Archived Issues

Sucker control

Proper sucker control cuts down on extra work and improves yields.

Rocky Womack

A good sucker control management program can relieve the pressure of pulling overgrown suckers and allow plant growth to go into the leaves instead of the pesky suckers. Quality and yields are also improved.

“When plants are in full flower, research shows that yields are reduced by 1 percent per acre per day,” says Loren Fisher, assistant professor and tobacco Extension specialist with North Carolina State University (NCSU) in Raleigh, N.C.

He recommends topping in the early button stage and applying the necessary sucker controls with the proper amount of water as called for on the chemical label. However, some growers continue to ignore this advice and let blooms and suckers fill out, causing both to become tough and hard to break out. They risk letting high winds topple the plants from the extra weight of the blooms and suckers.

“Many growers wait to top plants, because they are difficult to top mechanically at the early button stage or because they may not have the labor to top in a timely manner,” Fisher says.

Topping early and applying sucker controls at the right time can stimulate early root development, according to the North Carolina State Cooperative Extension Flue-Cured Production Guide. Extension recommends applying a contact solution that can chemically top 5 to 10 percent of the small plants in a field. Early root development can lead to better fertilizer efficiency, drought tolerance and alkaloid production. In addition, insects are less attracted to the plant when large blooms and suckers are removed, especially aphids.

Extension advises avoiding excessive amounts of nitrogen, which can cause suckers to grow rapidly and can delay leaf maturity as well. Additionally, Extension recommends applying nitrogen at a rate of between 50 and 80 pounds per acre.

Timely control

Other growers stay on top of their sucker control management programs and revise when necessary. Ringgold, Va., flue-cured tobacco growers Jimmie and Tommy Collie use a fatty alcohol contact, usually Off-Shoot T, although there are many contact choices on the market. A contact kills by burning when the chemical touches small suckers, usually less than 1 inch. The chemical must touch all suckers to kill them. They follow the contact a few weeks later with the localized systemic Prime Plus, which also must touch suckers and wet them before it stops cell-division growth.

On a second pass of their fields, the Collies sometimes use a contact mixed with the localized systemic, then follow weeks later with the true systemic maleic hydrazide (MH). True systemics retard rather than kill sucker growth by inhibiting cell division.

Jimmie Collie stresses he never mixes the contact and localized systemic on a first pass of his fields, because the localized systemic can damage the smaller leaves in the top that have not matured yet. The localized systemic stops leaf growth.

“You want your crop up where it’s uniform,” Collie says. “You want to let the later plants get leaves made, unless you are very uniform and got the leaf size you want [already]. Prime Plus is like MH-30. It will put a halt to everything.”

Extension recommends waiting to apply a local systemic until upper leaves are near harvestable size.

The Collies top their crop with a mechanical topper rather than break out the blooms by hand, which requires more labor. They spray on the contacts and systemics with a tractor sprayer instead of using a jug or drop line filled with the product. Farmers who apply with a jug or drop line turn it over the plant and let the chemical run down the stalk while the contact touches each leaf axil where the sucker grows.

Of course, never say never. The Collies have used jugs when they needed to in controlling suckers. Usually, that occurs when a field of plants is irregular rather than uniform.

As most growers know, controlling suckers isn’t as easy as it sounds in every case. “Always, if you’ve had any kind of storm or wind damage where that plant has a crook, you’re in a world of hurt on a contact,” Collie says. He explains a contact will change direction once it hits the crook on the stalk. That could stop it from running down the stalk to touch all leaf axils. In most cases, the Collies spray a local systemic rather than a contact, and sometimes they do this sooner than normal to catch any sucker growth. When plants are bent from bad weather, they grab their jug filled with contact material and apply some at the top of the plant, then make another application in the middle of the plant below the crook, so the contact is sure to reach all leaf axils.

NCSU recommends applying fatty alcohol contacts at the proper strength until the crop evens out and the upper leaves reach a desirable size. “Many years, two contact applications will be adequate,” Fishers says. “However, with uneven tobacco or when tobacco is growing slowly, additional contact applications may be needed.”

He advises following contact applications with a tank mixture of MH or MH-containing products with flumetralin for flue-cured tobacco or flumetralin or butralin for burley tobacco. Fisher says for plants that are leaning, contacts, flumetralin and butralin “may miss leaf axils during stalk rundown, and since these products require contact with suckers for control, missed leaf axils will not be controlled until MH, which is a systemic, is applied.”

Topping early when about 50 percent of the tops reach the button stage and pulling any suckers that have grown more than 1 inch is good advice. A contact usually will not burn a sucker properly if it is too long.

When spraying a suckercide, Extension recommends using two TG-3 nozzles and one TG-5 nozzle at a tractor speed of 3 miles per hour and a pump pressure of 20 to 25 pounds per square inch. This allows for more accurate application and better sucker control. Removing any suckers missed by a suckercide is good advice to keep them from growing, which can cause the growth weight to go into the sucker instead of the plant, thus reducing yields.

Keeping an eye on the Weather Channel or local weather reports will help too. If heavy rains occur within a half hour to one hour after application, growers may want to consider holding off on spraying until the weather front passes.

Extension recommends not reapplying MH during dry periods to avoid a buildup of MH residues. Tobacco contract buyers have indicated that their domestic and foreign customers do not want high levels of MH in cured leaf and are strict about that issue. The unofficial tolerance level for MH residues continues to be 80 parts per million.

Another approach

Earl Brooks Jr. of Piedmont Burley LLC is a flue-cured and burley grower in Roxboro, N.C., who hand-tops his tobacco and sprays on sucker controls. He first sprays on two contact applications, then a few weeks later applies a Flupro and MH combination, which normally works well. “We had some trouble last year,” he says. “It did not receive well on the plant.”

Dry weather in August and September prevented the sucker controls from acting properly as the plants stood in the ground without growing. Once rains did come, the strength of the MH had faded out, Brooks says, and the tobacco turned green and started to grow. Because the MH had weakened during four weeks of drought, he ended up with more late-season suckers than he intended.

As a young boy, Brooks remembers having to pull fields and fields of suckers, something he doesn’t relish doing. “I remember laying around in the row thinking, [there’s] got to be more to life than [pulling] suckers.” While pulling them, he recalls looking up from the plant and wondering, “How many are in these fields?”

Today, Brooks rarely worries about pulling so many suckers as long as he effectively manages his sucker control program and makes timely applications of contacts and systemics.

For more information on sucker control, growers can refer to the 2007 NCSU flue-cured or burley production guides available online by selecting Production Guides at http://ipm.ncsu.edu/, or growers can view production guides from other state universities such as Georgia, www.georgiatobacco.com; South Caro-
lina, www.clemson.edu/peedeerec/
tobacco/; Tennessee, http://tobaccoinfo.
utk.edu; Kentucky, www.uky.edu/ag/
tobacco/; and Virginia, www.ext.vt.edu.