xt79kd1qh755 https://exploreuk.uky.edu/dipstest/xt79kd1qh755/data/mets.xml   Kentucky Agricultural Experiment Station.  journals kaes_circulars_004_499 English Lexington : The Service, 1913-1958. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Circular (Kentucky Agricultural Experiment Station) n. 499 text Circular (Kentucky Agricultural Experiment Station) n. 499   2014 true xt79kd1qh755 section xt79kd1qh755 3 L EI H O S S € S i I I I 3
BI rk Sh k L ' I95`  
J By J.\II/. Irvine and W. D. Valleau
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Circular 499
  Cooperative Extension Work in Agriculture and Home Economics
  College of Agriculture and Home Economics
  University of Kentucky
li. and the
6 U.S. Department of Agriculture, cooperating
x FRANK J. WELCH, Director
i Issued in furtherance of the Acts of May 8 and June 30, I9I4.

 CONTENTS
Page
Summary .................... 3
Recommendations For Farms With Only One
Field Fit for Tobacco ............ 4
Recommendations For Farms With Two Fields
Fit for Tobacco, One Which‘Was Infested in
1951 ........... . ......... 4
Recommendations For Farms With Three or
More Fields Fit For Tobacco ........ 4
Clean Land and Clean Tools the Solution . . . 5
How Long Does the Black Shank Fungus
Live ........ . .......... . . 6
. Don't Allow Land to Become Heavily
Infested ........... . ...... . 7
Tobacco on Flooded Land .......... . 7
Limestone and Carryover of Black Shank in
the Soil ................... . 8
Selection of a New Field for Tobacco .... . 8 _
Precautions Against Contamination of the
New Field ................. . . 9
. Selection of a Site for the Tobacco Bed . . . . 10
Grow Your Own Tobacco Plants ........ 10
7 Setting the Crop .......... . ...... 10
Tobacco Stalks and Barn Sweepings ...... ll
. Black Shank and Irrigation ...... . .... ll
_ Visiting, Trading Labor and Tools, and
Measuring Tobacco Acreage. ...... . . U
‘ How to Recognize Black Shank ....... . . 12
2

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. , Q
,#/> 3
l SUMMARY
Prevent losses from black shank in 1953 by -
 
1. Placing the plant bed on clean land that is not
likely to be contaminated by road water, wash from in-
. fested land, or wash from the tobacco barn.
Z. Grow tobacco on land in 1953 that has never
had black shank on it, and land that is not likely to be-
come infested by running water from roads, infested
fields, or any other source.
3. Prepare the bed and the tobacco field with
tools that have been thoroughly cleaned, so that the
black shank fungus will not be introduced on clods of
dirt.
4. If you trade labor or tools with your neighbors,
be sure that all tools are thoroughly clean before mov-
ing from one farm to another, and be sure no dirt is
· carried from one farm to another on men‘s shoes or
on the hoofs of animals or in any other way.
5. Use water for watering beds and setting to-
bacco that has no chance of contamination with the
black shank fungus. Water from creeks and rivers
is not safe.
6. If any black shank plants do develop, remove
themwith all of the roots possible and drench the spot
thoroughly with 1-400 nabam solution.
7· Do not allow a field to become h€B.VilY infest-
ed with the black shank fungus by growing tobacco in
infested-ground or by leaving infected plants and roots .
in the field. Remove them as completely as possible.
3

   I .·* ' " `“ 7 ' 5 ”’ " FW"` — . `
 
Field Fit for Tobacco
  e
1951 - Black shank  
1952 - No tobacco grown C
1953 — Grow no tobacco E
5
Note: If tobacco was grown on the infested field in 1952 {
and if all diseased plants were removed from the field as f
soon as symptoms could be observed, and the spots F
drenched with nabam, there is a possibility that carry- V
over of the fungus has been reduced and that there may E
be less loss in 1953 than in 1952; but there is at present E
no proof of this, and the grower might be taking con-
siderable risk in using the land in 1953.
Recommendations For Farms With Two Fields Fit For
Tobacco, One of Which Was infested in 1951 b
Field 1 Field 2 Z
1951 - Black shank 1951 - Grass 1
1952 — No tobacco 1952 - Tobacco 0
. 1953 — No tobacco 1953 - Tobacco, if 1952 crop g
was free from black 1,
shank O
. Recommendations For Farms With Three Or More —
Fields Fit For Tobacco U
` Fields infested with black shank should be in grass or  
other crops until experiments show it is safe to plant Q
them to tobacco. In 1953 grow tobacco only on clean land.
lf there was no black shank whatever in the 1952 field, it
_ should be safe for another crop in 1953, provided pre- b
cautions are taken not to contaminate the soil. C
_ » s
t<
` c
fi 4

