Download Tobacco Tips – June 2016

Bertie County
Tobacco Tips
Jarette Hurry
June 2016
Topping tobacco in the button stage (soon after the flower begins to appear) rather than late increases yield and body if suckers are controlled. When tobacco plants are not topped for three weeks after reaching the button stage, yields are reduced by 20 to 25 pounds per acre per day, or close to 1% per acre per day when normal yields range from 2,000 t-­ 2,500 pounds per ace. Contacts (Fatty Alcohols) The first contact application should be made as soon as 50% to 60% of the plants have a visible button. Timing of Chemical application is i mportant because neither contacts nor flumetralin will adequately control suckers longer than one inch. Coverage of leaf axils and stalk rundown are essential for contact applications. Contacts should be applied with three nozzles per row, at low pressure with 50 gallons per acre delivery volume. The suggested r ation for the first application of C8-­‐‑ C10 contact alcohol products is two gallons in 48 gallons of water; this makes a 4% solution. A 5% solution is suggested f or the second or third application; this i s 2 ½ gallons in 47.5 gallons of water. Contacts are more effective if applied three to five days apart when humidity is low and leaf axils are fully exposed. This is generally between 10am and 6pm on sunny days, except when plants are wilted and temperatures exceed 90°F. Contacts should not be applied to plants that re wet with rain or heavy dew or that are severely drought stressed. Use of Flumetralin Flumetralin should be applied like a contact solution but not until the plants are in the elongated button to early flower stage. The o bjective is to apply flumetralin so that it touches the s mall suckers like contact solutions do because, unlike MH, flumetralin does not move to sucker buds through the leaves. Flumetralin must first wet the suckers like a fatty alcohol contact before it can stop cell division like a systemic. Flumetralin should be applied like a contact solution. Even though the flumetralin label allows for application of up to one gallon per acre, the general recommendation h as been for application rates of two quarts per acre. Increasing flumetralin rates from quarts per acre to three quarts or one gallon in a single mechanical application has not consistently improved sucker control, primarily because control is so dependent on coverage of all leaf axils, which is not improved by increasing flumetralin rates. However, application of two quarts of flumetralin followed by one quart of flumetralin seven days later improves sucker control compared to three quarts of flumetralin applied in a single application. This would indicate that increasing rates o f flumetralin above two quarts per acre is only advantageous if the flumetralin is applied in a split application. It is likely that split applications reduce the number missed leaf axils. MH Unlike fatty alcohol contacts and flumetralin, MH is absorbed by leaves and moves within the plant to small sucker buds. Good absorption and systemic movement depends on having good crop growing conditions. Therefore, MH should never be applied on drought stressed crops or on those wilted by too much rain, high temperatures, or both. If soil moisture is adequate but afternoon temperatures will be high enough to cause partial wilting, MH should be applied only during the morning, starting when the leaves are just slightly wet with dew. Afternoon Spraying generally is not suggested except on cool, cloudy days when soil moisture is good. MH is absorbed more effectively by younger, upper leaves than by older, lower leaves. Therefore, MH should be applied to the upper third of the plant using the three-­‐‑nozzles-­‐‑per-­‐‑row arrangement. Most MH labels stipulate that it must not be applied before the upper leaves are eight inches long to reduce possible stunting, a discoloration called “bronzing”, or both. These abnormalities are sometimes observed when MH is applied on leaves longer than eight inches. Growth distortion of upper leaves treated with flumetralin also occurs, but less frequently than that associated with MH. Research suggests that the likelihood of discoloration and stunting from MH applications is greatly reduced when applications are delayed until upper leaves are 16 inches long. Know how much MH is in the product you use. For example, one product contains 1.50 pounds active ingredient per acre which would require 1 gallon /acre. Another product contains 2.25 pounds active ingredient per acre which only requires .66 gallons per acre. Your target rate should be 1.5 pounds’ active ingredient per acre. MH residues can also be reduced when the interval between application and harvest is maximized. The MH label states that you should wait at least s even days between MH application and harvest, with the anticipation that rain fall during this period will wash off some residues. If tobacco is ready for MH application and harvest, make every attempt to harvest first, then apply MH. Delay harvest after MH application as long as possible. It will most likely be at least seven days before the crop will be ready for another harvest. This will ensure MH free first p rimings. For More information on sucker control reference chapter 7 in the 2016 Flue Cured Tobacco Production guide Jarette Hurry Bertie County Center North Carolina Cooperative Extension 204 South Queen St., PO Box 280 Windsor, NC 27983 Email – [email protected] Phone (252) 794-­‐‑5317 Fax (252) 794-­‐‑ 5375 North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure
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State University, U.S. Department of Agriculture, and local governments cooperating.