• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Table of Contents
 Development of the fusiform rust...
 Losses to fusiform rust
 Biology of the fusiform rust pathosystem...
 Ecology of the fusiform rust pathosystem...
 Management of fusiform rust to...
 Benefits of research
 Summary
 Reference
 Acknowledgement






Group Title: Bulletin (Tech.) - Agricultural Experiment Station, University of Florida - 903
Title: Fusiform rust disease of southern pines
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
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Permanent Link: http://ufdc.ufl.edu/UF00027265/00001
 Material Information
Title: Fusiform rust disease of southern pines biology, ecology and management
Series Title: Bulletin (Tech.)
Physical Description: 14 p. : ill., maps ; 28 cm.
Language: English
Creator: Schmidt, Robert A
University of Florida -- Agricultural Experiment Station
Publisher: University of Florida, Agricultural Experiment Station, Institute of Food and Agricultural Sciences
Place of Publication: Gainesville FL
Publication Date: <1998>
 Subjects
Subject: Pine fusiform rust -- Southern States   ( lcsh )
Pine -- Diseases and pests -- Southern States   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 13-14).
Statement of Responsibility: Robert A. Schmidt.
General Note: Cover title.
General Note: "March 1998."
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
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Bibliographic ID: UF00027265
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
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Table of Contents
    Copyright
        Copyright
    Front Cover
        Front Cover 1
        Front Cover 2
    Table of Contents
        Page 1
    Development of the fusiform rust epidemic
        Page 1
        Page 2
    Losses to fusiform rust
        Page 3
    Biology of the fusiform rust pathosystem - a complex life-style
        Page 4
        Page 5
    Ecology of the fusiform rust pathosystem - a rust favorable environment
        Page 6
    Management of fusiform rust to reduce losses
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Benefits of research
        Page 12
    Summary
        Page 12
    Reference
        Page 13
    Acknowledgement
        Page 14
        Page 15
Full Text





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
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the Institute and its staff. Current IFAS
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(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




/loo0

S93
March 1998


Bulletin (Tech.) 903


Fusiform Rust Disease of Southern Pines:
Biology, Ecology and Management


Robert A. Schmidt


UNIVERSITY OF
FLORIDA
Agricultural Experiment Station
Institute of Food and Agricultural Sciences















r6 3 bL.
U ., /*














































Robert A. Schmidt is a professor, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of
Florida, Gainesville, FL 32611.

The use of specific trade names in this publication does not constitute endorsement of these products in preference to others
containing the same active ingredients. Mention of a proprietary product does not constitute a guarantee or warranty of the product by
the authors or the publisher.
All chemicals should be used in accordance with directions on the manufacturer's label.








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


Contents

Development of the Fusiform Rust Epidemic ....... 1
Losses to Fusiform Rust ........................... 3
Biology of the Fusiform Rust Pathosystem A
Complex Life-style .......................... 4
Life History .................... ...... 4
Susceptible Species ...................... 5
Pines ... .......................... 5
Oaks ... .......................... 5
Ecology of the Fusiform Rust Pathosystem A Rust
Favorable Environment ....................... 6
Natural Old Growth Forests Contrasted with
Intensively Managed Plantations .......... 6
Critical Factors .................... .6
Pine Regeneration and Growth .......... 6
Susceptible Oaks .................. .. 6
Soils ..... ......... ............. 6
Climate ............................ 7
Improved Planting Stock ............... 7
Management of Fusiform Rust to Reduce Losses .... 7
Evaluating Rust Hazard Risk ............... 7
Reducing Losses in Moderate- and High-
Hazard Areas ....................... 9
Site Preparation .................. ... 9
Rust-resistant Planting Stock ........... 9
Plant Healthy Seedlings .............. 10
Oak Management ................... 10
Delay Fertilization ................... 10
Alternative Species and Silviculture ..... 10
Preventing Rust in Low-Hazard Areas ...... 11
Nursery Planting Stock ............... 11
Encroachment of Oak ................ 11
Treating Infected Stands ................. 11
Replant ........................... 11
Prune Limb Galls ................... 11
Sanitation/Salvage Thinnings .......... 12
Benefits of Research ......................... 12
Summary .............. ................ 12
References ............................ 13
Acknowledgments ......................... 14


Development of the Fusiform Rust
Epidemic

Fusiform rust, a fungus-caused disease which kills
and deforms pines (cover photo), has increased to
epidemic proportion in slash and loblolly pine plantations
throughout extensive areas of the South, including north
Florida, since the late 50s and early 60s. Previously, this
disease, first reported near the turn of the century, was
neither widespread nor prevalent. There is evidence the
disease increased in intensity from Mississippi to the
Atlantic coast and south to Florida. The pathosystem is
endemic (i.e., both host and pathogen are indigenous to
the southeastern USA, which is likely the center of origin
and the region of great genetic diversity in host and
pathogen). The pathogen is not known to occur naturally
outside the southern USA and is most prevalent in the
southeastern USA. The increase in fusiform-rust
incidence and therein its role as a major limiting factor in
the management of slash and loblolly pine over extensive
areas resulted from changes in the forest ecosystem
which occurred as pine management evolved from
extensive to intensive.
The fungus causing fusiform rust is not favored nor
abundant in old growth natural stands but is greatly
favored in young, rapidly growing, pine plantations of
susceptible species, especially when established in high-
rust hazard areas. Young plantations are extremely
vulnerable to the disease in high-rust hazard areas and
more than 90% of rust-susceptible trees can be infected
by the age of 5 years. Also, land-use patterns which
placed susceptible pines in close proximity to the
alternate host (susceptible oaks), (e.g., planting slash and
loblolly pine on former agricultural land where oaks
abound) favored fusiform-rust increase, as did a
reduction in controlled burning and suppression of
wildfires, which favored oak abundance. Research by
state and federal agencies and the forest industry, which
began in the 50s, continues to improve our knowledge of
the biology, ecology and management of this most
serious disease of southern pines.
Current rust hazard zones for fusiform rust in
plantations of slash and loblolly pines (Figures 1A and
1B) show areas of low, moderate and high-rust hazard
(see Table 4 for delineation of rust hazard). Fusiform
rust is estimated to cause 35 million dollars in losses
annually in five southeastern states, including 8 million
dollars in Florida. Table 1 shows the number of acres by
forest type in Florida with high, moderate and low levels
of rust-infected trees.

