TCN tracker : a decision-based cyst nematode management aid for Connecticut wrapper tobacco types

The

Connecticut

Agricultural
Experiment

Station,

New Haven

TCN Tracker -
A Decision-based
Cyst Nematode
Management Aid
For Connecticut
Wrapper Tobacco
Types

COMN

BY JAMES A. LaMONDIA

Bulletin 992
December 2003

AND JEFFREY J. LaMONDIA

' Chief Scientist, The Connecticut Agricultural Experiment Station
Valley Laboratory, 153 Cook Hill Rd. P. O. Box 248, Windsor, CT
06095 and ^ Undergraduate Research Assistant, University of
Connecticut, Engineering School, Dept. of Civil and Environmental
Engineering, Stons, CT.

The Need:

The tobacco cyst nematode
Globodera tabacum tabacum (Lownsbery &
Lownsbery, 1954) Stone, is a damaging
pathogen of shade and broadleaf cigar
wrapper tobacco types in the Connecticut
River Valley of Connecticut and
Massachusetts. Nematode infection of roots
can cause dramatic stunting, yield loss, and
reduce leaf quality. Plant yield losses
increase with increasing numbers of tobacco
cyst nematodes, and we have developed
nonlinear yield loss models to predict shade
tobacco (LaMondia, 1995) and broadleaf
tobacco (LaMondia, 2002) yield losses
based on preplant nematode densities in
sampled soil. Losses can exceed 40 to 60
percent at high nematode densities.
Nematode management below damaging
population levels is important in minimizing
losses. In addition, G. t. tabacum population
increase over a growing season has been
described by using a linear relation on a
log/log plot (LaMondia, 2002). Growers
can sample soil from nematode-infested
fields, combining multiple sub-samples to
result in a better population estimate, and
submit the soil to the Valley Laboratory for
analyses. G. t. tabacum populations are
reported as the number of second-stage
juveniles (J2) per cm^ in sampled soil.
These nematode densities may then be used
to predict yield loss and subsequent cyst
nematode population density. Our objective
in developing TCN Tracker was to produce
a user-friendly point and click means of
predicting the impact of various field
use/management tactics on crop yield loss
and cyst nematode population dynamics.

The Model:

Decision-based management models
have been developed for a wide variety of
pests on different crops, including, diseases,
insects, weeds, and nematodes (Flinn et al.,
2003; Kim and Ferris, 2002; Taylor and

Rodriguez-Kabana, 1999; Welch et al.,
2002; Wilkerson et al., 2002). These
models generally predict the effects of
various management options available to
producers on pest populations and crop
yields or losses. Tobacco cyst nematode
management tactics include soil fumigation,
fallowing or rotation to a nonhost crop,
planting a resistant cultivar and trap
cropping. Each management option has a
different impact on tobacco cyst nematode
populations that will be available to attack
the next year's tobacco crop. We have
developed TCN Tracker as a Microsoft
Access-based decision based management
model. Growers provide initial tobacco cyst
nematode densities determined from field
samples, click on a field use/management
option and the program calculates a
prediction of end of the season nematode
density and the potential yield loss that may
be anticipated for the next season. When
any field use/management option is selected,
the form automatically updates the end of
the season nematode density and the
potential yield loss for each of the following
years. The Access interface utilizes a point
and click form which can be printed and
used in combination with additional
sampUng over time to plan multi-year
nematode management programs.

The TCN Tracker model utilizes
population dynamics models and yield loss
functions developed for shade and broadleaf
tobacco over the last decade in field plots
and microplots and corrected for soil
volume per plant (LaMondia, 2002;
LaMondia, 1995). An inverse logistic
function (Noe, 1993; Noe et al., 1991) was
used for shade-grown tobacco (LaMondia,
1995; LaMondia, 2002) and broadleaf
tobacco (LaMondia, 2002) to represent the
relationship between harvested leaf weight
and initial G. t. tabacum density for each
tobacco type.

Y =m +

M - m

f

1 +

A

\U )

changes after tillage within 24 hours of
harvest or within 3 weeks of harvest. The
equation used for broadleaf tobacco that was
tilled immediately after harvest was:

where Y = harvested leaf weight or total
shoot weight; Pi = initial G. t. tabacum
density in J2 and J2 in eggs per cm^ soil; M
= maximum yield or shoot weight; m =
minimum yield or shoot weight; and the
parameters u and b determine the shape of
the curve (Figures 1 and 2).

