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Title: Incidence and distribution of fusiform rust in slash pine plantations in Florida and Georgia
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Title: Incidence and distribution of fusiform rust in slash pine plantations in Florida and Georgia
Physical Description: Book
Creator: Schmidt, Robert A.
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: 1974
Copyright Date: 1974
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Volume ID: VID00001
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HISTORIC NOTE



The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





illetin 763 (technical) March 1974




INCIDENCE AND DISTRIBUTION OF
FUSIFORM RUST IN SLASH PINE PLANTATIONS

IN FLORIDA AND GEORGIA



RUST PATHOGEN



,l |




















IRONMENT PINE-0AI


R. A. Schmidt, R. E. Goddard, and C. A. Hollis



Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
J. W. Sites, Dean for Research
University of Florida, Gainesville














Incidence and Distribution of Fusiform Rust in
Slash Pine Plantations in Florida and Georgia







R. A. Schmidt, R. E. Goddard, and C. A. Hollis











Dr. Schmidt is Associate Professor of Forest Pathology,
Dr. Goddard is Associate Professor of Forest Genetics,
and Dr. Hollis is Assistant Professor of Forest Physiology,
School of Forest Resources and Conservation,
University of Florida, Gainesville 32611








Contents


S um m ary ..................... ................... ......... .......... 1

Introduction.......................................... 2

D ata Source.................................................... .... ................. 3

A. Forest Industry Plantation Inventory Plots............................... 3
1. Container Corporation of America ...................................... 3
2. Buckeye Cellulose Corporation ........................................ 3

B. Progeny Tests of the Cooperative Forest
Genetics Research Program............................. ................. 6

C. Uniform Fertilizer Tests of the Cooperative
Research In Forest Fertilization Program .................................. 6

R results and D discussion ............................................. ................. 6

A. Rust Incidence in Forest Industry
Plantation Inventory Plots ............................... ..................... 6

1. County Sum m ary ...................................... .................. 6
2. G geographic D distribution ............................... .................... 8
a. County averages............................. .................. 8
b. Discrete areas of rust incidence................... .................. 9
c. Longitude and latitude................... ................... 10
3. Age and Year of Planting ................. ................................ 13

B. Rust Incidence in Progeny Tests of the
Cooperative Forest Genetics Research
P program ........................................................... .................. 14

C. Rust Incidence in Uniform Fertilizer Tests of
the Cooperative Research In Forest Fertilization
P program ............................... ..... .............. .................. 17

D. Comparison of Rust Incidence in Industry,
Forest Genetics, and CRIFF Plantations ................................. 17

C conclusions ................... ..................... ......................... 19

Literature C ited .................................... ....... .......................... 20

A cknow ledgm ents ................................................ ........................ 2 1








Summary
Analyses of 1,286 forest industry slash pine plantations show that
the average rust incidence in the counties surveyed is 31.1%; the
average is 20.6% and 38.3% for Florida and Georgia, respectively.
County averages range from less than 10% to more than 50% in
Florida and less than 10% to more than 70% in Georgia. Individual
plantations range from 0 to 95.1% in Florida and 0 to 100% in
Georgia. Ten counties, two in Florida and eight in Georgia, have
average rust of more than 50%.
Rust increases from southeast to northwest and from the coast to
inland, as indicated by the county averages and by discrete areas of rust
incidence which disregard county boundaries. Several adjacent areas
have groups of plantations with a dissimilar incidence of disease, which
suggests a site-rust interaction, especially with regard to a coastal
influence. Quantification of the geographic distribution of rust by
regression analyses reveals a direct relationship with latitude and
longitude. This empirical relationship is particularly evident in Florida
where contiguous data are available. Predicted percent rust, based on
a regression equation using latitude and longitude, is given for that
area of Florida encompassed in the data set.
The age of the plantation and the year of planting is associated
with percent rust. Predicted percent rust, based on a regression equation
using age and year of planting, indicates that among plantations
established from 1950-65 rust increases to a maximum between ages
ten and eleven and thereafter declines. Among plantations established
from 1950-65 rust is increasing with each succeeding year at a rate of
2-3% per year. Among plantations established in the same year,
maximum rust has occurred in those planted in 1954 and before; rust
continues to increase in those plantations established since 1954 and
the rate of increase is quite high in newly established plantations.
In 59 progeny tests the average rust is 21.5% and 30.5% for three
and five-year-old plantations, respectively. Analyses of 31 fertilizer tests
indicate average rust values of 8.0%, 27.1%, and 35.7% for two, three,
and five-year-old plantations, respectively. Although the fertilizer and
progeny tests have higher rust incidence than the industry plantations,
the differences are not great when the data are adjusted for year of
planting.
Distribution of rust incidence for the progeny and fertilizer tests is
similar to that for the industry plantations, although some differences
are evident.








