© Benaki Phytopathological Institute
Hellenic Plant Protection Journal
8:
46-54, 2015
DOI 10.1515/hppj-2015-0007
Department of Entomology and Agricultural Zoolo-
gy, Benaki Phytopathological Institute, 8 St. Delta Str.,
GR-145 61 Kifissia, Attica, Greece
* Corresponding author:
by plant’s fibers to complete their devel-
opment (Lock, 1965). In addition to the de-
structive activities of the larvae, the adults
are often natural vectors of plant pathogen-
ic bacteria, such as
Erwinia carotovora
(Dye)
(Aquino Bolanos
et al.,
2011). In Central and
South American agave cultivations chem-
ical insecticides are commonly applied to
control the sisal weevil, however there are
many problems and controversies connect-
ed to their use (Solis
et al.,
2001; Terán-Var-
gas
et al,
2012). Firstly, as the weevil com-
pletes its development within a protected
habitat, inside the agave leaves, insecticides
have a low effectiveness (Figueroa-Castro
et
al.
, 2013). Secondly, their extended applica-
tion harbors the risk of resistance develop-
ment in the pest species (Terán -Vargas
et
al.,
2012). Finally, there are certain restric-
tions in the use of synthetic insecticides in
urban landscape areas, where the weevil is
mainly found, due to their effects on the en-
vironment and health risks. Therefore, the
development of biological and biotechnical
control methods is of great environmental
and economic importance.
Although a few arthropod natural ene-
mies of the sisal weevil could potentially be
regarded as biological control agents in its
Pathogenicity of indigenous strains of three
entomopathogenic fungi to the sisal weevil,
Scyphophorus
acupunctatus
(Gyllenhal) (Coleoptera: Curculionidae)
V.T. Gkounti, D. Markoyiannaki
and D.Ch. Kontodimas*
Summary
The pathogenicity of indigenous isolates of
Beauveria bassiana
,
Metarhizium anisopliae
and
Isaria fumosorosea
was evaluated in the laboratory against larvae and adults of the sisal weevil,
Scyphophorus acupunctatus
. Inoculation was achieved via immersion of individuals into conidia sus-
pensions of different concentrations. All three fungal species proved high pathogenicity against lar-
vae of the weevil, causing 100% mortality in most of the treatments.
Beauveria bassiana
caused the
highest mortality of the adults (86.67±12%), followed by
M. anisopliae
(46.67±17.8%) and
I. fumosoro-
sea
(40±17.5%). Mean survival time also differed significantly among treatments and life stages of the
weevil. In total, larvae survived significantly fewer days than adults post infection. Results of the pres-
ent study indicate the potential of indigenous strains of entomopathogenic fungi as biological control
agents against the invasive weevil.
Additional keywords
: agave,
Beauveria bassiana
, Curculionidae,
Isaria fumosorosea, Metarhizium anisopliae
Introduction
The sisal weevil,
Scyphophorus acupuncta-
tus
(Gyllenhal), is amongst the most severe
pests of both cultivated and ornamental
agave plants (Pott, 1975; Valenzuela-Zapata,
1994; Camino Lavin
et al.,
2002). In its place
of origin, the Nearctic region, it has been
found to cause severe economic losses by
strongly damaging
Agave tequilana
(We-
ber) the tequila producing agave (Solis
et
al.,
2001). The sisal weevil was introduced
in Europe around 1980, when it was first re-
corded on imported
Yucca
sp. in the Neth-
erlands (van Rossem
et al.,
1981). Since then
it has been found in many European coun-
tries (i.e. Italy, France, Greece) on ornamen-
tal plants (Colombo, 2000; EPPO 2008; Kon-
todimas and Kallinikou, 2010).
The females use the basal parts of the
agave leaves for feeding and as oviposition
sites. Furthermore, once the neonate lar-
vae hatch they start to bore galleries with-
in the plant’s head and form a cocoon made
