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FOR IMMEDIATE RELEASE Thursday, 05 July 2001 PARASITE PUTS PUTTING GREEN PESTS IN THEIR PLACE On the golf course, Dr. Robert Wick takes his best shot with a tiny parasite. Wick studies nematodes -- little round worms, the diameter of a hair and 1/32 of an inch long, that can take a real toll on the turf. "Nematodes are the most abundant animal in soil," notes Wick, "and they are more abundant on putting greens than in any other agricultural setting, up to 10,000 of them in a hand full of soil." Most nematodes feed on soil microbes, like algae, fungi and bacteria, but some are serious plant pests, such as the "root knot nematode" on putting greens. These nematodes insert their hollow needle-like mouthparts into root cells and feed inside individual cells. With enough feeding, the root loses its ability to transport water and nutrients, and the grass dies. Golf course managers can control nematodes with pesticides (nematicides) or by fumigation, but these treatments are hazardous, expensive and the results are short-lived. Wick has searched for alternatives to pesticide control of nematodes for over 10 years. He has tried plant extracts, high-pressure water injection, biological controls such as fungi and other nematodes, and "just about every commercial product on the shelves." Nothing has appeared effective. A call from a Rochester golf course brought a new idea. On this 36-hole golf course, 18 of the putting greens had been fumigated a few years back and 18 had not. The course manager reported that the fumigated greens looked great for a while, but six years later, the fumigated greens had damaging nematode problems and the non-fumigated greens were fine. Wick took samples and found that the nematodes on non-fumigated greens were 90% infected with a bacterium called "Pasteuria." This is no ordinary bacterium as Wick explains, "each bacterium is about 5 times larger than usual bacteria. When a single bacterium lands on a nematode, it sends an infection tube into the body of the worm and soon fills the body cavity with bacteria. These sterilize the nematode." In fumigated greens, however, there was very little bacterial infection "It suggested to me that if you let things alone long enough, the bacterium may suppress the nematodes," says Wick. "We are looking to see whether or not pesticides are inhibiting the natural suppression of nematodes. When you kill the predators, you inherit their work." Pesticides have often been implicated in killing the organisms that naturally control pests. A method of pest control called integrated pest management, or IPM, was started in the early 1960’s when scientists noted that in some fields, the use of pesticides killed natural predators, requiring farmers to use more and more pesticides. IPM includes a wide variety of tools, including growing techniques (pest resistant varieties and crop rotation for example), biological control (like Pasteuria) as well as the use of pesticides. The idea of IPM is to use the appropriate pest control tools without killing off the natural enemies. IPM includes a wide variety of tools, including growing techniques (pest resistant varieties and crop rotation for example), biological control (like Pasteuria) as well as the use of pesticides.
For further information: Dr. Robert Wick 413 545-1045 ARCHIVE: |
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