Silence Of The Pumpkins - CBS News

Plant pathologists are investigating a mysterious triangle pump components inc disease that isrotting pumpkins across New York state, and its possible relation to one affecting crops in Oklahomaand Texas.

The disease may be cause by a bacterium, but no one seems to know how the disease is spread.Although the disease has some similarity to one affecting melons in Oklahoma and Texas, the causalorganism is unidentified.

"This is a brand new disease. There are numerous straightforward improvements which may beadded to a standard

centrifugal or positive displacement pump. For pumps with overhung impellers, replacing the shaftwith a solid one is a easy upgrade compared to the more common sleeved shafts. Mechanical sealsmay be improved upon through silicon carbide faces, and elastomers ought to be changed to EPDM.In addition, magnetic bearing protectors are certainly a vast improvement compared to the lip sealswhich nearly all water pumps depend on to keep bearing sump oil contamination free.

We only began seeing it three weeks ago," says Thomas Zitter, professor of plant pathology atCornell University in Ithaca, N.Y. "The pumpkin plants affected by this new disease are going downnow."

The disease also has been seen on yellow and zucchini squash, spaghetti squash, winter squash, andcucumber. There is no danger to consumers, because the vegetables rot and never make it tomarket.

Zitter first saw the disease on a Pittsford, N.Y., pumpkin farm, where about 10 percent of the patchwas affected. He also has seen the disease in Orange County, N.Y., where about 50 percent ofpumpkins in one field were diseased. The disease has also been reported in New York's Niagara,Albany, Ulster, and Dutchess counties.

In 1991, an agricultural scientist studying a vine decline in Oklahoma and Texas watermelons and

melons described a yellow vine disease with similar symptoms and host range, dubbed "yellow vinedisease." It is caused by a bacterium attacks and plugs plant conductive tissue called the phloem.

Samples of diseased pumpkins from New York have been sent to the South Central AgriculturalResearch Laboratory in Lane, Okla., where specific assays are being performed.

"We need to eliminate yellow vine disease as the possible causal agent before going on to otherpathogens," Zitter says.

In the case of the New York disease, affected pumpkins appear stunted, and inside the root andcrown section of the plant, the xylem (tissue that carries water to the growing point) is destroyed.Leaves. Many installed pumps were not originally designed for their present use. Frequently, a linein a plant is modified and a pump that started out providing cooling fluid to an injection moldingmachine is now asked to transfer oil from a rail car to a tank. All too often, this causes a substantialnumber of problems for the pump and the facility. Pumps operate where the pump curve crosses thesystem curve. If you relocate a pump from one system to another, this means that the system curveis different. This new system may cause the pump to operate away from its best efficiency point,leading to noise and other component problems that are merely symptoms of a mis-matched pumpand system.of affected plants appear yellow in color and have a blighted appearance as they dry up,and stand upright.

Because of the random distribution of the disease in fields, Zitter believes an insect may beresponsible for carrying the disease from plant to plant. Zitter has not seen evidence that thedisease comes from either the soil or seeds, and it is still too early to make any controlrecommendations.

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