UA News

Bruce Tabashnik is part of a documentary's exploration of the role plants have played throughout human history.

A two-hour Public Television documentary this month will delve into the role of plants throughout human history. Michael Pollan will host the film, based on his 2001 book, "The Botany of Desire." Academy Award winner Francis McDormand is the narrator. The film also includes an interview with Bruce Tabashnik, a professor and head of the entomology department at the University of Arizona.

Pollan's film explores the human-plant relationship through four specific plants that reflect human desire for sweetness (apples), beauty (tulips), intoxication (marijuana) and control (potatoes).

The New Leaf potato was at the center of controversy years ago. That's because it was genetically modified to produce an insect-killing protein from the bacterium Bacillus thuringiensis, or Bt. The Bt protein in New Leaf potatoes kills larvae of the Colorado potato beetle. Food processors declined to buy New Leaf potatoes citing potential public backlash, and so the potato is no longer grown.

Tabashnik is an authority on the role of Bt in controlling the pink bollworm, a major cotton pest. He said that while he is not an expert on either potatoes or the Colorado potato beetle, it nevertheless is important that people understand the larger systems behind crop production and their impacts.

"They should think about how and what they eat and how that affects the environment, agriculture and the future," he said.

"We're voting with our dollars every day. Most people in the U.S. don't think too much about it, but there is some sense that if they buy genetically engineered products, it might be dangerous or harmful. But in fact, clothes made from Bt cotton are part of a more environmentally sustainable process because there are less insecticides sprayed on cotton fields. And that's a good thing," he said.

Tabashnik said the University of Arizona over the last decade has become a world center in studying the extent to which insects adapt to genetically engineered crops, including overcoming the Bt toxin. 

"Insects are champions of adaptation and have a long history of adapting to virtually every method to control them, including every kind of insecticide. This is just another case in that history of insects evolving resistance," he said.

Tabashnik said that some other pests have adapted, but the pink bollworm, a caterpillar that feeds on cotton, is probably the best documented example of an insect that has not become Bt resistant.

Bt also is at the heart of a new assault in the battle against pink bollworms. Previously, farmers who planted Bt cotton were required to set aside a small area for non-Bt varieties to allow non-resistant pink bollworms to survive.

The new strategy involves spreading millions of sterilized moths during the growing season over cotton fields throughout Arizona, the Southwest and northern Mexico.

Should a Bt-resistant bollworm develop into an adult, Tabashnik said the likelihood it could find a fertile mate would be virtually zero.

"They'll mate with a sterile partner and produce no offspring. It's a strategy that's working," he said.

Tabashnik said he and other officials with the Arizona Pink Bollworm Technical Advisory Committee will review the progress of the program on Tuesday in Phoenix.

"The Botany of Desire" airs on Public Television stations around the U.S. this Wednesday. Arizona Public Media's Channel 6 will show it starting at 8 p.m.