Report Reveals Bt risks to Insects and Soils (3/5/2007)

Report Reveals Risks to New Zealand's Insects and Soils
GE Free NZ press release, 3 May 2007

Plants containing "Bt" toxins could severely damage New Zealand soil, and beneficial insect populations, suggests a published review of international scientific studies.

The report by Hillbeck and Schmidt examines the published literature on Bt toxins widely incorporated as a feature of GM plants - in scores of laboratory feeding studies.

It shows a range of important insect species including bees, butterflies and moths can be fatally and chronically affected by Bt "Cry" genes. Lady birds had increased death rates after two weeks of eating one version of the toxins.

The studies also observed that Bt expressed in transgenic plants was far more detrimental to reproduction, growth and lifespan in important insect populations. Nontarget insects had a higher death rate from GM-plant Bt than the commercial Bt sprays.

The report is a strong indication that New Zealand native insect species could be severely affected by transgenic Bt (Cry gene) crops as they carry out a much bigger pollination role than previously thought. (Cronshaw T, 2005).

It also shows Bt plants put could undermine other scientific work to develop natural bio-controls for problem insects.

"Any chronic, sublethal effects of this toxin in soil or plants on non-target predator species could severely damage the management methods of bio control where predator insects are used to manage prey pests," said Claire Bleakley of GE Free (NZ) in Food and Environment.

"Any threat to this farming method is of concern as the prey /host relationship is a major tool in IPM (integrated pest management) farming methods, which is part of our international position as a clean-and green producer."

In New Zealand a comprehensive range of fungi, protozoa, nematodes, bacteria and predator insects moths, wasps have become available to farmers for pest control. Many of these bio control agents live in the soil and are an important part of ecosystems. This review has collated the research showing that these organisms been shown to be highly susceptible to Bt toxins.

"In light of these adverse effects authorities must require that long term indoor safety and diagnostic tools are developed for testing of these plants. The research when completed must be peer reviewed and published before any plant is allowed to grow outdoors," says Claire Bleakley. "ERMA must not approve the field testing of Bt brassica (cabbage, cauliflower, broccoli and forage kale)".


Claire Bleakley (06) 3089842 027 348 6731


Hillbeck A. and Schmidt J., (2006) Another View on Bt Proteins - How Specific are they and What Else Might They Do? Biopestcide.In: 2 (1): 1-5.

Tim Cronshaw, Flies show pollen power. The Press, October 2005, http://gefreesonoma.org/documents/Fliesshowpollenpower

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