Why 2016 Tobacco Is Not Holding Better

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The question of the past two weeks has been, “Why is my tobacco burning up in the top of the plant?”  I have been curious about this condition that has been observed in most fields, and after some consideration and observation I feel that this situation has been influenced by many factors. This is to say that there is not a single answer to this question of why but rather many answers and many reasons. The following are some of the factors that I feel are contributing the most to deterioration of upper stalk tobacco in our area.

1. Environment – This is a broad term that encompasses many different factors. To be more specific, our tobacco crop grew in a very tender state up until layby. In addition, these tender growing conditions have resulted in leaves that are a bit more thin than normal. Most fields were well watered and the crop did not suffer from stress early. However, after layby we experienced significant stress periods followed by periods of rain and we suffered from a very hot and dry August with many days in the mid 90’s. During these hot dry periods tobacco was wilting and upper leaves were bronzed in the intense sunlight.

2. Leaf Diseases – Beginning in July we witnessed fairly high pressure from target spot (Rhizoctonia) on the lugs and some cutters. In addition, during this period brown spot caused by (Alternaria) also began to affect some lower leaves. Brown spot is an opportunistic disease that affects plant tissue that is already in decline for one reason or another. Therefore, leaves that are thinner that normal, affected by sunlight, or affected by other pathogens like target spot are more susceptible. Beginning in early August, we began to see a fairly high amount of frogeye leafspot in tobacco. Frogeye is caused by yet another pathogen, Cercospora. At the present time there is at least some frogeye and brown spot in most of our tobacco fields and they are affecting leaf quality and holding ability.

3. Root and stalk health – At this time of the year we have diseases and other conditions that are affecting the overall health of tobacco roots and stalks. In recent days I have examined roots and stalks of plants on which the leaves are deteriorating more rapidly. In these cases I am finding pathogens like Granville wilt, tomato spotted wilt virus, and southern stem rot. Furthermore you can also find galling from root knot nematode in some fields. Whenever the roots or stem of the plant are affected, then the leaves will deteriorate more rapidly.

4. Soil Type – While soil type is definitely part of the environmental conditions, I felt in this case it may be worth more explanation. At the present time tobacco on deep sandy soils appears to be in better condition than tobacco on heavier and wetter soils. When I think about deep sandy soils in our area, the Wagram soil series immediately comes to mind. On the continuum of lighter to heavier soils you have Wagram, Norfolk, Goldsboro, Lynchburg, and Rains. Right now the better drained soils are showing less Granville wilt and less Black Shank. In addition the tobacco roots in these soils have an overall more healthy appearance with less necrosis (brown tissue). We all know that tobacco roots need good drainage. Tobacco needs to be on a high and wide bed for good drainage. Evidently on some of these heavier soils we have had enough moisture at some point in the season to affect root health. Tobacco roots must have excellent drainage to insure adequate oxygen in the root zone at all times.

5. Hermine – Initially I felt that Hermine helped us far more than causing any damage. However some growers have reported gusty winds and we certainly received good rainfall. Mature tobacco that is blown in the wind will release ethylene that will hasten the ripening process much like spraying a ripening agent. This could be influencing our tobacco some. Also some of the leaves that are burning the worst in the upper part of the plant are broken or damaged. I have found broken midribs and weak leaf axils in recent days.

These are my thoughts about the crop at the present time. The best management at this point is to barn the ripest tobacco and keep the barns full. If we can offer any assistance, please call 919-989-5380.

Written By

Photo of Bryant Spivey, N.C. Cooperative ExtensionBryant SpiveyCounty Extension Director (919) 989-5380 (Office) bryant_spivey@ncsu.eduJohnston County, North Carolina
Posted on Sep 15, 2016
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