Introduction
Fusiform rust, the most important disease of slash pine (Pinus
elliottii Engelm. var. elliottii) in Florida and Georgia, causes an
estimated annual loss of 97 million cubic feet of growing stock or 281
million board feet of saw timber in southern pine (6)'. These outdated
and, therein, conservative estimates, represent an annual stumpage loss
of $10 million (16) or $250 million in finished wood products (based on
a 25-fold increase in stumpage values). Accurate estimates of the impact
of fusiform rust in slash pine are not available and can not be obtained
until the incidence and distribution of the disease are well characterized.
Fusiform rust is caused by the fungus Cronartium fusiforme
Hedge. & Hunt ex Cumm. The life cycle of this obligate parasite is
typical of many rust fungi; i.e., it is heteroecious (requires two hosts)
and macrocyclic (produces five spore types). Pycnial and aecial spore
stages occur on the pine host and uredial, telial, and basidiospore stages
on oak. Water oak (Quercus nigra L.) appears to be the most important
host oak in Florida, although there are other susceptible species.
Infection of pine occurs in the spring as wind-disseminated
basidiospores produced on telial columns on oak leaves colonize
succulent shoots and primary needle tissues of pine. Subsequently, the
fungus grows into branch and stem tissues where a gall is formed
(Figure 1). Stem galls result in tree mortality, as young trees are killed
and older trees are subject to wind breakage (Figure 2). In the latter
case, severely diseased stands must be salvaged prior to optimum
harvest age. Foliar fungicides protect nursery seedlings (3), but at
present there is no feasible control for plantations or natural stands.
Development of rust-resistant pines is receiving considerable attention
(5, 14, and 17), and appears to provide hope for disease control in
plantations.
The rust incidence data reported here were gathered from the
forest industry and cooperative projects at the University of Florida for
the following purposes: (i) to identify high hazard rust areas for select
tree progeny test sites, (ii) to identify high hazard areas where rust free
selections could be made, (iii) to identify high hazard areas to efficiently
utilize improved rust-resistant seedlings, and (iv) to provide a set of
data to investigate the influence of site and environmental factors on
the development of fusiform rust. The first three of these objectives
have been realized. The last, i.e., the effects of independent variables
such as edaphic, climatic, or biotic environmental factors on the
incidence of rust, can only be accomplished once the occurrence and
distribution of the rust has been defined.
Therefore, it is the object of this work to define the rust distribution,
insofar as the data will allow, and to begin to analyze this distribution

'Numbers in parentheses refer to Literature Cited.

2
































Figure 1. Fusiform rust branch and stem galls on pine caused by Cronartium fusiforme.

in terms of the effects of independent variables. These preliminary
analyses include only the empirical relationships with geographic
location and age parameters. Analyses of cause and effect relationships
will constitute the next phase of research (7).

Data Source
A. Forest Industry Plantation Inventory Plots

1. Container Corporation of America (CCA). These data, taken
from 1,084 plantations in conjunction with forest inventory, provide
most of the observations for the forest industry plantation plots. The
inventory was conducted in 1966-69 in plantations established in
1948-65 (1). The number of 1/50 acre sample plots used to calculate
percent disease increased with plantation size, e.g., 6 to 10 acres = 27
plots; 551 to 600 acres = 144 plots. Percent disease represents the
number of trees with a branch or stem gall relative to the number of
trees on the sample plot.
2. Buckeye Cellulose Corporation (BCC). These data were
taken in conjunction with an insect and disease survey and growth
study and include 202 plantations. One set of 62 plantations, planted in
1953-62, was sampled in 1966-67 (11). A second set of 140 plantations,
established in 1956, 1957, and 1959 was examined at age ten (15). In

3















Vi


































Figure 2. Severely damaged slash pine plantation in which many diseased trees have
been broken over at fusiform stem galls.

either case, a sample consists of one 1/10 acre plot per plantation and
percent disease represents the number of diseased trees in relation to
the number of trees on the sample plot with the exception that trees
having branch galls more than 12 inches from the stem were not
counted as diseased in the latter set of 140 plantations.

4










As the CCA and BCC data are similar with regard to methods of
percent rust estimation, they are combined for analysis. Figures 3 and 4
show the frequency distribution of the 1,286 plantations with regard to
age and year of planting.




220

200

180-

z 160-
0
S140-
z
S120

100-

s 80

60

40-



4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21
PLANTATION AGE (YEARS)

Figure 3. Frequency distribution by age for 1,286 slash pine plantations.




220 -

200 -

180 -

z 160-
0
140

- 120-
. -
0100-

80 I-

60

40-


:- --] -______^__ _
1964 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48
YEAR OF ESTABLISHMENT

Figure 4. Frequency distribution by year of establishment for 1,286 slash pine
plantations.


