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A36-L«ncMtef Farming, Saturday, July 5, 1997
Tobacco
(ConUnuad from Page A 1)
against the blue mold.
Anderson and Yocum said to a
group of at least ISO that the strain
of blue mold currently in Lancaster
County is believed to be a
Ridomil-resistant variety that is
also believed to have been intro
duced a month ago through two
shipments of transplant-size tobac
co plants from North Carolina.
Ridomil is also a fungicide,
which had been approved for use
in seed beds for tobacco. A new
version of the fungicide, Ridomil-
Gold, has not been approved for
use in seed beds because some blue
mold has become resistant.
Some businesses in Southern
states such as Florida and North
Carolina have developed that
emphasize raising tobacco plants
in floating seed beds.
The seed bed medium floats
above water and the moisture is
wicked up to the seed and plant
The warm, and constant moisture
environment presents optimum
conditions for the growtl\ of fun
gus. Ridomil use allowed growers
to use the floating beds to produce
a higher number of quality tobacco
plants for sale for transplanting
into fields.
However, with the constant and
widespread use of Ridomil in the
floating beds, the blue mold deve
loped resistance.
Therefore, the newer version of
the fungicide can no longer be used
in seed beds, although the remain
ing stocks of the older version of
Ridomil are still labeled for such
use.
During a spring tobacco meet
ing, Yocum and Anderson had
warned local growers about pur
chasing and using transplants that
may possibly carry the resistant
variety of disease.
Apparently, their warnings were
not completely heeded.
Yocum said that while blue
mold is not a surprise disease in the
area, the traditional variety (which
continues to be controlled by
Ridomil in the field) normally only
appears in the state later in the
season.
He explained that the micro
scopic spores of the blue mold
become airborne and travel north
and east, carried with storms.
The prevailing wind patterns in
North America usually take the
shape of a giant “U” stretching
from the Northwest down south
through the Mid West or further,
and then back up into the
Northeast
Through the seasons, the post
ion of the “U” changes north and
south across the continent. The
“U” generally travels north and
south, as the earth changes its rela
tionship to the sun.
Here, in central Pennsylvania,
sometimes storm systems travel
off the East Coast farther south and
sometimes farther north.
Sometimes the northeast direc
tion of the “U” remains to the west
of central Pennsylvania, taking a
course up the Ohio Valley, through
northwest and northcentral
Pennsylvania.
Blue mold cannot tolerate cold
temperatures and only overwinters
in southern North America, such
as in wild tobacco in Texas, in
southern Florida, in Cuba, and in
South America, Yocum told the
group.
The spores (the “seeds” of fungi
are called spores) are carried with
the wind and generally creep north
and eastward as the “U” dips farth
er south as the summer progresses.
Some years central Pennsylva
nia is spared, other times not
Growers
States involved with tobacco
production have long recognized
this relationship between the
spread of airborne disease and
weather patterns and have set up a
reporting system, so that the
spread of disease can be antici
pated and growers can take appro
priate action.
Ycoum said that some of the
other states involved with monitor
ing diseases have also had the dis
ease. though they have both types,
resistant and nonresistant.
The nonresistant variety is usu
ally the first one to show up, car
ried by the winds and steams. It
was not yet detected in Pennsylva
nia and the weather was recently
not conducive to its movement
here.
That is part of the reason why
officials believe the blue mold was
transported into the state through
contaminated tobacco transplants
trucked into the state.
Yocum said that this year the
fungus appeared very early in Flor
ida and jumped north.
“We would have gotten it any
way, because it travels with storm
fronts,” Yocum said. “All (that
happened with transporting
infected plants) was hasten deve
lopment of the disease.”
In order to fight this fungus, the
Pennsylvania Department of Agri
culture petitioned for and received
emergency approval for the off
label use of the Acrobat MZ
fungicide.
According to Yocum, most of
the transplants from North Caroli
na did have the blue mold. Since
then, Anderson said he has been on
SO to 60 farms and said he can find
it in almost every seed bed.
He said that if the rains come as
had been forcast that it could soon
be everywhere in the county.
It started raining during the
meeting.
Nonirrigated fields in the region
have been very dry, causing some
spiking of com. Tliat has kept the
mold from becoming widespread
in fields.
The mold spores can fall with
the rain and need the moisture on
the surface of the tobacco leaf in
order to grow.
The disease causes spotting and
browning of leaves and the dam
age is irreparable, though the fun
gicides can stop further damage.
According to Yocum, there are
two fungicides that can be used
Dithane DF as a preventative, and
Acrobat MZ which has preventa
tive and limited systemic
properties.
(Dithane is in the mancozeb
family and it is also in Acrobat
MZ.)
The systemic properties of
Acrobat MZ can kill the mycelium
(the actual body of the fungus that
is generally not seen) in the plant
and thus has some curative proper
ties, but it’s only systemic locally.