March 1998


(~ FiI'J~


Page 1








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


Contents

Development of the Fusiform Rust Epidemic ....... 1
Losses to Fusiform Rust ........................... 3
Biology of the Fusiform Rust Pathosystem A
Complex Life-style .......................... 4
Life History .................... ...... 4
Susceptible Species ...................... 5
Pines ... .......................... 5
Oaks ... .......................... 5
Ecology of the Fusiform Rust Pathosystem A Rust
Favorable Environment ....................... 6
Natural Old Growth Forests Contrasted with
Intensively Managed Plantations .......... 6
Critical Factors .................... .6
Pine Regeneration and Growth .......... 6
Susceptible Oaks .................. .. 6
Soils ..... ......... ............. 6
Climate ............................ 7
Improved Planting Stock ............... 7
Management of Fusiform Rust to Reduce Losses .... 7
Evaluating Rust Hazard Risk ............... 7
Reducing Losses in Moderate- and High-
Hazard Areas ....................... 9
Site Preparation .................. ... 9
Rust-resistant Planting Stock ........... 9
Plant Healthy Seedlings .............. 10
Oak Management ................... 10
Delay Fertilization ................... 10
Alternative Species and Silviculture ..... 10
Preventing Rust in Low-Hazard Areas ...... 11
Nursery Planting Stock ............... 11
Encroachment of Oak ................ 11
Treating Infected Stands ................. 11
Replant ........................... 11
Prune Limb Galls ................... 11
Sanitation/Salvage Thinnings .......... 12
Benefits of Research ......................... 12
Summary .............. ................ 12
References ............................ 13
Acknowledgments ......................... 14


Development of the Fusiform Rust
Epidemic

Fusiform rust, a fungus-caused disease which kills
and deforms pines (cover photo), has increased to
epidemic proportion in slash and loblolly pine plantations
throughout extensive areas of the South, including north
Florida, since the late 50s and early 60s. Previously, this
disease, first reported near the turn of the century, was
neither widespread nor prevalent. There is evidence the
disease increased in intensity from Mississippi to the
Atlantic coast and south to Florida. The pathosystem is
endemic (i.e., both host and pathogen are indigenous to
the southeastern USA, which is likely the center of origin
and the region of great genetic diversity in host and
pathogen). The pathogen is not known to occur naturally
outside the southern USA and is most prevalent in the
southeastern USA. The increase in fusiform-rust
incidence and therein its role as a major limiting factor in
the management of slash and loblolly pine over extensive
areas resulted from changes in the forest ecosystem
which occurred as pine management evolved from
extensive to intensive.
The fungus causing fusiform rust is not favored nor
abundant in old growth natural stands but is greatly
favored in young, rapidly growing, pine plantations of
susceptible species, especially when established in high-
rust hazard areas. Young plantations are extremely
vulnerable to the disease in high-rust hazard areas and
more than 90% of rust-susceptible trees can be infected
by the age of 5 years. Also, land-use patterns which
placed susceptible pines in close proximity to the
alternate host (susceptible oaks), (e.g., planting slash and
loblolly pine on former agricultural land where oaks
abound) favored fusiform-rust increase, as did a
reduction in controlled burning and suppression of
wildfires, which favored oak abundance. Research by
state and federal agencies and the forest industry, which
began in the 50s, continues to improve our knowledge of
the biology, ecology and management of this most
serious disease of southern pines.
Current rust hazard zones for fusiform rust in
plantations of slash and loblolly pines (Figures 1A and
1B) show areas of low, moderate and high-rust hazard
(see Table 4 for delineation of rust hazard). Fusiform
rust is estimated to cause 35 million dollars in losses
annually in five southeastern states, including 8 million
dollars in Florida. Table 1 shows the number of acres by
forest type in Florida with high, moderate and low levels
of rust-infected trees.

March 1998


(~ FiI'J~


Page 1








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 2


A
Slash Pine


Ru t Hazard
0 Lou
C Moderate
U High
E Not Rated


B

Loblolly Pine


Rust Hazard
] Low
01 Moderate
I High
E Not Rated


Figure 1. Estimated fusiform-rust-hazard zones for slash (A) and loblolly (B) pine based on USDA Forest Service
Forest Inventory and Analysis data: low = 0 9.9%; moderate = 10 30%; high = >30% trees infected with a stem gall
or potential stem gall (adapted from Starkey et al. 1997).


March 1998


Page 2


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management









Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 3


Table 1. Thousands of acres of pine forests in Florida with fusiform rust at three levels of incidence (adapted from
Starkey et al. 1997).
Rust incidence'

>10% >30% >50%/

Acres Acres Acres
Forest type Total acres % # %# _%

Planted slash 3296 794 242 274 8 121 4

Natural slash 1903 158 8 58 3 30 2

Planted lobloll. 317 99 31 60 19 31 10

Natural loblolly 261 116 44 63 24 30 11

Total/Average 5777' 1167 20 455 8 212 4

1 Rust incidence is % trees with a stem gall (canker) or a branch gall within 12 inches of the stem.
2 % rounded to nearest whole number.
3 Of the total pine acres (5,777,000) 36.5, 51.8 and 11.7% are in non-industrial, industrial and government
ownership, respectively.



Losses to Fusiform Rust


Annual losses to fusiform rust have been estimated
at 35 million dollars in five southern states (FL, GA,
SC, NC and VA) and 8 million dollars in Florida.
Significant rust and losses also occur in AL, MS, and
east TX (Figures 1A and 1B). Losses occur mostly as
mortality to young pines. When 1-5-year old trees
develop stem galls, they often die before rotation age
(harvest) or become deformed and unmerchantable or
reduced in value (cover photo).
Trees with severe stem galls often referred to as
cankers may die throughout the rotation especially if
subjected to high velocity winds. Branch galls on
young trees within 12 inches of the stem often grow
into the stem and become damaging stem cankers,
otherwise branch galls which form on older trees or
further from the stem do not severely impact the tree.
Severely diseased trees may suffer a loss of growth in
the absence of mortality. In high-rust-incidence areas,
severely damaged young plantations are often
destroyed and replanted, adding to costs of
establishment and lengthening rotation age. Further,
rust-infected trees may succumb to other pest problems
(e.g., pitch canker, pitch moth or tip moth).


Damage can also occur when resinous stem cankers
(galls) ignite during prescribed burs or wild fires:
these trees may be killed or reduced in value due to
charring.
A model has been developed (Table 2) to estimate
losses due to rust-associated mortality for unthinned
slash pine plantations at age 20 years as a function of
stem galls at age 5 years and site index (potential pine
growth rate).
To discuss the management options available to
large and small, private and public, forest landowners,
some important attributes of the biology and ecology of
the fusiform-rust pathosystem must be considered.