5








B. Progeny Tests of the Cooperative Forest Genetics Research
Program
These data from 59 field progeny tests located in Florida, Georgia,
Alabama, and Mississippi were taken by the Cooperative Forest
Genetics Research Program. Progeny tests were established in 1963-69
and the data represent third and fifth-year measurements. Tests vary in
numbers of families (half or full-sib progeny) from 7 to 89. Families are
arranged in 7 to 10 tree row-plots in each of 4 to 10 blocks. Percent
disease is calculated as the number of diseased trees in relation to the
number of trees in the test and represents a 100% sample. Variation
among progeny with respect to rust resistance is not considered in this
analysis.
C. Uniform Fertilizer Tests of the Cooperative Research in Forest
Fertilization Program
These data were obtained from 31 uniform field fertilizer tests
located in Florida and Georgia and were collected by the Cooperative
Research in Forest Fertilization Program (CRIFF) at the University of
Florida. Tests were established in 1967-69 and the rust data were taken
at ages two, three and five. Each observation represents a 100% sample
of 2,160 trees arranged as 3 blocks of 12 treatments with 60 trees per
treatment. Percent rust is probably a conservative estimate, as it is
based on the number of living trees, i.e., trees dead of rust are not
included as diseased. The effect of fertilizer treatment on rust incidence
is not considered in this analysis.

Results and Discussion
A. Rust Incidence in Forest Industry Plantation Inventory Plots
1. County Summary. Table I provides a summary by county of the
percent trees with rust in slash pine plantations in Florida and Georgia.
The average age for the 1,286 plantations is 10 years. In Florida, the
average rust per county in the 15 counties is 20.6%, and the county
averages range from 3.1% to 56.7% diseased. Individual plantations
range from 0 to 95.1% diseased. In Georgia, the average rust per
county in the 22 counties is 38.3% and the county averages range
from 5.1% to 71.0%. Individual plantations range from 0 to 100%
diseased. The county average for both states combined is 31.1%. In
ten counties, two in Florida and eight in Georgia, the average amount
of fusiform rust is more than 50%. While there is substantial variation
in these data as characterized by the standard deviation and the
deviation of the mean, and some counties with relatively few ob-
servations are ill-defined, the incidence of rust in others is
better defined, especially in Alachua, Bradford, Madison, Nassau,
and Taylor counties in Florida, and Laurens and Telfair counties
in Georgia. Less confidence is placed in the county averages for

6









Table 1. County summary of the incidence of fusiform rust in slash pine plantations in
Florida and Georgia.

Plantations Percent Trees With Rust
Standard
Average Standard Deviation
County Number Age Range Average Deviation of the Mean


Florida
Alachua 135 11.2 0-29.2 10.6 6.02 0.52
Bradford 109 7.9 0-37.2 5.9 7.10 0.68
Columbia 6 7.2 3.9-43.8 28.6 14.83 6.06
Dixie 11 11.6 7.1-29.6 16.9 7.74 2.33
Duval 30 8.8 0-26.9 11.5 6.84 1.25
Gilchrist 16 10.9 0.9-15.1 6.3 4.68 1.17
Jefferson 8 9.6 44.3-67.9 54.7 9.29 3.29
Lafayette 7 10.1 6.7-34.6 18.6 9.96 3.77
Levy 9 9.3 0- 6.6 3.1 2.26 0.75
Madison 94 10.0 0-95.1 56.7 18.48 1.91
Marion 27 8.7 0-35.2 9.9 9.20 1.77
Nassau 201 10.3 0-57.7 17.3 12.39 0.87
St. Johns 8 9.0 0-15.1 7.8 4.21 1.49
Suwannee 8 9.1 6.0-73.4 29.7 20.28 7.17
Taylor 185 10.3 1.5-79.5 31.6 17.75 1.30
S854 Ave. 9.6 20.6

Georgia
Atkinson 5 8.2 13.4-67.8 37.5 23.25 10.40
Bacon 16 11.8 0-22.6 8.2 6.90 1.70
Brantley 7 10.7 4.8-29.7 15.0 10.00 3.76
Charlton 22 8.0 0-28.2 9.2 6.31 1.35
Clinch 36 7.2 0-25.6 7.2 7.70 1.28
Chattahoochee 7 11.3 36.6-66.7 50.2 9.43 3.57
Dodge 18 12.5 11.1-54.9 37.6 12.34 2.91
Echols 6 11.0 13.6-59.5 33.6 15.00 6.12
Lanier 3 10.7 30.1-51.6 42.3 11.03 6.37
Laurens 109 9.6 0-74.1 39.1 16.52 1.58
Macon 10 11.5 35.1-76.9 61.6 14.41 4.56
Marion 8 10.8 32.4-91.9 67.2 16.66 5.89
Pierce 3 5.6 0-15.4 5.1 8.89 5.13
Randolph 14 11.9 43.6-80.0 65.3 9.67 2.59
Schley 3 12.0 58.4-71.4 62.8 7.45 4.30
Stewart 12 11.2 54.5-100 70.0 13.99 4.04
Telfair 92 9.3 0-79.5 29.9 14.79 1.54
Terrell 3 15.0 15.6-42.2 27.1 13.66 7.89
Ware 31 7.3 0-67.7 22.5 14.42 2.60
Wayne 4 11.3 8.8-41.6 26.7 13.57 6.79
Webster 4 9.5 66.7-77.5 71.0 5.27 2.63
Wheeler 19 10.2 25.4-77.8 52.6 15.14 3.47
1432 Ave. 10.3 38.3