Both Acrobat MZ and Dithane
DF have strong preventative prop
erties because they kill the spores
when they land on the leaf.
The fact that the main strategy
for fighting blue mold depends on
interacting with the disease on the
surface of the plant means that
spraying techniques need to ensure
complete plant coverage.
Sprayers will probably need to
have different nozzles and arms
attatched in order to effectively
coat the plant
Many of the tobacco growers in
the region use mule power, and
Anderson and Fleming rigged
Beiler’s boom sprayer to tackle
eight rows.
Starting with a boom sprayer
(Turn to Page A 37)
Keys to Success for Controlling Blue Mold in Tobacco
with ACROBATMZ
s Initiate ACROBAT MZ applications as recommended by the Blue Mold Advisory
Use ACROBAT MZ in a preventative foliar spray program to manage blue mold
v Direct application of ACROBAT MZ to the plant (not the soil) and provide thorough
coverage over leaves and bud of plant
Use hollow cone or disk-core nozzles to break spray into small droplets for thorough
plant coverage
s Use multiple nozzles per row that direct the spray over the entire plant
s Add drop nozzles as the plant grows to insure thorough plant coverage
v Use high volume sprayer
v' Spray pressures greater than 100 provide <he best results
s Spray only as many rows pet pass wit), the sp'ayoi as the ec.uip.n j ■< will effectively
deliver fungicide to the target leaves.
Make application to dry foliage ACROBAT MZ is ramfast in 3 hours
•s Keep the spray interval close (5-7 day intervals) under strong disease pressure
Refer to ACROBAT MZ product label for complete application and rate details
Application Rates and Timing for Blue Mold Control
with ACROBAT MZ in Field Grown Tobacco
Weeks of Growth Rate of ACROBAT MZ Water Output
After Transplant (Pounds of Product/Acre) (Gallons/Acre)
Recently transplanted to 5 2q
3 weeks after transplanting
3- weeks after transplanting n
(knee high) _
4- weeks after transplanting _ „ n
(waist high) _ _
6-7 weeks after transplanting _ fln
(chest high) _
7 weeks after transplanting _
... 2 o iuu
and beyoad
Note Above directions are for dilute sprays If concentrate sprays are used, adjust rate and
volumes proportionately
Application to Small Plants (transplanting up to 3 weeks)
♦ Use one hollow cone nozzle over the
♦ row and one on each side of the plant
♦ Apply 20 gallons per acre of water
volume
♦ Spray at pressures above 60 PSI to
achieve good droplet dispersion
The Cost Of Spray Nozzle Conversion
8 Rows = 9 Drops on existing Boom Sprayer Modification Costs
Existing spray boom had 15 spray nozzles on 20 inch center to cover 285 inches (23 75 feet)
Modified spray boom has 17 spray nozzles on 19 inch center to cover 304 inches (25.33 feet)
Drops
Part No Description Quanity Unit Costs Total Costs
2135415NY8 15" Hose Drops
8600214NY8 Swivle Bodys
DVP6 Orifice Disc
DC23NY Core
8079PP50 Strainer
33942 Nozzle Blank Cap
Rows
DVP6
DC23NY
8079PP50
3NTTI2
33942
3812
AA11134
Total Cost = $126.41
Cost / Row = $15.80
This cost information for converting to cone spray nozzles to ensure top ana bot
tom tobacco leaf protection when spraying the Acrobat MZ product was compiled by
Lancaster County Penn State Extension Agent Robert Anderson and Mike Fleming,
with American Cyanamid, makers of Acrobat MZ. Compared to the value of the crop,
the cost for purchasing the proper spray heads is miniscule. While the specific spray
head manufacturers are in no way endorsed by Penn State, these were selected
because they will perform the Job. In addition, according to John Lake, with the Pen
nsylvania Department of Agriculture Bureau of Plant Industry, while Acrobat MZ was
similarly approved for use against blue mold last year (though it wasn’t really needed
because weather patterns protected the area), it was approved this year with the sti
pulation that spraying equipment provide complete plant coverage. The Acrobat MZ
has only local systemic properties and new tobacco plant growth is not protected
unless it too is sprayed. Acrobat MZ stops spoliation, and thus can stop the blue
mold, which is believed to be a variety already resistant to another common fungicide,
Ridomil.
Orifice Disc
Core
Strainer
Nozzle Tee
Nozzle Blank Cap
Poly Nozzle Nut
Clamp
lip vf'
$3.8250
$4.9500
$0.5700
$0.6225
$0.5325
$0 1600
1 6
1 6
1 6
$0.5700
$0.6225
$0 5325
$0,4200
$0.1600
$0 0800
$2.1975
$34.43
$44 55
$9.12
$9.96
$8.52
$0.32
$lO6 90
$4 56
$4 98
$4 26
$0.84
$0.32
$0.16
$4.40
$19.52