QHow long does Bt remain on or in plants that are sprayed with Bt?

How long does Bt remain on or in plants that are sprayed with Bt?

AExpert Answer

Bt proteins are degraded within just a few hours in sunlight. Because degradation occurs so rapidly, the spores and crystals are usually applied in some type of formulation to decrease the degradation rate. But even formulated Bt products lose their insecticidal activity within about 4 days. Degradation time may be even shorter than 4 days, depending on the effects of microbial degradation, dew, and washoff due to rainfall events. (for more background on BT see:http://pmep.cce.cornell.edu/profiles/extoxnet/24d-captan/bt-ext.html)

In plants that have been genetically modified to produce Bt insecticidal proteins, there will be a fairly constant  supply of the Bt proteins in the leaf tissues while the plant is alive. These Bt proteins generally interact only with insects that have a specific pH in their digestive system and a binding site in their gut that can attach to a specific site on the Bt protein. The requirement for a specific pH and a unique binding site means that a Bt protein can have an effect on target pests or closely related insects, but at the same time have no effect on other insects or organisms. After the plant dies at the end of the season, the Bt proteins a rapidly degraded in the soil along with all of the other proteins contained within the plant materials, which is fitting considering Bt is naturally found in soil.

Posted on January 31, 2018
Thank you for your question. There are various aspects of your question. I assume your question refers to the use of Agrobacterium rhizogenes by scientists to intentionally transfer genes from the bacterium to plants. Infection and DNA transfer from this bacterium occurs in nature all the time to cause disease. Such transformed plants are not classified as GMOs since transfer occurred naturally. If this is done by scientists then it would be classified as a GMO. Rules and... Read More
Answer:
Posted on March 1, 2018
I’m a Monsanto scientist who has more than 20 years of experience with genetic modification of plants. I will try to answer your question, even though I don’t ever do experiments on animals, certainly not on humans, of course! Can humans be genetically modified…but a much bigger question is should humans be genetically modified? There are two ways to think about genetic modification of humans (or any animal). One way is modification of somatic cells, and the other is the... Read More
Answer:
Posted on May 10, 2017
The simple answer is that 20+ years of composition assessments of GMO crops have demonstrated that crop composition is not appreciably affected by the GM process (1). In addition, data collected through that time have indicated that general factors such as the growth environment can contribute to notable variation in component levels (2). Plant agglutinins (or lectins) and amylase inhibitors are examples of anti-nutritional compounds that may be present in crops. The relevance of such a... Read More

Explore More Topics