2 1286 !Ave. 10.0 31.1



7









Georgia because of the small number of plantations sampled in
some counties.
2. Geographic Distribution.
a. County averages. The geographic distribution of percent rust
based on county averages (Figure 5) indicates that rust increases from
southeast to northwest and from the coast to inland. In Florida, where a
contiguous set of data exists, rust increases from 0-15% in the south
and along the east coast to 46-60% in the northwest. In Georgia, the
same trend is evident; rust increases from 0-30% in the southeast and
along the coast to a high of 61-75% in the north and west. More
variation between adjacent counties is evident in Georgia because the
averages are based on relatively few samples in some counties. In both
states rust estimates in some counties with few samples are
substantiated by estimates in adjacent counties having larger numbers
of samples.




T o11P w- L








Per Cent Rust



" ..... 31 -45 U3















Figure 5. Incidence of fusiform rust based on county averages for slash pine plantations
in Florida and Georgia.

8








b. Discrete areas of rust incidence. Disregarding county boundar-
ies, groups of adjacent samples were pooled and summarized. The
number of plantations and average percent rust are given in Table 2,
and the approximate location of the 29 areas is shown in Figures 6.
Differences in percent rust among areas were not tested statistically.
Again, percent rust increases from southeast to northwest and
from the coast to inland. In Florida, several counties with large numbers
of samples, e.g., Nassau and Taylor counties, have within their
boundaries groups of plantations with seemingly different amounts of
rust. This preliminary analysis suggests that site conditions might
affect the incidence of fusiform rust.
The incidence and distribution of rust given herein are similar to
those recently reported for Florida (12) and Georgia (13), but differ by
having a higher incidence and a dissimilar distribution from those
reported in 1937 (8).














^\ 1Per ent Rust

.-ER a 15 0
17- ^ 10-30
F re 6. fr i atar e



WAKU00 0 8
based on the averages of adjacr ent (approximate


04 o- s ( oi m
Or-- 16 -3 C O 7

0ased ton 0te a ( r t



















9









Table 2. Average incidence of fusiform rust for discrete geographic areas irrespective of
county boundaries.
Area Numbera Number of Plantations Average % Rust

1 20 2.0
2 12 17.8
3 54 10.9
4 10 4.2
5 91 11.1
6 11 6.6
7 31 2.2
8 13 8.8
9 8 9.3
10 69 20.8
11 19 33.4
12 11 11.0
13 5 20.6
14 4 34.8
15 136 11.6
16 85 21.8
17 25 36.2
18 6 29.2
19 24 29.3
20 48 34.5
21 102 58.5
22 54 6.8
23 54 20.4
24 92 29.1
25 94 40.8
26 3 27.1
27 13 58.2
28 37 68.9
29 7 50.2
S1148b

a Area numbers agree with those in Figure 6.
b Isolated plantations were not included in these averages for discrete areas.





c. Longitude and latitude. Quantification of the apparent relation-
ship (Figures 5 and 6) between the percentage of rust and geographic
location is examined by regression analyses. These analyses use the
variables longitude and latitude as indices of location for each
plantation and percent rust as the dependent variable. Table 3 gives
the regression equations and percent of rust variability accounted for by
the independent variables. These analyses indicate that 50.1%, 54.8%,
and 8.6% of the rust variability is associated with longitude and latitude
in Florida and Georgia combined (Eq. 1), Florida (Eq. 2), and Georgia
(Eq. 3), respectively. Inspection of these equations reveal again the
increase of rust along a vector running southeast to northwest.


10








Because rust incidence is a highly variable character which is
confounded with seed source (4), site preparation (2 and 10), and other
site factors and interactions, not accounted for in these analyses, that
amount of rust variability accounted for by longitude and latitude is
quite significant, especially for Florida. The relationship of latitude and
longitude with rust incidence is not nearly so good for the Georgia
data and reflects, no doubt, the relatively small number of samples.
Nevertheless, when combined with that for Florida, a very significant
amount of rust variation is accounted for. Within Florida, more rust
variability might have been explained if the coastal influence was
taken into consideration. A recent report from Texas (9) indicates that
rust is most severe in the southeast portion of the state and suggests
the higher precipitation average and coastal humidity might be
contributing factors. This higher incidence near the coast is contrary to
the results presented here.
Using the significant relationship between rust and geographic
location in Florida, the amount of rust is predicted by the regression
equation (Eq. 2) for that area included within the data set (Figure 7).
While this equation and the others in Table 3 are not meant to be used
as predictive models, due to their preliminary nature, they do quantify
the geographic distribution and provide a useful tool for analyses of
cause and effect relationships between environmental factors and rust
incidence.