Shade tobacco yield loss as a
function of initial G. t. tabacum density used
in the model was:

Loss{Yearii:) = 45.26-

1

1 +

Pi/

^220.4J J

Broadleaf tobacco yield loss as a function of
initial G. t. tabacum density was:

Loss{Year#) = 39M-

1--

1

1 +

Pi/

^220Ai J

The relationship between logio final density
(Pf) and log 10 initial density (Pi) were best
represented by linear regression and
correlation (LaMondia, 2002). The equation
used for shade tobacco population change
on a susceptible plant was:

( 0.29 Log (P;)/ 1

1.96+ «V i//

-jpjV /Log(W)

f

The timing of soil tillage after
broadleaf harvest has a large impact on the
population of cyst nematodes (LaMondia,
unpublished). Three years of data from field
plots were used to develop population

/

10

(o.068+0-«24-^« (P^

Log (10

The equation used for broadleaf tobacco that
was tilled 3 weeks after harvest was:

/

10

1.146

^0.476 -Log (P,)

Log (10 )J

The average impact of fallowing or
nonhost crop production such as rotation to
a grain on tobacco cyst nematode
populations has been a 20% decline
annually (LaMondia, unpublished). The
effects of resistant tobacco cultivars on
nematode densities were determined in field
plots and microplots (LaMondia, 2000a,
2000b). The average effect was a 58%
population decline. The use of trap crops as
a management tactic was investigated in
field plots and microplots over three years
(LaMondia, 1996) and determined to cause a
45% population decline. The effects of soil
fumigation on nematode populations were
determined in field plots (LaMondia, 1993)
and estimated at an 80% population decline.

Using TCN Tracker:

TCN Tracker is written as a
Microsoft Access database nematode
management decision aid and the Microsoft
Access program is required to use the
database. The file may be obtained on a CD
from the CAES Publications Office or by
request from James A. LaMondia, The
Connecticut Agricultural Experiment Station
Valley Laboratory, 153 Cook Hill Rd. P. O.
Box 248, Windsor, CT 06095 or by email:
from James. LaMondia@po. state. ct.us.

Transfer the file 'TCN Tracker Database'
from the CD to the computer hard drive.
Open the database on the hard drive and
then open either the 'Shade Tobacco TCN
Model Form' (Figure 3) or the 'Broadleaf
Tobacco TCN Model Form' (Figure 4) to
open the appropriate page. A title and date
may be assigned to designate the farm, field,
or other specific location and date associated
with the initial tobacco cyst nematode
population, which may also be entered on
the form. Clicking the appropriate box for
field use for years one through five then
results in an esdmated cyst nematode
population after each year and the yield loss
prediction associated with that nematode
population. When any field
use/management option is selected or
changed the form automatically updates the
end of the season nematode density and the
potential yield loss for all following years.
Each page is automatically saved for future
reference.

If the form page cannot be saved or
changed, highlight the 'TCN Tracker
Database', right click the mouse, click
properties, and remove the check in the
read-only box. The numbers generated are
predictions based on the data and models
described above and may differ from actual
nematode populations and yield losses
experienced, especially as the number of
years from sampling increases.
Environmental conditions and sampling
error may significantly affect plant growth
and nematode population changes. The
model is intended, however, as a means of
planning field use over time to manage
tobacco cyst nematode populations below
damaging levels to minimize yield losses.

References

Flinn, P. W., D. W. Hagstrum, C. Reed, and
T. W. Phillips. 2003. United States
Department of Agriculture - Agricultural

Research Service stored-grain areawide
integrated pest management program. Pest
Management Science 59:614-618.

Kim, D. G. and H. Ferris. 2002.
Relationship between crop losses and initial
population densities of Meloidogyne
arenaria in winter-grown oriental melon in
Korea. Journal of Nematology 34:43-49.

LaMondia, J. A. 2002. Broadleaf tobacco
yield loss in relation to initial Globodera
tabacum tabacum population density.
Journal of Nematology 34(l):38-42.

LaMondia, J. A. 2000a. Registration of
'Metacomet' tobacco. Crop Science
40:1504-1505.

LaMondia, J. A. 2000b. Registration of
'Poquonock' tobacco. Crop Science
40:1505-1506.

LaMondia, J. A. 1996. Trap crops and
population management of Globodera
tabacum tabacum. Journal of Nematology

28:238-243.

LaMondia, J. A. 1995. Shade tobacco yield
loss and Globodera tabacum tabacum
population changes in relation to initial
density. Journal of Nematology 27: 114-119.

LaMondia, J. A. 1993. Evaluation of
reduced fumigation rates on tobacco cyst
nematode populations and shade tobacco
yield. Fungicide and Nematicide Tests
48:216.

Lownsbery B. F. and J. W. Lownsbery.
1954. Heterodera tabacum n. sp., a parasite
of solanaceous plants in Connecticut.
Proceedings of the Helminthological Society
of Washington 21:42-47.