 PREVENT BLACK SHANK LOSSES IN 1953
By J. W. Irvine and W. D. Valleau
One season has passed since Kentucky tobacco grow-
ers made a state -wide attempt to stop losses from black
shank. The results have been spectacular and have
demonstrated that a careful farmer who has enough land
so that he can change the location of his tobacco from
year to year if black shank develops, has little to fear
952 from the disease. No satisfactory way has yet been
das found to prevent losses on farms where there is only one
Ots plot of ground satisfactory for tobacco, and this infested
_ry_ with the black shank fungus. It is too early to know the
may effect of removal of diseased plants and spot-drenching
Sent with nabam on carry-over of the black shank fungus in
.On_ fields used for tobacco each year.
Clean Land and Clean Tools the Solution
EE- Reports have been gathered on 1,183 farms   that had
black shank losses in 1951 but where tobacco was planted
on clean land in 1952 2/. On 932 of these farms, or 79 of
each 100, there was ng loss whatever from black shank in
1952. Where black shank did occur on clean land, usually
only a few plants were affected. Where tobacco was
3TOP grown in 1952 on land where losses occurred in 1951,
lack losses were sometimes heavy in spite of the drouth that
occurred over most of the state.
 
i   These figures are based on answers to a question-
naire sent to county agents and filled out by them. In
is Or §0me cases their answers were based on actual records;
nant U1 Others, on estimates. Enough accurate records were
and. Oblialned to indicate that the estimates are conservative.
M li   By clean land is meant land that has never had a
pre b1&Ck·shan.k—infected crop of tobacco on it. Reports fI‘OI`I`1
C0unties with a long history of black shank $¤gg€S13 that
some of the growers moved from a recently infested field
to one where there was a carry-over from an infected
crop some years previously, and so failed to get control.
5

 z »·{,  .
A total of 393 farmers reported black shank on their
farms for the first tixne in 1952, but it is probable that
on most of these farms there was some black shank in
1951 which was either not reported or not recognized.
If these farmers, in addition to those who successfully
controlled the disease in 1952, will go to clean land and
take necessary precautions not to contaminate the new
field, losses from black shank need be very little in 1953.
How Long Does the Black Shank Fungus Live?
A year ago there was no definite information as to how
long the black shank fungus would remain in the soil after
a diseased crop. In 1952, studies were made on2'? fields
out of tobacco 1, 2, and 3, years following a severe out-
break of black shank.
A One year without tobacco was not long enough to get
rid of the disease on any one of 12 fields studied, although `
on several farms losses were much less in 1952 than in
. 1950. On 4 of these fields losses in 1950 ranged from 30 4
to 90 percent, with an average of 55 percent, while in1952
the range was from 2 to 40 percent, with an average of Q
21.1 percent. `
` Two years without tobacco gave variable results. ‘
Losses were recorded on 11 fields where the loss in 1949
l ranged from 7 to 66 percent. In 4 of the fields there were i
A 0, 1, 4, and 54 plants, respectively, that developed black l
A shank in 1952. In another field the loss dropped from 50 l
` to l. 6 percent; while losses in the other 4 fields ranged ‘
_ from 17. 6 percent to 80 percent. ln half of the fields a ]
commercially satisfactory crop could have been grown, at J
· least in a dry season, but the loss in the others was too [
great to warrant taking a chance on land only 2 years I
without tobacco. 3
· Three years without tobacco was studied on only four
_ · farms. On two fields a single black shank plant was
found on each, one field dropped from a loss of 90 percent ,
A in 1948 to 1. 3 percent in 1952, and the fourth field E
Y 6

 1‘ dropped from 25 percent to 4 percent. In any of these
t fields a satisfactory commercial crop could have been
.n grown, provided that immediate removal of affected
1. plants will prevent current—season spread to neighboring
.y plants in a wet season.
Ld
W It is obvious that even with 1 year out of tobacco there
3_ is a great falling off in inoculum, but the time required to
completely rid a field of the fungus is not yet known.
As a result of these studies, recommendations can be
W made for 1953, based on the length of time the field has
ir been without tobacco. See page 4.
s
t` Don‘t Allow Land to Become Heavily Infested
The more crops of tobacco grown on a piece of land
at infested with black shank, the more heavily the soil will
gh become loaded with spores of the fungus and the longer it
in will take to get rid of them. Therefore, on the very first
gg appearance of the disease, remove the diseased plants as
52 soon as they can be recognized, taking up all roots
of possible, and then dreneheach spot thoroughly with 1- 400
nabam solution (3 tablespoons of nabam to 10 quarts of
water). If a field has many diseased plants the nabam
;_ ` treatment may be too tedious and expensive, but it would
49 still pay to remove every tobacco plant, with as many
re roots as possible, as soon as it is recognized that it has
Ck black shank. If this is done carefully, taking out all roots
50 POSSib1e, it is certain to reduce the amount of fungus
ed spores that can be carried over. The field should then
a be sown to grass and not used for tobacco until experi-
at ments show it is safe. If any other ground is available,
OO don't risk planting a field to tobacco the year after black
rs shank is found in it, even _though there were only a few
Plants and these were remo_ved and the ground drenched
with nabam solution.
ur Tobacco on Flooded Land
as S€V€I‘&1l fields were found in 1952 that had had black
Ent Shank in the past but had been flooded in W inte 1* OI`
dd Spring by high waters of a creek or river. These flooded
7