March 1998


Page 3


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management









Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 4


Table 2. Estimated number of trees surviving and volume loss to fusiform-rust-caused mortality for slash pine in unthinned plantations at
age 20 years as a function of percentage stem galls at age 5 years and site index adapted from Nance et al. 1982).
Site index

40,60,80 40 60 80 80

Stem rust age 5 r Sun giving trees age 20 M rs Volume loss age 20 yrs

(%) ------(#,ac ------ -----------(cu ft'ac)----------- cdac'
0 621 0 0 0 0
10 555 33 142 347 2.7
20 489 72 292 537 4.2
30 424 118 424 794 6.2

40 359 168 600 1114 8.7

50 296 125 771 1474 11.5
60 238 291 987 1914 15.0
70 171 362 1251 2420 18.9

SSite index is a measure of the quality of a site and is quantified by the average height of the dominant (tallest) trees on the site at age 25
years.
2 Loss based on 128 cu ft/cd; growth of 2 cd/ac/yr.
Life History


Biology of the Fusiform Rust
Pathosystem A Complex Life-style


The life history of the fusiform rust
pathosystem is complex (Figure 2).


(Dicaryotizationj Ssci \o Telia (2N)
SBasidia & sidiospore (IN) (Caryogamy)
Figure 2. Life history (disease cycle) diagram of fusiform rust showing spore
stages and symptoms on pine and oak. See text for further description. N =
nuclear stage of spores (as drawn by W. A. Carey in Dinus and Schmidt 1997).


March 1998


Page 4


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management








Fusiform~_ RutDsaeo otenPns iloy clg n aaeetPg


The important aspects of the disease cycle are:
1) the fungus pathogen, Cronartium quercuum f. sp.
fusiforme, is an obligate parasite requiring two
living host trees pine and oak to complete its life
cycle; the fungus cannot spread from pine to pine,
but must return to oak to produce the spores which
in turn infect pine; 2) the fungus produces five
distinct spore types, each with a unique function -
two types (pycniospores and aeciospores) occur on
galls on pine stems and branches, and three types
(urediniospores, teliospores and basidiospores) occur
on the underside of oak leaves; 3) tender young oak
leaves are infected in the spring by wind-borne
aeciospores produced on pine, and new pine leaders
are infected later in the spring by wind-borne
basidiospores from oak leaves; 4) the fungus does not
require a wound to infect the oak or pine hosts, but can
infect emerging succulent, healthy host tissue, directly
or through stomata; hardened tissue of oak and pine
cannot be infected by the fungus; 5) spores of the
fungus require moisture for germination and infection
of pine and oak; 6) the fungus is perennial in living
pine tissues, causing a hypertrophy or gall. The gall is
often colonized by other fungi and insect pests which
deteriorate and weaken the galled portion of the tree
(Figure 3). The fungus is annual in oak leaves: dying
with defoliation in the fall and recurring with infection
of oak from the orange aeciospores produced on the
pine galls in the spring. Little or no damage occurs to
oak trees, although severely infected leaves may die.


Cp! -'

,o


Figure 3. Stem and branch galls caused by the fusiform
rust fungus on a loblolly pine. These galls are covered
with yellow-orange aeciospores which are wind-
disseminated and infect emerging oak leaves in the
spring.


Susceptible Species

Pines. Of the commercially important pine
species, slash pine (Pinus elliottii var. elliottii) and
loblolly pine (P. taeda) are very susceptible to fusiform
rust; longleaf pine (P. palustris) is less susceptible, and
shortleafpine (P. echinata) is considered immune.
Pond pine (P. serotina) is intermediate between
loblolly and longleaf, and spruce pine (P. glabra) is
essentially immune. Sand pine (P. clausa) is not
thought to be susceptible to fusiform rust but is
damaged by a related pine-oak rust disease.
Oaks. Twenty of the southern red oaks can be
infected by aeciospores of the fusiform rust fungus
(Table 3). The most important oak host in many areas
in Florida is water oak (Quercus nigra) but prevalent
and important oak species can vary among habitats.
Several species of pine from the western U.S. and
California black oak are very susceptible when
artificially inoculated, but the disease does not occur
naturally on these species.


Table 3. Relative susceptibility of southern oaks to
Cronartium quercuum f. sp.fusiform (adapted from
Dwinell 1974).

Oak host' Rank: Oak Host Rank

Water la3 Blackjack 6cd

Willow 2a Southern red 7cde

Cherrybark 3b Northern red 8de

Bluejack 4b Turkey 9de

Running 5bc Laurel IOef

Other oaks of lesser susceptibility are swamp
chestnut, scarlet, overcup, chestnut, black, dwarf
live, sand live, post and dwarf post.
2 Ranked from most susceptible to least susceptible
on the basis of number of telia/cm2 of leaf surface
area following artificial inoculation of seedlings.
3 Ranks not followed by the same letter are
significantly different (p = 0.05) for telia/cm2 of oak
leaf surface area.


March 1998


Fusifdrm Rust Disease of Southern Pines: Biology, Ecology and Management


Page 5








Fusiform Rust Disease of Southern Pines: Biology,_Ecology and Management Page 6


Ecology of the Fusiform Rust
Pathosystem A Rust Favorable
Environment

Environmental factors (climatic, edaphic and
biotic) including human activities significantly affect
pathogens and the diseases they cause. Fusiform rust
is no exception. Research has identified certain critical
environmental factors in the biology and ecology of the
fusiform rust pathosystem, including management
practices which can influence the rust epidemic and
help to explain why the disease has reached epidemic
proportions in intensively-managed pine plantations
and naturally regenerated old fields.

Natural Old Growth Forests Contrasted with
Intensively Managed Plantations

In the natural forest, essentially devoid of human
activity, indigenous (native) pathogens and indigenous
hosts most often reach a balance, such that both
organisms co-exist without severely limiting one
another. Such was the case historically (at least in the
recent past) with fusiform rust in natural pine forests
where this indigenous rust was of limited occurrence
and caused little damage. Earlier unchecked natural
fires and those set by Indians and early settlers likely
limited oak populations and fusiform rust incidence.
However, in our desire (and need) for more productive
forests, with more intensive forest management, we
have created conditions very favorable for fusiform
rust to increase and spread. To redress the balance and
reduce losses to fusiform rust, the critical factors which
have caused increased rust incidence must be identified
and their role in the epidemic understood. It should
also be noted that natural forests newly seeded onto old
fields also have a high incidence of fusiform rust. This
is especially true of loblolly pine, often called "old
field pine".

