Farm Facts for Fairfield County

for March 21, 2003 ; also seen on Fridays in the Lancaster Eagle Gazette

As the West Nile Virus (WNV) threat buzzes again over Ohio with the first signs of warmer weather and the upcoming mosquito season, Ohio State University Extension specialists are gearing up to educate the public about this viral disease and help protect people and livestock from its potentially fatal effects.

William Saville, Extension veterinarian and epidemiologist, and Joanne Kick-Raack, coordinator of Extension's Pesticide Education Program, have recently received funding from the Ohio Department of Health (ODA) to implement educational programs throughout the state.  Saville and Kick-Raack are active members of the Ohio West Nile Virus Work Group --an alliance of state agencies formed in 2000 to respond to the rapid spread of WNV across the country.

"This year we are doing a little more than we have done in the past to educate the public about West Nile Virus," said Saville, who chairs the Work Group's education and communication subcommittee.  "Despite our educational efforts, we think many people still don't recognize the importance of protecting themselves."

Saville said 2002 was a wake-up call for all Ohioans, as the virus spread to the state's 88 counties, infecting 444 people (31 of which died) and more than 600 horses (a third of which either died or were euthanized).

WNV was first reported in the United States in 1999. Previously see only in Africa, Asia and southern Europe, West Nile's most serious manifestation is fatal encephalitis (inflammation of the brain and the spinal chord) in humans and horses. It also causes mortality in certain domestic and wild birds, especially crows and blue jays.
The disease is spread by the bite of mosquitoes that became exposed to the virus after feeding on infected birds.  Most of the people who contract it suffer nothing more than headaches and flu-like symptoms, such as fever as muscle aches. High fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions and paralysis mark more severe infection. At its worst, the virus causes encephalitis --especially among the elderly, chronically ill and others with weak immune systems.

West Nile Virus educational programs developed by OSU Extension this year include conferences and lectures, special campaigns for Spanish-speaking populations, the Amish and the elderly, and mosquito control workshops.

Saville and Kick-Raack are coordinating the preparation of Spanish-language printed materials and radio public service announcements to target Ohio's growing Hispanic population. A similar campaign is also being prepared for the Amish.

"We suspect that our previous messages have been missed by Hispanics and Amish because of the language barrier and because we didn't target publications they read," Saville explained.  "This time we will deliver the message via Spanish-language media and publications the Amish usually read. We will also reach these audiences through Extension personnel who work with them."

An additional campaign will focus on educating the elderly about West Nile Virus. The reason is obvious --of the 31 WNV victims in Ohio, 22 were over 70 years old and only three were younger than 60.

In the meantime, Kick-Raack is organizing several pesticide training workshops aimed at maximizing the effect of fumigation efforts as well as reducing health and environmental risks. One of the workshops, April 11 at Ohio State in Columbus, will provide officials and administrators from communities across the state with the tools necessary to set up effective mosquito control programs.  Experts will talk about the equipment and products needed for such programs and proper timing of applications.

The April meeting will be followed by four regional vector control workshops, which will be held during June in the vicinity of Cincinnati, Cleveland, Columbus and Toledo. The workshops are intended for both public mosquito control crews and commercial applicators.

"They can bring their trucks and spray equipment to these workshops," Kick-Raack said. "We will calibrate their equipment by computer, analyzing and setting proper droplet size so pesticides are properly applied."

Applicators will learn more about the status of WNV in Ohio and topics such as mosquito biology and surveillance. They will also receive safety information and training to help them become licensed.

"We want well-trained applicators and properly operating equipment when we use pesticides so that we can minimize any risks or concerns," Kick-Raack pointed out. "We want to protect people and the environment."

Horse owners are being advised to vaccinate their animals now to protect them against the virus. Saville said horses should be vaccinated twice, three to six weeks apart, while horses vaccinated last year need a yearly booster. Horse owners should also eliminate mosquito-breeding areas around the farm and watch for common symptoms of infection --such as lack of coordination, loss of appetite, weakness or paralysis of the hind limbs, fever, twitching, aimless wondering and convulsions.

Since no vaccine is available to protect humans from WNV, the emphasis right now is on protection and prevention. To reduce the chance of infection, ODA is asking citizens to:

* Make sure that doors and windows have tight-fitting screens.