840 830 82 810


50 45 40 36 31 2 22 17 13
U
45 40 36 31 27 22 17 13 8 4
300 40 36 31 26 22 17 13 30"

31 26 22 17 13 8
17 12 8 3

8 3
290 3 290






84 830 820 810

Figure 7. Predicted percent rust based on the regression equation using latitude and
longitude for Florida. (Eq. #2, Table #3.)

11













Table 3. Independent variables, regression equations, and percent of fusiform rust variability associated with independent variables for slash
pine plantations.

% Rust Variability
Equation Independent Associated with Number of
Number Variables Regression Equation Independent Variables Plantations
1 Longitude and lati- %Rust = 54.4396-2.8477(Lon)
tude; Florida and -45.0556(Lat)+0.6259(Lon) (Lat) 50.1** 1,286
Georgia

2 Longitude and lati- %Rust =-2065.42+18.4173(Lon)
tude; Florida +18.7739(Lat) 54.8** 854

3 Longitude and lati- %Rust =2.9733-4.2444(Lon)
tude; Georgia +12.0648(Lat) 8.6** 432

4 Age of tree and year %Rust =-29.2902+7.6823(Age)
planted; Florida and -0.5898(Year-1950)-0.3053(Age)2 9.8** 1,286
Georgia +0.0992(Year-1950)2+0.1868(Year-
1950) (Age)

a Year of planting is indexed as (Year planted- 1950)
b Statistical significance: ** = 1%








3. Age and Year of Planting. Regression analysis is used to examine
the relationship between percent rust and the independent variables,
age and year of planting, irrespective of geographic location. Equation 4
(Table 3), indicates for the combined Florida and Georgia data that
9.8% of the variation in percent rust is associated with age and year of
planting. While this was a significant amount of rust variability
accounted for, perhaps because of the large number of plantations,
addition of age and year of planting to the regression equation for
latitude and longitude (Eq. 1) only increased the rust variability
accounted for from 50.1% to 54.0%.
Figure 8 shows the predicted percent rust as a function of age and
year of planting based on Equation 4. Several important conclusions
are suggested from this analysis.
Among plantations established from 1950-65, rust increases to a
maximum at age ten to eleven and declines thereafter. This decline in
percentage of trees with galls can be ascribed to several factors:
(i) mortality of stem-galled trees, (ii) natural pruning of limb galls,




4 0 I--III I I I I I I I I1

60 59 58
57
56

55
30 63

i 64 57// 5 4 \
-58
r 25 53

52
S1969 60
20-
1968 52

15 1967 / 50

1966 62 51

10 50

O II i l l l il l l i l l
4 5 6 7 8 9 10 II 12 13 14 15 16 17 18
PLANTATION AGE (YEARS)
Figure 8. Percent rust estimated as a function of plantation age and year of
establishment. The numbers to the left of the curves are the years the data
were taken while those above and below the curves identify the years the
plantations were established.



13








(iii) new infections in older plantations have a greater probability of
occurring on previously diseased trees; and (iv) the older plantations
were established when rust was not so severe as for plantations
established later. These data do not indicate that older plantations in
the future, will have low percentages of rust; in fact, the reverse will
presently be shown to be the case. Nor do they indicate that older trees
are less susceptible to Cronartium fusiforme.
Among plantations established from 1950-65 rust increases 2-3%
with each succeeding year. For example, the estimated rust for ten-year
old plantations established in 1956, '57, '58, and '59 is 28.2%, 30.8%,
33.6%, and 36.5%, respectively. This is an average increase of 2.8%
per year for all plantations and is foreboding; but more alarming is the
high rate of increase occurring in the high incidence rust areas.
Among plantations established in the same year percent rust has
reached a maximum and is declining in those stands planted in 1954
and previously. The rational for this decline is discussed above. In
plantations established after 1954 the amount of rust is increasing and
at an alarming rate for those established recently. In a report of rust
incidence in Texas (9) no relationship between "degree of infection"
and tree age class was evident.
No conclusions can be made regarding "rust years" (years when
rust is severe) as these data represent accumulated rust throughout the
life of the plantation. The year in which the infection occurred is not
known.