Critical Factors

Pine Regeneration and Growth. Since World
War II intensive planting efforts have replaced natural
regeneration and resulted in extensive areas of young,
rapidly growing susceptible slash and loblolly pine
plantations. This most successful regeneration effort
has significantly altered the species and age


composition of the pre-existing forest, in favor of the
rust pathogen and resulting disease. Old growth
forests often of the more rust-resistant longleaf pine -
were replaced by young plantations of the more
susceptible slash and loblolly pines. For example, in
Florida, pine plantations increased from an estimated
291 thousand acres in 1952 to 5.59 million acres by
1990. In the Southeast, this increase was from 1.0 to
22.6 million acres. The shift to younger age classes
accompanying the increase in plantations has
contributed greatly to the increase in rust incidence.
Abundant, succulent, new pine growth (leaders) are
very susceptible to infection by the fungus. While
many pathogens grow best in weakened trees, the
fusiform-rust pathogen infects and grows best in
healthy, rapidly growing trees. The more rapidly a tree
grows, the more it is at risk to the fungus. Thus, most
practices which improve pine growth (e.g.,
fertilization, vegetative competition control, genetic
growth rate improvement, and intensive site
preparation) favor rust development. This presents a
dilemma to forest landowners when rapid reforestation
and increased productivity are management goals.
Susceptible Oaks. The red oaks (Table 3),
which serve as the alternate host of the pathogen and
the source of inoculum (spores) for the infection of
pine, are critical for disease development. In the
absence of susceptible oaks, there would be no
fusiform rust of pine since the fungus cannot spread
from pine to pine. Generally, the potential for rust on
pines increases with the abundance and nearness of
infected oaks. However, because the spores are
microscopic in size, produced in great abundance and
wind-borne, they are apparently transported in large
quantities over long distances from oak to infect pine.
Pines growing one-half mile or more from infected
oaks can be infected.
On the drier upland sites where oaks can flourish
in the absence of fire, reduced prescribed burning and
absence of wildfires, which has occurred over the last
50-70 years, has favored oak regeneration and allowed
oaks and rapidly growing young pines to occur in close
proximity. Incentive programs have resulted in an
increase of planting of former agricultural sites (i.e.,
drier sites where oaks flourish). Also, some
silvicultural practices can favor oak regeneration (see
Site Preparation, below).


March 1998


Page 6


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 7


Soils. Moderately to well-drained soils with a
sandy surface and an organic horizon, but lacking a
spodic horizon (CRIFF E & F soils)', are associated
with high-rust incidence, while the wetter, poorly
drained, flatwood soils with a spodic horizon (CRIFF
C & D soils) are associated with low-rust incidence.
These relationships exist because the better drained
soils support an abundance of the alternate oak host,
while the poorly drained flatwood soils do not favor
oaks. Thus, soils are an indicator of oak and therein of
rust hazard. This relationship, however, applies best to
extensive areas and those unaltered by silvicultural
practices which favor fusiform rust increase and
spread, and soil samples alone cannot be relied on to
predict rust hazard at the individual stand level due to
long-distance dissemination of spores of the pathogen.
Climate. Fusiform rust has special climate
requirements for rapid spread and development. Most
important is surface moisture in the form of rain or
dew on succulent oak leaves and pine leaders, which
favor the production of spores, spore germination and
subsequent infection of the hosts. Unfortunately, over
extensive areas of the southeast, both moisture and
temperature are favorable for disease development
much of the time. This is especially true in young pine
plantations where abundant plant surface moisture
occurs for long periods during the critical spring
season when sporulation and infection occur. There is
some indication that fusiform rust is limited in the west
(Texas) and the north (NC) by a lack of sufficient
moisture and low temperatures, respectively. It is also
apparent that rust incidence varies among years
depending in part on favorable or unfavorable weather
at critical periods in the rust life cycle.
Improved Planting Stock. Species of pine and,
more importantly, some genotypes within slash and
loblolly pine, vary in their susceptibility or resistance
to fusiform rust. Planting rust-susceptible pines
increases the risk to fusiform rust, especially in high-
rust incidence areas (see Rust Resistant Planting
Stock, below).



1.The Cooperative Research in Forest Fertilization (CRIFF) program at the
School of Forest Resources and Conservation, University of Florida, has
defined eight soil types (A-H) which are widely used in forest soil
management, especially with respect to fertilization. Type E and F are
moderately-well to well-drained soils lacking a spodic horizon and having
an argillic (clay) layer at depths of approximately 10-50 inches.


Management of Fusiform Rust to
Reduce Losses

Proactive prevention of disease is a fundamental
principle of effective forest disease control. This
principle is especially appropriate for fusiform rust
which causes most severe impact in young plantations.
When a young plantation is infected, there are few
effective remedies to reduce economic losses. Thus,
preventing rust is most important. Management
recommendations vary in high- versus low-rust hazard
areas, and rust-hazard risk must be evaluated.

Evaluating Rust Hazard Risk

Prior to planting, the potential risk of rust
occurrence can be described as follows:
High-rust hazard: >30% pines infected*
(approximately > 15% stems infected at age 5
years).
Moderate-rust hazard: 10-30% pines
infected (approximately 5-15% stems infected
at age 5 years).
Low-rust hazard: <10% pines infected
(approximately 5% stems infected at age 5
years).
*Percentage trees infected are those with a stem gall or
branch gall on a living branch within 12 inches of the
main stem (adapted from Starkey et al. 1997).

High- and low-rust incidence areas, which have
remained so for many years (Figure 4) can be assessed
by defining critical factors, e.g., 1) the amount of rust
in nearby susceptible pine stands, 2) the presence of
susceptible oaks, 3) the soil type, and 4) site quality
(Table 4). In addition to assessing risk, the product
objectives of the landowners should be considered:
recommendations could differ for short-rotation
pulpwood as compared with longer-rotation solid wood
products.


March 1998


Page 7


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management









Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


Table 4. Estimating fusiform rust-hazard risk.

Rust in
Hazard Susceptible nearby Site quality/i
or risk oaks pine Soil type Growh rate
stands

High Abundani in and > 30% Moderately to High-rapid
round plantation infected moderatel. well growth
drained

Mod- Present in or 20-30o Poorly to Moderate-
crate around area but infected moderately well rapid growth
scattered and not drained
abundant

Low Lacking or few < 109% Poorly drained Low-slow
within '.,' mile infected natwood growth
__ spodosols

Data from row-plot progeny tests, which estimate
rust impact, show the increase in rust incidence with
age (Figure 5) and the associated rust mortality (RAM)
at age 23 years given the percentage of trees infected at
age 5 years.
For example, a plantation with 50% of the trees
infected at age 5 years (R05) is predicted to have
approximately 90% of the trees infected at a pulpwood
harvest age of 23 years (Figure 5). This same
plantation is predicted to have 35% rust associated-
mortality (RAM) at age 23 years (Figure 6).
100


61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
YEAR PLANTED

Figure 4. Average fusiform rust incidence (% trees
infected) by year planted in a 5-year-old slash pine
plantation from 1962-1980 in a typical low-hazard
area (ave = 9.5%, n = 253 plantations) and a high-rust
hazard area (ave = 44.1%, n = 215 plantations)
(adapted from Schmidt and Allen 1991).


