Scientists: Bt toxins can be used for pest control

MANILA, Philippines - A group of German scientists have found that toxins produced by Bacillus thuringiensis (Bt) can be used for pest control, a Manila-based online science news agency said.

Bt is the bacterium used by biotechnologists to develop pest-resistant yellow corn and some varieties or rice, eggplants and a host of other genetically modified (GM) or transgenic crops.

It produces a toxin that affects only certain insects but not other organisms.

Researchers at the Max Planck Institute in Jena, Germany said Bt toxins have been used as pesticides since 1938 to minimize attacks by herbivorous insects, 28 years after Bt itself was isolated from soil and found to be a beneficial bacterium, the Biolife News Service said.

Since 1996, Bt-producing transgenic crops have been grown and succeeded in controlling pests that ranged from the European corn borer, the tobacco budworm to the Western corn rootworm and cotton bollworm, it said.

“These toxins, named Cry1AbMod and Cry1AcMod, have been combating five resistant insect species like the diamondback moth, cotton bollworm and the European corn borer,” the Biolife News Service said.

It added that Cry1AbMod and Cry1AcMod could be used separately or in combination with other Bt toxins to strengthen the protection of crops.

The news agency said the toxins were specifically effective against a super-resistant strain of tobacco budworm that contains both the cadherin mutation and another mutation affecting an ABC transporter that was discovered by Max Planck scientists last year.

Of particular interest to the scientists was the effect of Cry1AbMod and Cry1AcMod on a Bt-resistant corn borer and a resistant diamondback moth strain and the impact was 350 times stronger than that of natural toxins, it said.

However, the new toxins only had a weak effect on strains whose Bt resistance was due to a mutated cadherin.

In the Philippines, researches on transgenic plants are regulated by the National Committee on Biosafety of the Philippines whose strict guidelines ensure the safety of the public and the environment before granting permission for researches in this field.

Reports said the Philippines has one of the most stringent biosafety guidelines in the world.

In May 2002, the Department of Agriculture issued Administrative Order No. 8, which sets the guidelines for the importation and commercialization of GMOs. The Bureau of Plant Industry accepts, processes and approves applications from proponents and importers.