B. Rust Incidence in Progeny Tests of the Cooperative Research in
Forest Genetics Program.
The incidence of fusiform rust in 59 progeny tests is shown in
Table 4. The average rust for three-year-old plantings is 21.5% and tests
range from 2.0% to 60.6% diseased. Average rust for the fifth-year
measurements of the same plantations is 30.5% and tests range from
2.4% to 69.7% diseased. The average increase for 19 of the tests with
appropriate measurements is 14.9% for the two-year period. The
minimum increase was 0.8% while the maximum increase was 40.6%.
Geographic distribution of percent rust from 40 progeny tests,
either fifth-year or reliable third-year measurements (tests adequately
exposed to rust) is shown in Figure 9. Rust distribution tends toward
that of the industry plantations in that percent rust is low in the
southeast of Florida and increases toward the north and west. An
increase along the southeast to northwest vector is not as evident in
these data nor is the suggested coastal influence as definitive as for the
industry plantation data. As was the case with the industry data, Taylor
and Nassau counties, Florida, and Wayne County, Georgia, show
considerable variation in percent rust within their boundaries.

14









Per Cent Rust

0-15 0
16-30
31-45 *
46 -10
61-75 X


[ Fertilizer trials
0 Progeny tests















Figure 9. The location (approximate) and incidence of fusiform rust in slash pine
progeny tests and fertilizer trials.

40- 40


S 3 0 73 0 '



I. 10 10 -
n20 20




A B
I I I I I I I I I I
2 3 4 5 61 62 63 64 65 66 67 68
PLANTATION AGE (YRS.) YEAR PLANTED
Figure 10. Average percent fusiform rust in slash pine plantations in Florida and Georgia.
A. Actual (.- .) and projected (.---.) percent rust as a function of age of
plantation: (a) CRIFF fertilizer tests, (b) industry plantation data projected
for the mean year of planting (1968) of the CRIFF plantations, (c) progeny
test plantations, (d) industry plantation data projected for the mean year of
planting (1966) of the progeny tests, and (e) industry plantation data.
B. Estimated (. .) and projected (.---.) percent rust for industry
plantations as a function of age of the plantation and the year of planting.

15









Table 4. Incidence of fusiform rust on slash pine in progeny tests of the Cooperative
Forest Genetics Program.
Average % Rust

Progeny Test Number of 3rd 5th
Number Families Year Year Increase

0-3 18 -11.1
1-3 7 41.6
1-4 7 28.6
1-5 12 41.8
1-6 35 33.8
1-7 33 22.3
1-8 56 16.5
1-9 56 18.7
1-10 58 28.5
1-11 57 18.7
1-12 46 28.6 53.6 25.0
1-13 46 26.0 54.5 28.5
1-14 25 30.2
1-15 18 52.5
1-16 17 12.2
1-17 17 2.5
1-21 44 13.6
1-22 44 4.1
2-1 23 6.1 13.9 7.8
2-2 22 12.9 13.7 0.8
2-3 19 3.7 11.4 7.7
2-4 13 57.5
2-5 22 22.2
3-2 9 40.5
3-3 11 9.6
3-4 16 6.1
3-5 10 29.1 45.4 16.3
3-6 9 15.5
3-7 39 21.8 37.4 15.6
3-8 27 12.3
3-9 11 12.8
3-10 47 14.6
4-3 28 54.8 69.7 14.9
4-4 19 50.4 67.5 17.1
4-5 12 49.0 69.2 20.2
4-6 54 12.3
4-7 29 30.5
6-4 47 8.6
6-6 33 7.3
6-7 49 8.2 25.3 17.1
6-8 47 9.3 22.1 12.8
6-10 19 14.6 23.0 8.4
6-12 10 7.7 26.2 18.5
6-14 12 2.0
6-15 15 5.3
6-16 10 12.8




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Table 4 (Continued). Incidence of fusiform rust on slash pine in progeny tests of the
Cooperative Forest Genetics Program.
Average % Rust
Progeny Test Number of 3rd 5th
Number Families Year Year Increase
7-6 15 13.0 53.6 40.6
7-7 16 48.0 52.0 4.0
7-8 21 35.6 41.7 6.1
7-9 21 34.3 54.3 20.0
7-10 41 52.2
7-11 21 29.3
7-13 44 19.9
8-3 34 8.8
8-4 26 60.6
11-1 21 2.9 2.4 -0.5a
11-2 89 4.5 5.3 0.8
11-3 20 5.5
11-5 20 4.6
S 59 21.5 30.5 14.9
a Negative value excluded from calculation of average increase.




C. Rust Incidence in Uniform Fertilizer Tests of the Cooperative
Research In Forest Fertilization Program.

The incidence of fusiform rust in 31 fertilizer tests is shown
in Table 5. The average rust for two, three and five-year-old plantations
is 8.0%, 27.1% and 35.7%, respectively. The ranges in percent rust are
0 to 44.8, 0.3 to 68.5, and 2.0 to 80.6. The average increase for 25 tests
for the three year period is 27.5%. The maximum increase is 66.0% and
the minimum increase is 0.2%.
The geographic distribution of percent rust from 24 of the tests
with reliable measurements (excluding those with low rust which also
had poor survival) is shown in Figure 9. The distribution of rust is
similar to that for the industry plantations. In Florida, rust increases
from southeast to north and west and some indications of a coastal
influence exist. In Georgia, a coastal influence is not evident and rust
increases toward the north.