U
z
I 0.6

z
1-
a 0.4


0.2


R105

.45
.40
.35
.30
.25
.20

.15

.10

.05


5 10 15 20 23
AGE


Figure 5. Predicted cumulative incidence of fusiform rust
(proportion trees infected) in a slash pine progeny test at
ages 6-23 years as a function of rust incidence at age 5 years
(RI05) and plantation age (unpublished data adapted by J.
E. Allen and R. A. Schmidt, from the Cooperative Forest
Genetics Research Program, SFRC, IFAS/UF).





0.5

RIO5
S0.4 .60
.ra .55
.50
0.3 .4
.40
W .35
02 -.30
0.2 .25
.20
< .15
0.1 .10
.05








trees with rust) at age 5 years (RI05) with a RAM at age 5
5 10 15 20 23
AGE

Figure 6. Predicted cumulative rust-associated mortality
(RAM = proportion dead) in slash pine progeny tests at
ages 6-23 years as a function of rust incidence (proportion
trees with rust) at age 5 years (RI05) with a RAM at age 5
years (RAM05) of 0.011 (unpublished data adapted by J.
E. Allen and R. A. Schmidt from the Cooperative Forest
Genetics Research Program, SFRC, IFAS/UF).


March 1998


Page 8









Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 9


Reducing Losses in Moderate- and High-
Hazard Areas

Site Preparation. Site preparation decisions
illustrate the dilemma regarding rapid growth and its
association with increased rust susceptibility. Site
preparation should follow rules of good silviculture,
especially as related to soils, and be compatible with
landowner objectives and capital. That is, fertilizer,
weed control, cultivation and bedding (when
appropriate on poorly drained soils) will promote rapid
growth and increase productivity. However, it will
likely increase the percentage of rust-infected trees.
One added advantage of intensive management is the
opportunity to reduce on-site oak, chemically or
mechanically. Site preparation practices which may
increase or retain oaks on high-hazard sites should be
avoided. Some forms of mechanical site preparation
promote development of oak sprouts. For example, in
one study KG (shearing standing, residual trees
[following harvest] at or below the ground line) and
discing promoted the fewest sprouts while chopping
without discing promoted the greatest number of oak
sprouts (Figure 7). Site preparation by windows,
which incorporate large amounts of soil and prevent
complete burning of piled debris, may create soil
conditions in the window which favor oak
regeneration.













24
YA LL L


Figure 7. Number of oak rootstocks following four
mechanical site preparation treatments in a high-fusiform-
rust hazard area (Belanger et al. 1995).


Rust-Resistant Planting Stock. The best
management tool to prevent or reduce rust losses is
rust-resistant seedlings. Rust-resistant genotypes of
slash and loblolly pine have been developed by
research scientists at state and federal laboratories and
the forest industry and are available at many nurseries.
Although large quantities of the best rust-resistant seed
are in short supply and some rust-improved varieties
are more resistant than others (no families are immune
(i.e., disease free)), rust-resistant seedlings can reduce
rust incidence by 20 to 80% in high-rust hazard areas
(Figure 8, Table 5), with little or no reduction in
growth (see Benefits of Research below).
Due to their short supply, rust-resistant seedlings
should only be used in moderate- to high-rust hazard
areas. Because most rust-improved seedlings currently
available are from an open-pollinated, maternal, parent
tree (only the mother tree is of known resistance), not
all seedlings in the family are resistant. Nevertheless, a
higher percentage of seedlings from rust-improved
families would be rust resistant. At present, there is no
standard rating at nurseries which reports the degree of
disease resistance for rust-improved seedlings. Not all
"genetically improved" seedlings have rust resistance;
some are only improved for growth. These seedlings
would not be appropriate to plant in high-rust hazard
locations.


100
100 FAMILY
90 P ...... ...4... .-.-.--..... -

-o. '" ..- -
80
70---- 2
60.

:40
30
20

0

Years
Figure 8. Fusiform rust incidence (% trees infected)
at ages 1-5 years in open-pollinated families of rust-
susceptible (I and 2S) and rust-resistant (3-7R) slash
pine planted in a high-rust hazard site in north central
Florida (adapted from Schmidt and Wilson 1997).


March 1998


Page 9


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management









Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page_10


Table 5. Fifth year fusiform rust incidence on susceptible and resistant loblolly and slash pine and reduction in rust
incidence due to planting rust-resistant families in operational plantations in high-rust incidence areas. (Adapted from
Schmidt et al. 1985)
Rust incidence (%)

Location Species Rust susceptibility No. of plantations Acres Mean Reduction
FL Slash Susceptible 88 6070 49.1
58.2
Resistant 22 1569 20.5

Loblolly Susceptible 14 765 35.6
69.1
Resistant 24 1447 11.0

GA LoblollN Susceptible 82 4133 31.4
52.2
Resistant 46 5330 15.0

GA Lobloll. Susceptible 71 4116 44 4
72.1
Resistant 61 9770 12.4

Summar) Susceptible E 255 E 15084 A e. 40 1
Ave. 63.0
Resistant S 153 18116 Ate. 14.7


Plant Healthy Seedlings. In most nurseries
(especially those in high-rust hazard areas) fusiform rust
is effectively controlled with the systemic chemical
Bayleton. Bayleton, applied as a seed treatment
and/or sprayed on seedlings, is systemic, (i.e., it is
absorbed and translocated within the seedling, protecting
actively growing susceptible tissues). Since the chemical
is in the seedling, it is not eroded by rain or irrigation.
Bayleton not only prevents infection, but is reported to
eradicate newly established infections. Bayleton
applied in the nursery may have some residual effect
immediately after outplanting, but will not long protect
newly planted seedlings in the field. Bayleton applied
to seedlings and small trees (1 to 3 years) in the field has
been reported to provide rust protection. However, it is
difficult to protect trees beyond 3 to 5 years of age with
chemical sprays applied from the ground because of the
expenses and difficult logistics of application. Currently
Bayleton is not recommended subsequent to
outplanting, except in special circumstances (e.g. seed
orchards, ornamental trees or trees in research plots).
Oak Management. Reducing the abundance of
oaks should be encouraged as part of the standard
operational procedures during harvest and plantation
establishment. In addition to reducing hardwood
competition, spores which infect pine come from infected


