Biotech Breakthrough

first_imgPappu worked to find the secret of when the thrips can transmit TSWV. He’s usingnew biotech methods to detect specific proteins that appear only when the insect cantransmit the virus. And they’re doing it quickly. “The presence of the viral protein is a good indication that the insect was capable oftransmitting the virus,” Pappu said. Pappu points out, too, that the 10 percent average is just that. “Some farmers lost only1 percent or 2 percent,” he said. “Others may have lost close to 50 percent.” The three main crops the virus affects are peanuts, tobacco and tomatoes. But manyothers are affected. In these three crops alone, Georgia farmers lost $63.8 million in1996. The virus affects the crops differently, but the results are the same: decreasedyields and crop loss. Viruses rely on carrier insects, he said. The TSWV relies on tiny insects called thripsto move from plant to plant and field to field. “Tomato spotted wilt virus is the No. 1 problem in the state’s crops,” said Hanu R.Pappu, a plant pathologist at the Coastal Plain Experiment Station. “Last year alone, itcaused an average 10 percent loss in many affected crops.” Past efforts to control tomato spotted wilt by controlling the insects didn’t work. “Wejust didn’t know at the time that only certain populations were transmitting,” he said. The first problem farmers have with the virus is knowing when it’s in their fields.Since it’s a virus, Pappu said, there’s no cure. The method he uses is called TAS ELISA; Triple Antibody Sandwich, Enzyme-LinkedImmunoSorbent Assay. It uses virus-specific antibodies that reveal if viral proteins arein the insect. In past years, Georgia farmers had a tough row to hoe in many crops in fighting thedeadly tomato spotted wilt virus. Now, new technology can give them an edge inmanaging the virus. But while about a dozen species of thrips live in Georgia, only two can transmitTSWV. “And those two species can transmit the virus only when the insect wasinfected as a juvenile,” Pappu said. For the first time, Georgia scientists can learn in just one day if insects in the field areactually transmitting the virus. Pappu is working with another plant pathologist and an entomologist at the experimentstation to learn the secrets of the virus that causes tomato spotted wilt. Once they learnits secrets, they can use them to fight against the tiny but destructive organism. Before, scientists needed six to eight weeks to find out if a thrips population wastransmitting the virus. “Now this technology can tell us in one to two days,” he said. “So prevention is extremely important,” he said. “There is no control, so we’re tryingto get it to a point where we can manage the disease through other means.” Pappu’s goal is to forecast when a transmitting population is moving into a field.Armed with that knowledge, farmers can apply pesticides to kill the insects before theycan transmit the virus into the plants. “This information will allow them (farmers) to be more precise in applying chemicals,”Pappu said. “To be effective with our applications, we needed an efficient, quick wayto know if the population was transmitting.” Now they have it.last_img

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