The fungus
Fusarium circinatum
Nirenberg & O'Donnell causes pine pitch canker, an important disease for conifers
worldwide.
F. circinatum was first detected in Chile in 2001 and to date is present in nurseries and clonal hedges from
Libertador General Bernardo O'Higgins Region to Los Ríos Region. The purpose of this study was to evaluate the potential
of
Trichoderma spp.
and
Clonostachys spp.
strains to control
F. circinatum in
Pinus radiata
D. Don seedlings in the
absence of other effective control methods. Eighty-one
Trichoderma spp. and
Clonostachys spp. strains were evaluated
through
in vitro assays to determine their ability to act as antagonists of
F. circinatum and 21 strains were tested for their
ability to reduce post-emergence mortality and increase
P. radiata survival under greenhouse conditions. During
in vitro
experiments, 15 strains of
Trichoderma inhibited mycelial growth of the pathogen by more than 60% and one strain of
Clonostachys showed parasitism of
F. circinatum hyphae. Greenhouse experiments showed no control of the disease when
the antagonists were added to substrate after the pathogen. However, when the antagonists were added before the pathogen,
four strains (
Clonostachys UDC-32 and UDC-222 and
Trichoderma UDC-23 and UDC-408) reduced post-emergence
mortality between 80 and 100%. Among these strains, only
Clonostachys UDC-222 significantly increased the survival of
P. radiata seedlings. These results showed that
Clonostachys UDC-222 has the potential to be used as a biocontrol agent
against
F. circinatum in the production of
P. radiata plants.