oak and reduction of oak should reduce rust incidence.
However, because spores are wind-disseminated over
great distances (perhaps V' to 1 mile), there is no
assurance that removing oaks from a plantation and
immediate surrounding area will significantly reduce
rust incidence if spores come from adjacent oak,
beyond the oak removal zone. Thus, reducing oaks
solely for the purpose of reducing rust incidence may
not be effective. Prescribed fire and herbicides can
provide effective oak control in established stands.
However, if resinous stem galls on pine are ignited,
trees may be killed and charring may degrade wood for
some uses.
Delay Fertilization. In high-hazard areas, it may
be possible depending on soil type or landowner
objectives to delay fertilization until mid-rotation in
order to prevent the rapid growth and associated
susceptibility of young trees when they can be severely
impacted by early developing stem cankers. For
example, on soils that do not require early fertilization
for seedling survival and early growth or in
management systems for longer, solid wood rotations,
delaying fertilization may be appropriate.
Alternative Species and Silviculture. On
appropriate sites, longleaf pine, thought to be more
naturally resistant to the fusiform rust fungus, or the


March 1998


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Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 11


naturally immune shortleaf pine may be good alternatives
for planting. There is evidence to suggest that a
shelterwood silvicultural system (natural regeneration of
pines beneath an overstory of seed trees) can result in
reduced rust incidence on understory regeneration,
perhaps by creating unfavorable climate conditions (e.g.,
reduced surface moisture on understory regeneration).
Additionally, prescribed fire, especially summer burs,
can reduce oak abundance.

Preventing Rust in Low-hazard Areas

Few precautions need be taken on low-rust hazard
sites. Rust incidence, especially damaging stem cankers,
will likely be infrequent and losses will be minimal.
However, there are two precautions which should be
observed. These concern rust-free planting stock and the
invasion of susceptible oak hosts.
Nursery Planting Stock. Given that there is, at
present, a limited supply of highly resistant seedlings,
fast growing families (genetically improved seedlings)
lacking rust resistance are best planted on low-rust
hazard sites. However, because these seedlings are
susceptible, growers should insure that seedlings are
obtained from a nursery which protects trees from rust
infection prior to lifting. Otherwise, infected seedlings
with galls (Figure 9) or without visible galls (latent


Figure 9. Fusiform rust galls on slash pine seedlings in the
nursery bed.


infections) may be planted and trees will die early in
the rotation. Further, if these infected trees sporulate
before they die, they could introduce rust into an
otherwise rust-free area and increase the rust hazard of
the site, creating problems for the current and future
plantings (see Planting Healthy Seedlings, above).
Encroachment of Oak. It is important that low
hazard sites without significant numbers of oak remain
so. Thus, harvest and site preparation practices
(including drainage to reduce soil moisture and
elimination of control burns) which could favor the
establishment of susceptible oaks, should be avoided
(see Site Preparation and Oak Management, above).

Treating Infected Stands

Stands which have become infected can be
managed or treated in several ways to reduce losses.
Replant. If a young plantation is severely
infected (>50% stems infected prior to age 3 to 5
years), consideration should be given to destroying the
plantation and replanting, especially if landowner
objectives are for pulpwood. It is not advisable to
remove diseased trees and interplant since the newly
planted trees will not compete well with the older
established trees. An alternative might be to manage
for fewer stems and longer rotations (e.g., for solid
wood products). In this case, the severely infected
trees, those with stem cankers or limb galls likely to
grow into the stem, could be removed in
precommercial or commercial harvests (see
Sanitation/Salvage Thinnings,below).
Prune Limb Galls. Because a large percentage
of limb galls within 12 inches of the stems on young
trees grow into the stem within a few years, it may be
beneficial to prune limb galls, thereby preventing
damaging stem galls. Currently, this practice is only
economically feasible on ornamental trees, but is
impractical for extensive plantings to be used for
pulpwood. If landowner objectives are for longer
timber rotation (sawlogs), pruning has added
silvicultural and wood quality advantages and may be
economically feasible. However, because wounds can
be colonized by the fungus, pruning should not occur
during the season March July when basidiospores
may be present.
Sanitation/Salvage Thinnings. A
sanitation/salvage thinning at mid-rotation age or
beyond should remove diseased trees. This thinning


March 1998


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


Page 11








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 12


practice, when done in conjunction with normal thinning
operations, can improve the residual stand and utilize
trees which otherwise would likely be lost to rust
mortality before normal harvest age. Thinnings should
be carefully considered, however, to avoid residual pines
being attacked by the annosum root rot fungus and/or
southern pine beetle, if these pests are present in the area
and/or environmental conditions are favorable for pest
attack.

Benefits of Research

Often the realized monetary benefits which accrue to
the expenditure of dollars to support research are difficult
to assess and poorly documented. Recently the U.S.D.A.
Forest Service, using Forest Inventory and Analysis and
data from several state and federal research projects,
completed a benefit/cost analysis of dollars spent on
fusiform rust research in the South. While the report
focuses on the development and deployment of rust-
resistant slash and loblolly pine seedlings, this critical
aspect of reducing losses to fusiform rust would not have
been possible without associated research in other areas
of rust biology and ecology.
The successful development of rust resistance in
southern pines began in the early 1950s and continues
today pointing out the significance oflongterm
research in forestry. A further hallmark of this successful
effort has been the cooperation among scientists from
state and federal laboratories, universities and industry.
Again, while the focus is on pathologists and geneticists
working together, many other disciplines have made
significant contributions.
Information (Table 6) adapted from the U.S.D.A.
Forest Service report Positive Returns from Investments
in Fusiform Rust Research indicates that for every dollar
spent on rust research a return of 6 to 20 dollars was
realized, depending on product utilization and optimum
deployment of rust-resistant seedlings. The net present
value (PV) varies from approximately 245 to 949 million
dollars. Among all options considered, B/C ranged from
2.2 20.4 and PV ranged from 59 949 million dollars.
These figures represent an annual gain of 5-20 million
dollars overall in the South.


Table 6. Benefit/cost ratio (B/C) and net present
value (PV) from investments in fusiform rust
research in slash and loblolly pine (adapted from
Pye et al. 1997).

Benefit Optim
Utilization' measure deployment'

Poor B/C 20.4
PV 949.7

Pulpwood B/C 14.1
PV 638.2

Sawtimber B/C 6.9
PV 287.9

Full B/C 6.0
PV 245.0
Assume a fixed 35-year rotation: poor. any tree with
a stem gall is left in woods; pulpwood, any tree with a
stem gall is pulped; sawtimber, infected tree pulped
unless a 16 ft sawlog section is free of stem gall; full,
optimum product utilization of all trees, including trees
with rust galls.
2 B/C, benefit/cost ratio; PV, net present value in
millions of constant 1992 dollars.
3 Optim deployment, rust-resistant seedlings were
deployed in high-rust hazard areas where benefits
would be greatest.

