predators. Short-term declines in certain nontarget insects; resistance documented in field populations of pests treated regularly with Bt. Minimal risk to general population; some data suggest possible infection of immunocompromised individuals.
Viral pathogens
(microbial pesticides)
Minimal effects on nontarget organisms; possibility of resistance in future as field use expands. No known risk
Fungal pathogens
(microbial pesticides)
Possible effects on nontarget organisms; early evidence of resistance Some established human allergens and toxic metabolites
Protozoan pathogens
(microbial pesticides)
Possible effects on nontarget species No known risk
(microbial pesticides)
Possible effects on nontarget organisms particularly those in the soil. No known risk
Release of sterile insects Some adverse effects on nontarget organisms; possible development of resistance, self-producing strains, or selective mating patterns. No known risk

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