D. Comparison of Rust Incidence in Industry, Forest Genetics, and
CRIFF Plantations.

In comparing the amount of rust among the data sets, it first
appears that there is substantially more rust in the fertilizer and progeny
tests than in the industry plantations (Figure 10 lines a, c, and e).
However, if the earlier conclusion, that rust is increasing with each
succeeding year, is correct, the three data sets are not strictly

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Table 5. Incidence of fusiform rust in slash pine plantations in CRIFFa fertilizer tests in
Florida and Georgia.

Average % of Rustb

% Tree
Test Survival Age 2 Age 3 Age 5 Increase
Number 1970 1969 1970 1972 Age 2-5

1 95 4.0 18.4 17.4 13.4
2 80 20.7 61.7 65.3 44.6
3 82 9.2 57.5 48.3
4 79 11.1 44.9 33.8
5 92 0.6 29.8 37.3 36.7
6 98 14.7 65.0 65.0 50.3
7 99 0.1 1.8 4.1 4.0
8 91 9.2 28.4 52.5 43.3
10 67 3.0 11.8 21.8 18.8
11 75 32.2 48.9
12 60 5.3 38.9
13 40 2.3 20.4
15 90 1.4 1.6 2.9 1.5
16 83 2.9 0.3 3.1 0.2
17 61 0.0 1.6 2.0 2.0
18 95 0.1 10.3 25.4 25.3
19 75 0.1 3.9 15.8 15.7
20 57 0.3 5.8 10.2 9.9
21 94 0.1 1.9 15.9 15.8
22 96 44.8 58.0 57.8 13.0
23 77 3.7 9.3 15.7 12.0
24 63 2.5 21.6 31.7 29.2
25 65 14.6 29.2 80.6 66.0
26 72 19.7 68.4 68.4 48.3
27 56 4.5 56.2 58.9 54.4
28 63 2.1 57.9 59.3 57.2
29 82 1.3 14.8 17.2 15.9
30 98 34.8 68.5 61.5 26.7
31 87 0.2c 1.8d
35 96 0.8c 16.5d
36 46 1.5 32.7d -
S31 Ave. 8.0 27.1 35.7 27.5

a Cooperative Research in Forest Fertilization.
"b Percent of living trees, i.e., trees dead of rust not included.
c Age one year.
d Age two years.



comparable since the trees were planted in different years. If the data
are adjusted for year of planting by projecting the estimated trends in
Figure 8, the differences are not great, especially for the five-year-old
trees. For example, the projected values for three and five-year-old
plantations established in 1966 (the average year of planting for the
progeny tests) are 16.5% and 30.5% (Figure 10, line b) as compared with


18








21.5% and 30.5% obtained in Table 4. Similarly, the projected values for
three and five-year-old plantations established in 1968 (the average
year of planting for the CRIFF fertilizer tests) are 21.5% and 36.5%
(Figure 10, line d) as compared with 27.1% and 35.7% obtained in
Table 5. The difference between the progeny test averages and those for
the fertilizer tests can be rationalized in the same manner, i.e., due to
the effects of year of planting.

Conclusions
The objective of these preliminary analyses was to quantify the
incidence and distribution of fusiform rust in slash pine plantations
from existing data. Because the percent of trees diseased was based on
the number of trees infected regardless of whether this infection was an
economically unimportant branch gall or a lethal stem gall, no
specific mortality or impact estimates can be assigned to these
percentages. For example, a plantation with a large number of diseased
trees might have a smaller number of trees with stem galls and of
these only a few with lethal stem galls.
With these points in mind the important conclusions are:
1. Fusiform rust is a serious threat to slash pine plantations in Florida
and Georgia. County averages reveal that 31.1% of the trees are
diseased and more than one fourth of the counties sampled had
greater than 50% of the trees diseased.
2. Among the industry plantations there are indications of site-rust
interactions as adjacent areas sometimes had dissimilar amounts of
rust. Similarly, there appeared to be less rust along the coast than
farther inland.
3. In forest industry plantations the percent rust increases from
southeast to northwest. This relationship is especially evident in
Florida where 54.89( of the variation in rust incidence is associated
with latitude and longitude.
4. Among plantations established throughout the period of the study
rust increases to a maximum at age ten to eleven and thereafter
declines.
5. Among plantations established throughout the period of the study
rust increases 2-3% with each succeeding year and does not reach
a maximum within the data; i.e., rust is continuing to increase
with each year.
6. Among plantations established in the same year, maximum rust
has been reached and is declining in those planted in 1954 and
before. Rust continues to increase in stands planted since 1954 and
at an alarmingly high rate in young stands.
7. The incidence of rust is higher in the fertilizer and progeny tests
than in the industry plantations. However, this difference is not
great if the data are adjusted for year of planting.