Noe, J. P. 1993. Damage functions and
population changes of Hoplolaimus
Columbus on cotton and soybean. Journal of
Nematology 25:440-445.

Noe, J. P., J. N. Sasser, and J. L. Imbriani.
1991. Maximizing the potential of cropping
systems for nematode management. Journal
of Nematology 23:353-361.

Taylor, C. R. and R. Rodriguez-Kabana.
1999. Optimal rotation of peanuts and cotton
to manage soil-borne organisms.
Agricultural Systems 61:57-68.

Welch, S. M., J. W. Jones, M. W. Brennan,
G. Reeder, and B. M. Jacobson. 2002.
PCYield: model-based decision support for
soybean production. Agricultural Systems
74:79-98.

Wilkerson, G. G., L. J. Wiles, and A. C.
Bennett. 2002. Weed management decision
models: pitfalls, perceptions, and
possibilities of the economic threshold
approach. Weed Science 50:411-424.

Figure Legends

Figure 1. The effect of initial Glohodera
tabacum tabacum population density in soil
on broadleaf tobacco shoot weight (g) in
microplots, 1995 to 1996.

Figure 2. The effect of initial Globodera
tabacum tabacum population density in soil
on shade tobacco shoot weight (g) in
microplots, 1995 to 1998.

Figure 3. Shade Tobacco TCN Model Form.

Figure 4. Broadleaf Tobacco TCN Model
Form.

eoao aoao

Initial G. t. tabacum density

2aao 4oao eoao

Initial G. t. tabacum density

aoao

Figure 3.

TCN Tracker - Shade

Connecticut Agricultural Experiment Station Valley Laboratory

Shade Tobacco Cyst Nematode Management Decision Model

Title:
Date:

Initial Tobacco Cyst Nematode Population:

-Year One Field Use

M Fallow [1 Fumigation

IS Resistant OH Trap Crop

M Susceptible \M Fumigation and Susceptible

r Year Two Raid Use

\M Fallow \M Fumigation

S Resistant M Trap Crop

\M Susceptible SI Fumigation and Susceptible

Population After Year 1: I
Yield Loss prediction: I _

Population After Year 2:

Yield Loss prediction:

0.0 J2/cm

0.0 J2/cm
%

0.0

0.0 J2/cm

0.0 %

Year Three Field Use 1

m

Fallow

\M Fumigation

m

Resistant

M Trap Crop

@

Susceptible

[U Fumigation and Susceptible

Population After Year 3:

Yield Loss prediction:

0.0 J2/cm

0.0 %

pYear Four Field

Use

m

Fallow

[M Fumigation

m

Resistant

M Trap Crop

m

Susceptible

[H Fumigation

and Susceptible

Population After Year 4:

Yield Loss prediction:

0.0

0.0

J2/cm
%

-Year Five Field Use

[?Z] Fallow m Fumigation

M Resistant 13 Trap Crop

M Susceptible 0 Fumigation and Susceptible

Population After Year 5: F
Yield Loss prediction: |

0.0

0.0

J2/cm
%

Figure 4.

\| TCN Tracker - Broadleaf

'I Connecticut Agricultural Experiment Station Valley Laboratory
-o^v.-.ji^*^ Broadleaf Tobacco Cyst Nematode Management Decision Model

Title:
Date:

r

Initial Tobacco Cyst Nematode Population:

r Year One Field Use

□ Fallow gj Fumigation

M Resistant B Trap Crop

11 Susceptible (Till Immediately tl Susceptible (Till Later)

Population After Year 1:
Yield Loss Year 1:

r

0.0 J2/cm

0.0 J2/cm

0.00 %

-Year Two Fieit

Jse-

[J Fallow []^ Fumigation ,

Qij Resistant M Trap Crop

K'] Susceptible (Till Immediately \M Susceptible (Till Later)

Population After Year 2:
Yield Loss Year 2:

0.0 J2/cm

0.00 %

-Year Three Field Use,

O Fallow

\M Fumigation

[Ml Resistant

M Trap Crop

[H Susceptible (Till Immediately

\M Susceptible (Till Later)

Year Four Reld Use

M Fallow

H Fumigation

(3 Resistant

\M Trap Crop

[Z] Susceptible (Till Immediately

M Susceptible (Till Later)

rtfear Five Held Use-

@ Fallow

H Fumigation

\M Resistant

\M Trap Crop

[i Susceptible (Till Immediately

\M Susceptible (Till Later)

Population After Year 3:
Yield Loss Year 3:

Population After Year 4:
Yield Loss Year 4:

Population After Year 5:
Yield Loss Year 5:

0.0 J2/cm

0.00 %

0.0 J2/cm

0.00 %

0.0 J2/cm

0.00 %

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