 fields, when put back to tobacco, usually had few or no
black shank plants below the high-water line, but in
several instances had black shank above the high—water
mark. While there is no absolute proof that flooding will
t always get rid of the fungus, it now appears that flooded
land will be safer to use after a couple of years without
tobacco than land that has not been flooded. Flooding, if
it introduces the fungus, does not contaminate a whole
field with black shank; it may leave a few contaminated
roots or stalks in the debris at the high-water mark, and
these may result in a few affected plants in the next crop.
Limestone and Carryover of Black Shank in the Soil
Studies on the reaction of the soil, whether acid or
alkaline, as determined by pH, suggest that fields on which
the pH concentration is high (that is, 6. 5 or above) are
_ more likely to carry the fungus from year to year than
soil more distinctly acid (pH 5. 6 or below). The mo s t
serious losses from black shank appear to be on parts
of fields where much limestone rock, as small particles
or large pieces are scattered through the soil.
Until more is known about the reaction between lime-
stone particles and carry-over of black shank, it may be
well to put spots in fields that are known to contain lirne,
. such as drainageways from old lirnestone roads that pass
across a field, in grass permanently, even though the re-
mainder of the field is plowed for tobacco. Fields that i
have been heavily ··limed for alfalfa may be found to carry j
i the black shank fungus for longer periods than more acid *
. soils. There is no absolute proof of such a relation be- .
tween limestone and black shank, but several observations
` make it seem probable, and it may be safer to use the _
._ more acid soils for tobacco. These observations al so  
suggest that limed soils should be left out of tobacco (
longer than acid soils in getting rid of the fungus. I
e   ’
. I
_ — Any farmer who had black shank in 1952 should select l
a clean field (that is, one that has not had a black shank I
e

 Z affected crop on it in the past) that does not receive any
1_ drainage water from a black shank field or, if it does,
u the waterway across the field should be left in grass
_d above the high—water mark. The new field should not be
gt along a road if the field is lower than the road and r e-
if ceives drainage water from it, unless all of the road
Le water can be carried across the field on a sod waterway.
_d lf the field is about level with the road, a strip of' s od
Ld about 20 feet wide should be left between the road ditch
and the tobacco. This will tend to filter out the fungus
p` that may be in the ditch water when it overflows the sod.
The field should not receive drainage water from a barn -
yard or the yard around a tobacco barn; and it should be
or so located that no one has to cross a contaminated field
;h to reach it. It has been observed that when an old
re tobacco bed site is plowed, along with a clean piece of
an ground, black shank sometimes starts at the old bed
St site. It Amay, therefore, be safer not to plow old bed
ts sites for cropping tobacco.
65 Precautions Against Contamination of the New Field
e- The black shank fungus is carried in running water
be but also in clods of dirt on shoes or horses' hoofs, and in
ie, dirt clinging to all kinds of machinery. To prevent con-
_5s tamination ofa new field, it is necessary that all tools
·e- that have been used in a black shank field be cleaned of
1at dirt as thoroughly as possible before preparing the new
·ry plant bed and the new field. Thorough soaking of tools
zid with 1-400 nabam solution should be helpful, provided all
,€- soil masses on the tools are thoroughly wetted.
ms It is so important that the machinery be clean that a
the farmer can afford to give careful thought to the best
SO methods to be used under his conditions. It is better to
ico do the cleaning on a grass plot rather than in a tobacco
barn or in a barnyard where the tools may be contami-
nated again by the dirt left on the ground, and it is also
better to do the cleaning as near the old infested field as
ect P0$Sible so as not to distribute dirt from the black Shank
lnk field Over the farm, It would be highly deSi1'&bl€ for
each farmer to make a practice of cleaning all of his
9

