PLANT & SOIL SCIENCES FACT SHEET TOB-5-05
Drowning, Wet Feet,
& Blow Over
By Gary Palmer, Extension Tobacco Specialist
is not native to
rainfall can stress a tobacco crop at any stage of growth, creating a
poor root system if it occurs early in the season.
In some cases, tobacco may have a delayed response and go down
only after sunny conditions returned.
While drowned tobacco will go down quickly after about 12 hours
of standing water, a slower decline is an indication of “wet feet”.
“Wet feet” is simply a degree of drowning where a plant
sustains extensive root damage, but may not flop.
An examination of the root system may reveal dead or otherwise
damaged roots. A cut through
the surface of the stem will expose a vascular system that has brown or
dead tissue (picture below left). Tobacco
with “wet feet” may recover at night, but droop again during the
heat of the day.
Tobacco that recovers may not be a sign that the tobacco will make
a substantial recovery, but an indication that a farmer has some time to
decide what to do. Tobacco
that is not yet topped has little future and must be cut if anything is
to be salvaged. A decision
must be made to determine if the return will be worth the expense.
It may not be. Tobacco
closer to harvest should be harvested fairly quickly to prevent further
A tobacco leaf that is wilted will not transpire at the normal
rate. Transpiration is the
evaporation of water from the leaf surface that cools the leaf, thereby
preventing sunscald. However,
if transpiration cannot occur on the wilted tobacco, sunscald may damage
the leaf resulting in a green stain as the tobacco cures.
Since sunshine will remove the green, a waiting period of at
least three days between cutting and housing is necessary in sunscald
cases. If no sunscald
occurs, no delay is necessary. Too long of a delay in any case may allow
rot to develop increasing the chances of more rot once the tobacco is in
the barn. Flopped tobacco
may also have a leaf breakage problem and a field wilt of a short
duration after harvest may be needed to increase leaf retention.
Again, rot is an issue and weather conditions need to be
If high winds accompany the rainfall, blow over may occur along
with the root damage. Lodged
or blown-down tobacco can be difficult to manage.
It may be impossible to get spray equipment through the field
without damaging some of the tobacco and suckers may start to grow on
exposed stalks. Rundown type
chemicals including Prime+, Butralin or any of the fatty alcohols alone
are not advised since they depend on an upright stalk for complete
coverage. Maleic Hydrazide
(MH) containing products that have a systemic action are needed to
achieve some level of control. Bacterial
and fungal rots are common on the underside of the plant near the ground
where ventilation and drying are prevented.
Hanging tobacco with rot may increase the chance for further
damage in the barn.
Occasionally farmers will try to set up blown-down tobacco.
Although labor intensive, this may work with favorable weather
following the blow over and if root damage is minimal.
However, if more wind and rain are forecast, there is no point in
setting the tobacco up to have it fall over again.
Obviously, economic returns must be considered prior to any
attempt to stand tobacco up after a blow over.