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Crop Pest Management News

10-30-98 CU research discovers natural control for nematodes

9-8-00 Pest battle goes high tech

DATE: 10-30-98

CONTACT:  Bruce Fortnum, (843) 662-3526 bfrtnm@clemson.edu

WRITER: Debbie Dalhouse, (864) 656-0937 ddalhou@clemson.edu

CLEMSON SCIENTIST DISCOVERS NATURAL CONTROL FOR PLANT PARASITE

FLORENCE, SC - A Clemson University scientist has discovered how to use light to manage a parasite that reduces crop yields around the world. Bruce A. Fortnum, a Clemson plant pathologist, found that altering the light by surrounding a plant with red plastic soil mulch reduces crop losses caused by the root-knot nematode.

The parasite affects major food and fiber crops, such as tomato, soybean, peanut, corn, cotton and tobacco, by diverting nutrients from the plant's shoot to the root system. This means that crops are sacrificed as the plant's energy goes to feeding the parasite attached to its root system.

Fortnum has found a way to overcome this challenge by using the plant's natural growth regulatory system, called phytochrome.

"Plants respond to the energy in far-red light with an increase in shoot growth," Fortnum said. "Humans can't see far-red light, but it is a component in sunlight. More far-red light reaches the plant at the end of the day as the sun's rays pass through the atmosphere.

"The far-red light reflected from red plastic mulch sends a growth signal to the plant throughout the entire day. As a result, the plant sends nutrients to the shoots in spite of the nematode's presence. This reduces the nematode's reproduction rate and allows the plant to produce its crop," he said.

Fortnum is the first scientist to report that the light environment of the shoots affects root-knot nematode reproduction in the roots. His research has provided the foundation for a science-based nematode management system that is environmentally sensitive and could contribute to other nematode management systems.

Fortnum's findings build on a discovery in the early 1980s by Clemson horticulturist Dennis R. Decoteau and U.S.D.A. scientist Mike Kasperbauer, who found that red plastic mulch dramatically improved the size and taste of tomatoes. He collaborated with them and with and other scientists at Clemson's main campus and its research centers across South Carolina. Their studies suggest that combining other environmentally friendly systems, such as crop rotation and variety selection, with the use of red reflective films can significantly reduce the losses caused by root-knot nematodes.

"The creative partnerships formed by Clemson researchers such as Bruce Fortnum lead to major discoveries that are contributing to improved crop production for South Carolina that will make a major impact around the world," said James R. Fischer, director of the South Carolina Agriculture and Forestry Research System based at Clemson. 

Fortnum's research has received national attention from professional publications such as Science News, Agricultural Research and HortScience Journal. He has also presented his findings at scientific conferences in Europe, Asia, South America and Africa. Recently, Fortnum received the Philip Morris USA award for distinguished achievement in tobacco science because of his significant contributions to the understanding of the biology, ecology and control of the root-knot nematode parasite of tobacco.        

Further research is needed to understand the genetic make-up of nematodes and to develop a field-practical system to analyze the soil and recommend solutions for specific growing conditions. The genetic analysis will be conducted in Clemson's Genomics Institute, a national resource center capable of mapping the entire genetic blueprint of major food and fiber plants and the pests that reduce crop yields. 

Fortnum earned his bachelor's degree in biology from LaSalle College, his master's degree in plant pathology from the University of Delaware and his doctoral degree in plant pathology from Clemson University. He joined the Clemson faculty in 1979 and is currently stationed at the university's Pee Dee Research and Education Center in Florence, S.C.

END  

DATE: 9-8-00

CONTACT: Ahmad Khalilian, (803) 284-3343 akhlln@clemson.edu

John Mueller, (803) 284-3343 jmllr@clemson.edu

WRITER: Tom Lollis, (803) 284-3343 tlollis@clemson.edu

Debbie Dalhouse, (864) 656-0937 ddalhou@clemson.edu

PEST BATTLE GOES HIGH TECH

BLACKVILLE - Using the Global Positioning Satellite (GPS) system and an electrical conductivity meter, Clemson University scientists are going high tech in the war against nematodes - microscopic worms that cause millions of dollars in crop losses each year.

Ahmad Khalilian, a Clemson agricultural engineer, is leading the research team that is tracking nematodes in three states: South Carolina, Arkansas and Missouri. Nematodes prefer sandy soil, which has a lower electrical conductivity level than does heavier clay soil. So the scientists are using a soil conductivity meter to identify the sandy areas, then using the satellite system and a computer on a truck or tractor to record the precise locations of nematode infestations. With this information, chemical controls called nematicides can be applied only to the infested areas instead of to the entire field.

"This adds a new dimension to precision agriculture," Khalilian said. "Growers have been using the GPS system to track yields and determine application rates for fertilizers, pesticides and herbicides. With this technology, we could develop equipment to apply nematicide in the precise amounts and locations where it's needed." This precision approach would reduce the amount of chemicals used, saving growers money and protecting the environment.

The soil conductivity meter, developed by Veris Technologies, looks like a small disc harrow and is towed behind a tractor or truck at speeds of up to 12 mph. It sends electrical charges through the soil and helps determine soil type based on how well the charge is conducted. With it, researchers can map a 20-acre field in an hour or less, instead of the several days that are needed for manual sampling and standard laboratory analysis.

Cotton is the crop being studied in this project, but nematodes attack a wide range of crops from soybeans to tomatoes. The three-state project includes a number of nematode types, as well as soils and climates, to represents the conditions faced by growers in many temperate regions around the world.

The Clemson research team is based at the university's Edisto Research and Education Center in Blackville with other scientists participating from the main campus. It includes plant pathologist John Mueller and agricultural engineers Young Han and Fran Wolak, in addition to Khalilian. Joining them are plant pathologists Terry Kirkpatrick at the University of Arkansas and Allen Wrather at the University of Missouri, who are leading the research teams in those states.

This research is funded by a $772,470 grant from the United States Department of Agriculture. The current study grew out of earlier research on precision agriculture that was funded by the South Carolina General Assembly in 1997, called the 2x4 initiative. The original project has attracted more than $150,000 in grants and equipment from outside the university since January 1999.

"This is an example of how a creative group of faculty can work together to leverage state resources to bring in external sponsors for program work," said John Kelly, vice president for public service and agriculture at Clemson University. "That allows us to accomplish much more than we could with state resources alone."

The study is being conducted through Agriculture and Forestry Research at Clemson. Findings will be shared with growers through the Cooperative Extension Service and with Clemson students through agricultural engineering classes.

END