JACKSON, Miss. — The Mississippi Department of Agriculture and Commerce announced March 3 that it is temporarily lifting its restrictions for aerial applications of the burndown herbicide 2,4–D.

According to State Agricultural Commissioner Lester Spell, his department filed an emergency rule to suspend its wind speed restriction to allow farmers greater flexibility in getting their applications completed by March 31. In lieu of the 5-miles-an-hour wind speed restrictions, the emergency rule states that aerial applicators are to simply follow the product's label directions with respect to wind speed, velocity and direction.

The change will now allow hormone-type herbicide treatments to be applied by air when wind speeds are greater than 5 miles per hour, but less than 10 miles per hour.

"Continuous rain for the past month has prevented many aerial applicators from being able to operate, and hormone-type herbicide treatments of fields have had to be delayed because of the inability to fly. It is our goal to help provide our farmers with all the tools necessary to produce a crop in the most efficient and timely manner," says Spell.

Loosening the state's wind speed restrictions for 2,4–D applications does not, however, change the state's March 31 application cutoff date.

Applications of hormone-type herbicides, including 2,4–D, cannot be made from March 31 until Oct. 1 of each year using fixed-wing aircraft. This cut-off date does not apply to hormone-type herbicide applications made with the use of helicopters, the state agency says.

Hormone-type herbicides are chemical substances designed to produce physiological changes in plant tissue without producing a burning effect. They are readily absorbed by foliage and usually move (translocate) through the plant down to the root system. Examples of these herbicides include 2,4–D and dicamba.

The temporary regulation change for 2,4–D applications does not affect the state's ban against the aerial application of other preplant burndown herbicides such as glyphosate.

According to the Mississippi Department of Agriculture's Bureau of Plant Industry, burndown herbicides containing the active ingredient glyphosate, sulfosate and/or paraquat may not be applied by air without a permit beginning March 15 in some Delta counties.

Again this year, aerial applications of the commonly used burndown materials are restricted beginning March 15 for the Delta region south of Highway 8, and March 25 for the area north of Highway 8. Applications in both regions are restricted until April 30.

Affected by the March 15 initiation date are those areas south of Highway 8 in the counties of Bolivar, Sunflower, Leflore, and Grenada, plus the entire counties of Carroll, Holmes, Humphreys, Washington, Sharkey, Issaquena, Yazoo and Warren.

Aerial burndown applications north of Highway 8 in the counties of Bolivar, Sunflower, Leflore and Grenada, plus the entire counties of Tallahatchie, Tate, Quitman, Coahoma, Tunica, Panola and DeSoto, are restricted beginning March 25.

The 2003 burndown regulations maintain a provision for emergency exemptions granted by authorized Bureau of Plant Industry employees within the ban period. The state agency says this was done to provide applicators, producers and the general public considerable application flexibility while maintaining the regulatory objective of protecting susceptible foliage.

Provided when adverse conditions make ground application "impractical or unreasonable," 72-hour emergency exception permits are made on a case-by-case basis based on, among other factors, adjacent crops and weather conditions. The permits may be renewed.

To apply for an emergency exemption permit, aerial applicators should contact he Bureau of Plant Industry, and provide them with the farmers name, the field name, what product will be put out, and when the application will be made.

According to the supplemental application label, "The Bureau of Plant Industry may at anytime, based on current planting and environmental conditions, modify the restrictions."

States have the authority to be more restrictive than product labels to prevent or minimize off-target drift to emerging row crop plants and other vegetation. However, state regulations cannot be less restrictive than what the product label allows, according to Spell.

For more information, contact the Mississippi Department of Agriculture and Commerce, Bureau of Plant Industry at 888-257-1285.

e-mail: dmuzzi@primediabusiness.com.