Summary

Intensively managed plantations of slash and
loblolly pines are severely damaged by fusiform rust in
extensive areas throughout the South and significant
financial losses occur. This report summarizes
important aspects of the biology, ecology and
management of this disease which can severely limit
the productivity of southern pine forests, including
those in Florida. The critical environmental factors
which affect rust incidence and spread are discussed,
including the significant role of man, both in creating
and solving the problem. Potential rust incidence, rust-
associated mortality and volume losses are estimated.
Criteria for rust-hazard risk evaluations are provided in


March 1998


Page 12


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management Page 12


practice, when done in conjunction with normal thinning
operations, can improve the residual stand and utilize
trees which otherwise would likely be lost to rust
mortality before normal harvest age. Thinnings should
be carefully considered, however, to avoid residual pines
being attacked by the annosum root rot fungus and/or
southern pine beetle, if these pests are present in the area
and/or environmental conditions are favorable for pest
attack.

Benefits of Research

Often the realized monetary benefits which accrue to
the expenditure of dollars to support research are difficult
to assess and poorly documented. Recently the U.S.D.A.
Forest Service, using Forest Inventory and Analysis and
data from several state and federal research projects,
completed a benefit/cost analysis of dollars spent on
fusiform rust research in the South. While the report
focuses on the development and deployment of rust-
resistant slash and loblolly pine seedlings, this critical
aspect of reducing losses to fusiform rust would not have
been possible without associated research in other areas
of rust biology and ecology.
The successful development of rust resistance in
southern pines began in the early 1950s and continues
today pointing out the significance oflongterm
research in forestry. A further hallmark of this successful
effort has been the cooperation among scientists from
state and federal laboratories, universities and industry.
Again, while the focus is on pathologists and geneticists
working together, many other disciplines have made
significant contributions.
Information (Table 6) adapted from the U.S.D.A.
Forest Service report Positive Returns from Investments
in Fusiform Rust Research indicates that for every dollar
spent on rust research a return of 6 to 20 dollars was
realized, depending on product utilization and optimum
deployment of rust-resistant seedlings. The net present
value (PV) varies from approximately 245 to 949 million
dollars. Among all options considered, B/C ranged from
2.2 20.4 and PV ranged from 59 949 million dollars.
These figures represent an annual gain of 5-20 million
dollars overall in the South.


Table 6. Benefit/cost ratio (B/C) and net present
value (PV) from investments in fusiform rust
research in slash and loblolly pine (adapted from
Pye et al. 1997).

Benefit Optim
Utilization' measure deployment'

Poor B/C 20.4
PV 949.7

Pulpwood B/C 14.1
PV 638.2

Sawtimber B/C 6.9
PV 287.9

Full B/C 6.0
PV 245.0
Assume a fixed 35-year rotation: poor. any tree with
a stem gall is left in woods; pulpwood, any tree with a
stem gall is pulped; sawtimber, infected tree pulped
unless a 16 ft sawlog section is free of stem gall; full,
optimum product utilization of all trees, including trees
with rust galls.
2 B/C, benefit/cost ratio; PV, net present value in
millions of constant 1992 dollars.
3 Optim deployment, rust-resistant seedlings were
deployed in high-rust hazard areas where benefits
would be greatest.

Summary

Intensively managed plantations of slash and
loblolly pines are severely damaged by fusiform rust in
extensive areas throughout the South and significant
financial losses occur. This report summarizes
important aspects of the biology, ecology and
management of this disease which can severely limit
the productivity of southern pine forests, including
those in Florida. The critical environmental factors
which affect rust incidence and spread are discussed,
including the significant role of man, both in creating
and solving the problem. Potential rust incidence, rust-
associated mortality and volume losses are estimated.
Criteria for rust-hazard risk evaluations are provided in


March 1998


Page 12


Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management








Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


order to consider effective rust management, which is
discussed in some detail. The important role of the
successful development and deployment of rust-resistant
seedlings is emphasized. Finally, the beneficial and
extremely cost-effective role of regional, longterm
fusiform rust research is discussed.


References

Anderson, R.L., J.P. McClure, N.D. Cost, and R.J.
Uhler. 1986. Estimating fusiform rust losses in five
southeast states. South. J. Appl. For. 10:237-240.

Anderson, R.L., R.A. Schmidt, and G.A. Snow. 1984.
Integrated pest management in regeneration early
growth phase of pine stands diseases. Pages 45-71
in: S.J. Branham and G.D. Hertel, eds. Proc.
Integrat. For. Pest Manage. Symp. Athens, GA. 281
p.

Belanger, R.P., T. Miller, R.A. Schmidt, and J.E. Allen.
1995. Relation of mechanical site preparation to oak
abundance, pine growth, and fusiform rust incidence
in a slash pine plantation. Interim Res. Rept. 34,
Integrat. For. Pest Manage. Coop., Sch. For.
Resourc. Conserv., Univ. Fla., Gainesville. 12 p.

Dinus, R.J. 1974. Knowledge about natural ecosystems
as a guide to disease control in managed forests.
Pages 184-190. in: Proc. Amer. Phytopathol. Soc.
Vancouver, B.C.

Dinus, R.J. and R.A. Schmidt, eds. 1977. Management
of fusiform rust in southern pines. Symp. Proc.,
Univ. Fla., Gainesville. 163 p.

Dwinell, L.D. 1974. Susceptibility of southern oaks to
Cronartiumfusiforme and Cronartium quercuum.
Phytopathology 64:400-403.

Dwinell, L.D. and H.R. Powers, Jr. 1974. Potential for
southern fusiform rust on western pines and oaks.
Plant Dis. Rept. 58: 497-500.

Goddard, R.E. and 0.0. Wells. 1977. Susceptibility of
southern pines to fusiform rust. Pages 52-58 in: R.J.
Dinus and R.A. Schmidt, eds. Management of


fusiform rust in southern pines. Symp. Proc. Univ.
Fla., Gainesville. 163 p.

Griggs, M.M. and R.A. Schmidt. 1977. Increase and
spread of fusiform rust. Pages 32-38 in: R.J.
Dinus and R.A. Schmidt, eds. Management of
fusiform rust in southern pines. Symp. Proc. Univ.
Fla., Gainesville. 163 p.

