TOBACCO NEWSLETTER
by
Roger N. Cobb
Agricultural Extension Agent

Tobacco Test

We have a sucker control test in conjunction with NC State University on the Eddie Ross farm. We are evaluating various contact and systemic materials. The data will be summarized and published in the 2005 Tobacco Information Book. The state tobacco trou made a stop at this test plot on July 13. They visited a black shank test on the Mike Herbin farm in Rockingham County before stopping in Alamance County. The results from these tests will be summarized in either the 2005 Tobacco Information Book and/or Dr. Tom Melton's Tobacco Day.

Crop Conditions

Our crop started off with some dry soil conditions and put down a good root system. Rains came after a few weeks and most tobacco really took off and grew. Up until these days of 90 degrees F. heat came, the crop looked excellent. Now the heat has taken a toll on the tobacco and you can definitely see a change in the overall crop. Dr. David Smith said the crop looked good over the entire state but a lot of eastern North Carolina tobacco grew fast and was thin and was coming off of the stalk in a hurry. If ours will get body in it, we might find ourselves in a better position than some other areas of the state.

We haven't been without some problems this growing season. Pythium attacked a couple of farms killing some plants early on up until knee high staet. Pythium is in the soil at all times so we really don't know why it attacks plants when it does. It basicallly looks like black shank so you have to send it to teh disease lab to determine if it is pythium. Black shank has begun to show up in some fields in the county. Last year was not a big black sshank year and 2004 hasn't been as of yet. Things could change. Granville wilt has showed up in the county and has caused a big problem in an adjoining county. Target spot is working on some leaves even in this heat. Nematodes are working on some root systems in teh county. Be sure to check root systems when stalks are destroyed in the fall.

Sucker Control

Soil moisture has become a problem at topping time. Early contact treatments on tobacco seemed to work well because the suckers were tender. Some of the later topped tobacco may need some added moisture for the MH to be taken up the way we would like. The most widely used sucker control program is a mixture of MH and flumetralin (Prime + or Flupro) following two contacts. This usually does a good job but dry conditions at MH application time might effect these results. Hand applicatoin of flumetralin is still used but is not popular as it was a few years ago.

There are provisions for control of late season sucker regrowth but with restrictions. You can apply a contact 3 to 4 weeks after MH application if control is starting to break down. This will not control suckers more than 1 inch long. Do not make more than three applications of a contact per crop per season. Flumetralin can be used to control late season suckers but it has a restriction as well. It can be applied 3 to 4 weeks after MH application but will not control suckers over 1 inch long. Do not use for late season sucker control if used earlier in the season.

Curing

Before beginning to cure your crop, you need tomake any annual maintenance adjustments recommended for the burner and/or heat exchanger. The burners should have the correct amount of excess air established to get complete burning of fuel and the highest combination efficiency, resulting in reduced fuel consumption. When too little air is present, the burner will smoke. Smoke not only wastes fuel but can deposit soot inside the heat exchanger where it acts as insulation. Even a thin coating of soot can reduce the heat exchanger efficiency. When too much air is present, the excess air cools the combustion gases and carries heat out before it can be caputred by the heat exchanger. Also, the correct burner firing rate (BTU per our) should be checked annually. Typically the burner firing rate is 400,000 to 500,000 BTU per hour, depending on the amount of green tobacco loaded, fan output and other factors. A burner that is firing at too high a rate can overwhelm a particular heat exchanger design, resulting in higher thermal stress and the increased risk of developing cracks in the heat exchanger. The burner/heat exchanger system will operate most efficiently when the burner is operating at the lowest capacity that will allow the barn to maintain the desired temperature.

Successful and efficient bulk curing depends on: uniform loading of racks or boxes, adequate airflow, proper control of the curing conditions, and a well maintained and energy efficient curing barn.