* Remove all discarded tires from their properties and dispose of cans, plastic containers, ceramic pots and similar water-holding containers.

* Make sure roof gutters drain properly and keep them clean.

* Clean and chlorinate swimming pools, outdoor saunas and hot tubs.

* Drain water from pool covers.

* Change the water in birdbaths at least once a week.

* Turn over plastic wading pools, wheelbarrows, etc. when not in use.

* Clean ditches of obstructions so they can drain properly.

* Eliminate any standing water that collects in their properties.

* Check trees for cavities that hold water and fill them with soil, gravel or sand.

* Remind or help neighbors to eliminate breeding sites on their properties.

* Avoid being outside between dusk and dawn, when mosquitoes are likely to be biting.

* When outdoors, wear light-colored clothing, long-sleeved shirts or jackets, long slacks, socks and shoes.

* Use mosquito repellent containing DEET according to label directions (no more than 30 percent DEET for adults and 10 percent or less for children).

* Use mosquito netting when sleeping outdoors or in an unscreened area.

Weed Control Consequences Based Upon Prior Years' Practices - Stachler and Loux, OSU Extension Specialists

Weed populations change over time, and the production practices implemented by producers have a major influence in determining the nature of these changes.  In effect, the weed control and crop production practices of prior years have caused some of our current weed problems. Below are some examples of the weed population shifts or weed control problems that have occurred over the past 55 years due to management practices:

- Annual grasses became a problem in corn after the introduction of 2,4-D in 1947, because of the heavy reliance upon 2,4-D to control broadleaf weeds and the subsequent reduction in row cultivation;

- Fall panicum became a new weed problem in corn after the introduction of atrazine, because of the heavy reliance upon atrazine, which did not control fall panicum, continuous corn, and a reduction in row cultivation;

- Atrazine-resistant weeds began to occur in 1968, 11 years after the introduction of atrazine, because of the continued heavy reliance upon atrazine and continuous corn;

- Perennial weeds became more of a problem in corn and soybean fields after the introduction of no-tillage practices. By the 1990's, trees became a component of the weed population in long-term no-tillage fields;

- ALS-resistant weeds began to occur in Ohio in the mid-1990's, due to the heavy reliance upon Pursuit, Preview/Canopy, and other ALS-inhibiting herbicides and continuous soybeans;

- Annual grasses become a problem in no-tillage and reduced-tillage corn in the 1990's due to heavy reliance upon Extrazine, surface-germinating grasses that were not adequately controlled by chloroacetamide herbicides, the reduction of atrazine rates, and the elimination of row cultivation;

- Winter annual weeds increased during the late-1990's due to warmer winters, the practice of delaying burndown herbicide applications until planting (that allowed winter annual weeds to set seed), increased use of postemergence herbicides, reduced usage of preemergence herbicides, earlier harvesting (that allowed more time for winter annual weeds to establish), and increased no-tillage acreage;

- The increase in dandelion populations currently being experienced is due to the reliance upon only glyphosate in the burndown and in-crop applications in Roundup Ready soybeans, a decrease in the use of residual herbicides in soybeans and to some degree corn, the large number of no-tillage acreage, continuous soybeans, and the failure to use 2,4-D in burndown treatments;

- Glyphosate-resistant marestail is now present in Ohio due mostly to continuous no-tillage soybeans and the usage of glyphosate only for burndown and in-crop applications in Roundup Ready soybeans since 1997;

- One positive change has been the near extinction of jimsonweed.  This has occurred due to early planting, no-tillage, and use of ALS-inhibiting herbicides.

These examples illustrate the consequences or weed population shifts that can and do occur based upon the usage of a limited number of management practices. This is especially true when herbicides are relied upon as the main weed control tool.  Diversity in the sites of actions of herbicides is important to minimizing the number of herbicide resistant species. To achieve this diversity, preemergence herbicides should be used more often in soybean production, especially no-tillage soybeans.

Despite the many negative examples cited above, there are currently more methods and tools available to control weeds than at any time in the history of weed control!

For a listing of upcoming programs, meetings and events, visit the AG CALENDAR

Previous Issues of Farm Facts

updated on March 19, 2003 by Stan Smith

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
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