Hedgcock, G.G. and P.V. Siggers. 1949. A
comparison of pine-oak rusts. U.S. Dept. Agric.
Tech. Bull. 978. 30 p.

Kelley, W.D. and G.B. Runion. 1991. Control of
fusiform rust on loblolly and slash pine seedlings
in forest nurseries in the southeastern United
States. Pages 338-340 in: Y. Hiratsuka, J.K.
Samoil, P.V. Blenis, P.E. Crane and B.L. Laishley,
eds. Rusts of pine. Proc. Internal. Union For. Res.
Org. Work. Party Conf., Banff, Alberta, Can. Info.
Rept. NOR-X-317. 408 p.

Nance, W.L., R.D. Froelich, T.R. Dell, and E.
Shoulders. 1982. A growth and yield model for
unthinned slash pine plantations infected with
fusiform rust. Pages 275-282 in E.P. Jones, Jr.,
ed., Proc. 2nd Biennial So. Silvicul. Res. Conf.
Atlanta, Ga. 514 p.

Powers, H.R., Jr. 1975. Relative susceptibility of five
southern pines to Cronartium quercuum. Plant
Dis. Rept. 59:312-314.

Powers, H.R., Jr., J.P. McClure, H.A.Knight, and G.F.
Dutrow. 1975. Fusiform rust: forest survey
incidence data and financial impact in the south.
U.S. Dept. Agric. For. Serv., Southeast. For. Exp.
Stn. Res. Pap. SE-127. 16 p.

Powers, H.R., Jr., T. Miller, and R.P. Belanger. 1993.
Management strategies to reduce losses from
fusiform rust. South. J. Appl. For. 17:146-149.

Pye, J.M., J.E. Wagner, T.P. Holmes, and F. W.
Cubbage. 1997. Positive returns from investment
in fusiform rust research. Res. Pap. SRS-4.
Asheville, NC. U.S. Dept. Agric. For. Serv.
South. Res. Stn. 55 p.


March 1998


1


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Fusiform Rust Disease of Southern Pines: Biology, Ecology and Management


Rowan, S.J., W.H. McNab, and E.V. Brender. 1975.
Pine overstory reduces fusiform rust in underplanted
loblolly pine. U.S. Dept. Agric. For. Serv. Res. Note
SE-212.60, 6 p.

Schmidt, R.A. 1978. Diseases in forest ecosystems: the
importance of functional diversity. Pages 287-315
in: J.G. Horsfall and E.B. Cowling, eds. Plant
Disease: An Advanced Treatise. Vol. II. How
disease develops in populations. Acad. Press., New
York. 436 p.

Schmidt, R.A. and J.E. Allen. 1991. Temporal and
spatial variation affecting fusiform rust hazard
prediction in slash pine plantations in the
southeastern United States. 1991, Pages 139-
148.in:Y. Hiratuska, J.K. Samoil, P.V. Blenis, P.E.
Crane, and B.L. Laishley, eds. Proc. Inteml. Union
For. Res. Org. Work. Party Conf. Rusts ofpine,.
Banff, Alberta, Canada. Info. Rept. NOR-X-
317.408p:

Schmidt, R.A. and J.E. Allen. 1995. Geographic
variation in fusiform rust incidence on progeny of
open-pollinated resistant and susceptible slash pine
families in the Coastal Plain. Integrate For. Pest
Manage. Coop., Interim Res. Rept. 35. Sch. For.
Resourc. Conserv., Univ. Fla. Gainesville. 44 p.

Schmidt, R.A., J.E. Allen, R.P. Belanger, and T. Miller.
1995. Influence of oak control and pine growth on
fusiform rust incidence in young slash and loblolly
pine plantations. South. J. Appl. For. 19:151-156.

Schmidt. R.A., R.C. Holley, and M.C. Klapproth. 1985.
Results from operational plantings of fusiform rust
resistant slash and loblolly pines in high rust
incidence areas in Florida and Georgia. Pages 33-41
in: J. Barrows-Broaddus and H.R. Powers, Jr., eds.
Proc. Internl. Union For. Res. Org. Rust of hard
pines Work. Party Conf. S2-06-10. Athens, GA.
331 p.

Schmidt, R.A., E. J. Jokela, J.E. Allen, R.P. Belanger,
and T. Miller. 1990. Association between fusiform
rust incidence and CRIFF soil classification for slash
pine plantations in the Coastal Plain of Florida and
Georgia. South. J. Appl. For. 14:39-43.


Schmidt, RA. and M.C. Klapproth. 1982. Delineation
of fusiform rust hazard based on estimated volume
loss as a guide to rust management decisions in
slash pine plantations. South. J. Appl. For. 6:59-
63.

Schmidt. R.A., H.R. Powers, Jr., and G.A. Snow.
1981. Application of genetic disease resistance for
the control of fusiform rust in intensively managed
southern pine. Phytopathology 71:993-997.

Schmidt, R.A. and D. Wilson. 1997. Geographic
variation in fusiform rust incidence on progeny of
resistant and susceptible slash pine families in the
Coastal Plain: rust virulence study third planting
established in 1991. For. Biology Res. Coop.,
Sch. For. Resourc. Conserv., Univ. Fla.
Gainesville. 36 p.

Starkey, D.A., R.L. Anderson, C.H. Young, N.D. Cost,
J.S. Vissaage, D.M. May, and E. K. Yockey. 1997.
Monitoring incidence of fusiform rust in the South
and change over time. U.S. Dept. Agric. For. Serv.,
South. Region For. Health Prot. Rept. R8-PR30. 29
p.


Acknowledgments


Many scientists from state, federal and industry
laboratories have contributed to the information
contained herein and I have attempted to show
appropriate credit both in the tables and figures, and in
the literature references. Much of the information comes
from the research programs of School of Forest
Resources and Conservation, Institute of Food and
Agricultural Sciences, University of Florida, both
published and unpublished, as noted. In many instances,
the forest industry played a major role through their
participation in the Integrated Forest Pest Management
Cooperative, the Cooperative Forest Genetics Research
Program and the Cooperative Research in Forest Tree
Fertilization in the School of Forest Resources and
Conservation.


March 1998


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Page 14











































































Florida Agricultural Experiment Station, Institute of Food and Agricultural Sciences, University of Florida, Richard L. Jones, Dean for Research,
publishes this information to further programs and related activities, available to all persons regardless of race, color, age, sex, handicap or
national origin. Information about alternate formats is available from Educational Media and Services, University of Florida, PO Box 110810,
Gainesville, FL 32611-0810. This information was published March 1998 as Bulletin (Tech.) 903, Florida Agricultural Experiment Station.
ISSN 0096-607X




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Last updated October 10, 2010 - - mvs