Sucker control and early topping lead the flue-cured tobacco farmer to high yields and quality. “Using the proper rates and timely applications of sucker control materials let the grower top early,” says Dewitt Gooden, Clemson University Extension tobacco specialist. “Research has shown that early topping and season-long sucker control mean higher yields and more value-per-acre at harvest.”
Sucker control may be necessary for 10 to 12 weeks of the growing season. Therefore, a combination of materials will likely be necessary for effective control, Gooden says.
Start early with a combo
It might be helpful to think of sucker control in terms of a combo meal. Contacts, local systemics such as Prime + and MH are necessary to complete the job, Gooden says.
It's best to get an early start on sucker control. That means a fatty alcohol contact material when approximately 50 percent of the plant is in the button stage. Delay beyond the 50-percent stage and the suckers will become too large to control with contacts. That will require extra hand labor.
“Farmers really need to pay attention to the concentration of the contact solution,” Gooden says.
Normally the first application is a four percent solution of two gallons of C8-C10 fatty alcohol mixed with 48 gallons of water. The second application, three-to-five days after the first, should be a five percent solution of 2.5 gallons of contact, mixed with 47.5 gallons of water
“Many growers use contact solutions that are too weak,” Gooden says.
“If five percent to 10 percent of the late plants in the field are not chemically topped, the concentration is probably too weak.” C10 fatty alcohol, which is hotter than C8-C10 fatty alcohols, is used at lower concentrations.
Proper nozzle selection, placement and pressure insure enough of the material, whether contact, local systemics or combinations, gets to the suckers.
The standard is a three-nozzle arrangement of two TG-3s on either side of the row and a TG-5 in the center with the pressure set at 20 psi. Gooden reports, however, that he's had success with larger nozzles — TG-6s on either side and TG-8 in the center — at speeds up to 4.6 mph.
MH remains one of the keys to sucker control when used in conjunction with contacts and local systemics, Gooden says.
Barring significant rainfall, he advises only one application of MH per season, applied to the upper third of the plant. “The key with applying MH is to use enough water,” Gooden says. “Fifty gallons is better than 25 gallons.”
Farmers have reduced MH levels across the flue-cured belt through wise use, Gooden says. Beltwide, MH residues have decreased to 80 parts per million last season from a high of 147 ppm in 1990.
The addition of Prime + to the sucker-control arsenal effectively gave farmers “a good way to insure season-long sucker control.”
Prime + is a local systemic and must run down the stalk to the leaf axil to be effective. Prime + can either be used separately or as a second or third contact, mixed and applied with MH or used three to four weeks after the regular MH application, Gooden says. Prime + is used at a rate of two quarts per acre.
About half of the growers in South Carolina used Prime + in combination with MH last season, Gooden says.