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Tony Shelton


Expert Bio

In 1979, Anthony Shelton received his Ph.D. from University of California, Riverside and joined Cornell’s faculty the same year as a professor of entomology and College of Agriculture and Life Sciences International Professor. He leads a research and extension program that develops integrated pest management strategies for vegetables and other crops, and it focuses on helping growers implement sound IPM strategies and educating the public about agricultural issues, including biological control and biotechnology. In 2010, Shelton was elected a Fellow of the Entomological Society of America. He is a three year participant of the Global Biosafety Management Program in India, and he participated on the National Academy of Sciences, Board on Ag Review for three years.

Studies, Articles and Answers

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Q: What influence do the Bt genes and the substances that they generate have on other insects and microorganisms in the soil? There's a great deal of controversy on the subject and I would love to learn the truth.

Answered By Tony Shelton - Dec 24, 2013

A: Strains of Bacillus thuringiensis (Bt) are commonly found in soil. The genes within Bt produce many different proteins in the soil and there are thousands of different arthropods, nematodes and microorganisms in the soil. There are books written about their potential or actual interactions, however, it should be remembered that these interactions are a natural part of the soil ecosystem.   Briefly, insecticidally active 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&nb [...]

GMOs & Farmers How GMOs Are Made Crop protectants


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

Answered By Tony Shelton - Dec 24, 2013

A: 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: In plants that have been genetically modified to pro [...]

GMO Basics GMOs & Farmers Crop protectants


Q: Can GMO help in the fight against invasive species

Answered By Tony Shelton - Aug 25, 2015

A: This is a good and complex question! Just so we are on the same page, first let’s define what an invasive species is. A scientific panel has defined it as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” An invasive species can be an arthropod, weed, virus or another organism. Your question really focuses on whether a GMO can be used to combat an invasive pest species. Let’s take insects and a virus as examples.   Many pests of our food [...]

GMOs Globally Health & Safety How GMOs Are Made


Q: Can you explain the biology behind Bt Corn and its effect or lack of on humans? How exactly is the Bt specified to work only on insects and it does not effect humans? Im wondering about enzymes, proteins, recognition, etc. Im looking for a scientific answ

Answered By Tony Shelton - Jan 12, 2016

A: Bacillus thuringiensis (Bt): human and environmental safety Anthony M. Shelton, Professor of Entomology, Cornell University   What is Bt? Bt is short for Bacillus thuringiensis, a bacterium in the genus Bacillus. Members of the genus Bacillus are generally considered soil bacteria, and Bt is common in terrestrial habitats including soil, living and dead insects, insect feces, granaries, and on the surfaces of plants. Bt occurs in nature predominantly as spores that can disseminate widely throughout the environment. The diversity within B. thuringiensis&n [...]

GMO Basics Health & Safety Crop protectants