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8. The distribution of rust among the three data sets is similar
although with fewer samples the progeny and fertilizer tests show
less definitive trends.
9. These three data sets provide insight as to the occurrence and
distribution of fusiform rust as related to site and environmental
factors and therein pave the way for meaningful quantification of
the relationship.




Literature Cited


1. Anonymous. 1966. Field instructions for plantation inventory. Container Corporation
of America. Mimeo. 9 p.

2. Dinus, R. J., and R. C. Schmidtling. 1971. Fusiform rust in loblolly and slash pines
after cultivation and fertilization. USDA Forest Service. Res. Paper SO-68. 10 p.

3. Foster, A. A., and D. W. Krueger. 1961. Protection of pine seed orchards and nurseries
from fusiform rust by timing ferbam sprays to coincide with infection periods.
Ga. Forest Res. Counc. Res. Paper 1. 4 p.

4. Gansel, C. R. 1970. Racial variation in slash pine and association with environmental
factors. Establishment and progress report. Study G-49. USDA Forest Service.
Olustee, Florida. 14 p.

5. Goddard, R. E., and R. A. Schmidt. 1971. Early identification of fusiform rust
resistant slash pine families through controlled inoculation. In: Eleventh South.
Forest Tree Impr. Conf. Proc. p.31-36.

6. Hepting, G. H., and G. M. Jemison. 1958. Forest protection. In: Timber Resources for
America's Future. USDA. Forest Service, Forest Res. Rept. No. 14. p. 184-220.

7. Hollis, C. A., and R. A. Schmidt. 1972. Influence of site and environmental factors on
the incidence of fusiform rust on slash pine A study plan. Coop. Agree. 19-120.
Univ. of Florida and South. Forest Expt. Sta., Gulfport, Miss. 19 p.

8. Lamb, H., and B. Sleeth. 1937. Distribution and suggested control measures for the
southern pine fusiform rust. USDA Forest Service, South. Forest Expt. Sta.,
Occasional Paper No. 72. 5 p.

9. Mason, G. N., and J. K. Griffen. 1970. Evaluating the severity of fusiform rust in East
Texas pine plantations. Forest Farmer 29: 8-9.

10. Miller, T. 1972. Fusiform rust in planted slash pines: influence of site preparation and
spacing. Forest Sci. 18: 70-75.

11. Morris, J. E., and J. R. Mims. 1968. Incidence of fusiform rust in plantations and its
effect on yields. Progress Report. Project XXV: Insects and diseases. Buckeye
Cellulose Corp. Mimeo. 14 p.

12. Roth, E. R., and C. W. Chellman. 1971. Florida fusiform rust survey 1971. USDA
Forest Service, Southeastern Area and Florida Division of Forestry.

13. Roth, E. R., and W. H. McComb. 1971. Georgia fusiform rust survey 1971. USDA
Forest Service, Southeastern Area and Georgia Forestry Commission.

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14. Schmidt, R. A., and R. E. Goddard, 1971. Preliminary results of fusiform rust
resistance from field progeny tests of selected slash pines. In: Eleventh South.
Forest Tree Impr. Conf. Proc. p. 37-44.

15. Stephenson, W. L. 1969. Growth studies. Project outline, Project VII. Buckeye
Cellulose Corp. Mimeo. 6 p.

16. Verall, A. F., and F. J. Czabator. 1970. Fusiform rust of southern pines. USDA Forest
Service, Forest Pest Leaflet 26. 6 p.

17. Zobel, B., R. Blair, and M. Zoerb. 1971. Using research data disease resistance.
J. Forest. 69: 486-489.




Acknowledgments

The authors gratefully acknowledge the contributions of R. W. Gowen and
L. Draper, Jr. of Container Corporation of America, Fernandina Beach, Florida, and
J. E. Morris and W. L. Beers of Buckeye Cellulose Corporation, Perry, Florida, for
providing the forest plantation inventory data; industry cooperators in the Cooperative
Forest Genetics Research Program for providing the progeny test data; W. L. Pritchett,
W. H. Smith and industry cooperators in the Cooperative Research In Forest Fertilization
Program for providing the fertilizer test data; M. A. Hryshkanyck, R. J. Gilmore and
R. H. Zerba for compiling the data; and F. G. Martin for the regression analyses. This
project was supported by McIntyre-Stennis funds; Cooperative Agreement #19-120 from
the United States Forest Service, Southern Forest Experiment Station, Gulfport,
Mississippi; and by the Special Help for Agricultural Research (SHARE), Institute of
Food and Agricultural Sciences, University of Florida, Gainesville.
































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This public document was promulgated at an annual cost of
$1,081.31 or a cost of 360 per copy to provide a summary of data
on the incidence and distribution of fusiform rust.





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