Home · Site Index · Search · People · Help











 


 
 

Issue: Impact on non-target organisms

There has been much media attention given to the potential impact of GM crops on non- target organisms. An ideal pest control tactic would be one that controls the pest, but does not harm other non-target organisms in any way. Non-target organisms include all organisms except for the pest to be controlled.  Examples of non-target organisms would be mammals, fish, birds, reptiles and other insects.

Examples of non-target insects to be protected include lady beetles, lacewings, and other insect predators, honey bees and other insect pollinators, and butterflies and other aesthetically pleasing insects.

Lady Beetle
Lady Beetle

Lacewing
Lacewing

Monarch
Monarch

Media attention has focused on Bt-corn and the impact that it may have on monarch butterflies. At one time, some believed that Bt plants would be the idea control of some crops pests, because only the pests that fed on the plant would ingest the toxin and the toxin is only toxic to some plant feeding insects. However, some Bt-corn plants have relative high levels of the Bt protein in their pollen, and pollen released from these plants may fall on other plants and be eaten by other insects that are not pests. In the case of the monarch caterpillars, pollen from the Bt corn drifts onto milkweed plants which are common in and near corn fields. As the monarch feeds on the milkweed leaves, it ingests the Bt pollen and some caterpillars are killed.

Effects on non-target organisms is and will continue to be an important issue. New GM crops will need to be evaluated for their potential effects on non targets. However, a double standard has arisen for regulating non target effects, one for insecticides and the other for GM crops. Many of the insecticides used today are considered broad spectrum- meaning they kill a wide range of insects including beneficial ones. Many are classified as Restricted Use Pesticides due to their toxicity to fish, birds, or other wildlife. Relative to most insecticides on the market, Bt-crops are more selective and potentially less damaging to non-target organisms.

Impacts of Bt cotton and corn on non-target arthropods