 machinery· in the fall before storage for winter, so that V
this work need not be done when the weather is satisfac— V
tory for plowing and fixing the ground. 5
t
Selection of a Site for the Tobacco Bed
There is danger, on a farm where black shank
occurs that infested soil may be carried to the plant bed
site during the pulling season. It may, therefore, be S
safer to choose a new site each year. The tobacco bed b
should be placed where it will receive no drainage from a 8
black shank field and where dirt from the barnyard or f'
tobacco barn is not likely to be carried to it on the feet of a
anirnals or men. It should be located where it can be O
reached without walking across a black shank field. The P
bed should be prepared with clean tools. If watering is
necessary, the water should be from a cistern, well,
spring, a pond that does not receive drainage from a
black shank field, or a city water supply; not stream or T
river water. b`
Grow Your Own Tobacco Plants ti
ox
Make your plant bed large enough and care for it V*
well, so that you will not need to get plants from another ti
farm. In case of a plant bed failure in a black shank area
in Kentucky , a grower would be much safer to go to a
black—shank-free area for plants, but should take every
precaution not to carry black shank to the farm from
which he gets the plants.
01
Setting the Crop C2
sl
Make every effort to see that all tools used in set- Sl
ting are as clean as possible before beginning work, di
particularly if they are borrowed tools that have been th
used on a black shank farm. The grower should see that S}
the shoes of the setters are free from clods of dirtbefore
entering the field, particularly if the Setters are hired
labor from a farm where black shank was present the ei
year before. Black shank can be introduced in setting b‘
10

 at water if it is taken from an infested creek or river. Pond
c__ water, if the pond receives no drainage from a black
shank field, cistern water, spring water, and water from
town or city water supplies should be safe to use.
Tobacco Stalks and Barn Sweepings
nk  
ed Tobacco stalks and barn sweepings from a black
be shank crop should not be used as bedding and should not
ed be put on the manure pile. They may be burned or put on
1 a grassland that does not drain onto land that is to be us ed
Or for tobacco or into a creek or river, if such land is
of available; or they may be put back, during a dry period,
be on the field from which they came if it has been sown to
.h€ permanent grass.
is Black Shank and Irrigation
all,
a Tobacco beds should not be watered from creeks or
_OI. rivers, as at that time of the year the water is likely to
be contaminated. It is also probably dangerous to irri-
gate tobacco fields soon after setting the crop, par-
ticularly if the water is high. However, at the low stage
of rivers during a drouth, when irrigation is particularly
it valuable, it is probable that the water is free from con-
hel. tamination and safe to use for irrigation.
rea
O a Visiting, Trading Labor and Tools,
ery and Measuring TobaccoAcreage
om
Black shank can be carried from one farm to another
on shoes, automobile tires and fenders, on the floor of a
car, and on all kinds of machinery. Visitors from black
Shank farms, when visiting other farms, should first be
set- sure that their shoes are free from dirt and that clods of
irk, dirt are not on the floorboard ready to be kicked out when
een théy get out of the car. As an added precaution, visitors
that Should stay entirely away from the tobacco field.
Yore
;red In areas where labor and tools are traded, the great-
the est of care should be taken to see that all tools are clean
ting b€fO1`€ they leave a farm; and the farmer on whose farm
ll

 the tools are to be used should assure himself that they ‘
ire clean before he allows them to enter his farm.
Black shank could be carried from farm to farm by  
those who measure tobacco acreage for P, M. A. The A V
P. M. A. has recognized this danger and has instructed  
that measurements of fields infested with black shank be `  
made outside the field, and that infested farms be left  
last and then be measured only when the ground is dry.  
Another suggestion is that the measurers wear overshoes  
or boots which may be removed and washed before leav—  
ing the farm. (Letter 2241, August 9, 1951, State  
P. M. A. Committee to chairmen of county P. M. A. com- A  
mittees) . .  
How to Recognize Black Shank  
Black shank causes tobacco plants to look as though  
they had been drowned; and many growers, in the wet ’   
season of 1950, mistook a few plants that were dying from  
black shank for drowned plants, only to put the field back   ‘
in tobacco in 1951, with heavy loss. The fungus that  
causes black shank lives through the winter in the soil    
and attacks tobacco any time during the summer.    I
The first signs of the disease are a slight wilting,
followed by the lower leaves turning bright yellow and
hanging down the stalk. At the early wilting stage it may  
be necessary to cut into the underground base of the stalk
to find the blackened, diseased area; while later the roots •
usually will be .found to be dead and a black rot may have  
spread up the stalk for several inches. lf the stalk is
split, the rot will usually be found to have entered the
pith, which is dark and separated into disks.
{ L
Lexington, Kentucky February, 1953 n
12