sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

SDU Faculty of Forestry Journal
Serial: A, Number: Special Issue, Year: 2009, ISSN: 1302-7085, Page: 71-84
INTERACTION BETWEEN Diplodia pinea, D. scrobiculata AND
SEVERAL FUNGAL ENDOPHYTES IN RED AND JACK PINE
SEEDLINGS
Oscar SANTAMARÍA 1 *; Denise R. SMITH 2 and Glen R. STANOSZ 2
1 Dpt. Ingeniería del Medio Agronómico y Forestal, Universidad de Extremadura. Ctra. de Cáceres
s/n, 06071 Badajoz, SPAIN.
2 Dpt. of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Dr., Madison 53706, WI,
USA.
ABSTRACT
* osantama@unex.es
Sphaeropsis sapinea sensu lato is a conifer fungal pathogen that causes mainly shoot
blight and stem cankers. Recently, the former S. sapinea has been divided in two new
species, D. pinea and D. scrobiculata. The aim of the study was to evaluate the interaction
between those two fungal pathogens and among them and several fungal endophytes
isolated from healthy shoots of Pinus resinosa and P. banksiana adult trees. Interaction was
evaluated by means of co-inoculations in Red and Jack pine seedling under greenhouse
conditions. Symptom severity (distance below the inoculation site at which necrotic needles
were observed) was recorded after four weeks of incubation and used as response variable.
The results showed D. pinea to be much more aggressive on both hosts than D.
scrobiculata. When both pathogens where inoculated in a single plant, the symptom
development was mainly due to D. pinea. Furthermore, D. scrobiculata showed antagonism
with D. pinea, since when both pathogens co-occurred in a single seedling, symptom
severity caused by D. pinea was lower than that caused when D. pinea acted alone. The
results also suggested that two of the endophytes, Trichoderma atroviride and Rosellinia
subiculata, were able to inhibit the pathogen spreading and therefore they could be
considered biocontrol agents against D. pinea. Further studies would be needed to confirm
biocontrol.
Keywords: Sphaeropsis sapinea, biocontrol, Pinus sp, inoculation.
1. INTRODUCTION
Sphaeropsis sapinea sensu lato is a conifer fungal pathogen of worldwide
distribution which has caused significant economic damage in nurseries,
plantations, and natural stands (Gibson, 1979; Nicholls and Ostry, 1990; Davison et
al., 1991). The parasite can infect most parts of host plants, causing a broad range
of disease symptoms: shoot blight, stem cankers, branch dieback, dead tops, death,
and blue staining of cut wood (Nicholls and Ostry, 1990; Stanosz and Cummings-
Carlson, 1996).
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