© Benaki Phytopathological Institute
Si increases plant resistance to pathogenic fungi
5
ecium roseum
. Potassium silicate solutions
(pH 5.5 and 10.5) applied to bean plants
reduced the intensity of angular leaf spot
(
Pseudocercospora griseola
) by 42 and 30%,
respectively (Rodrigues
et al.,
2010). Supply
of silicon to wheat plants reduced the sever-
ity of spot blotch caused by
Bipolaris soroki-
niana
(Domiciano
et al.,
2010). Regarding the
wheat–
Pyricularia oryzae
interaction, Xavi-
er
et al.
(2011) demonstrated that supply of
silicon to plants decreased the area under
the blast progress curve and the number
of lesions per cm
2
of leaf area. Application
of 2mM silicon solution decreased the area
under brown spot progress curve and the
number of brown epidermal cells caused by
Bipolaris oryzae
on rice plants (Dallagnol
et
al.,
2011). Kablan
et al.
(2012) showed that so-
dium metasilicate added to banana plants
at a concentration of 1.7 mM reduced the
severity of the disease caused by
Mycospha-
erella fijiensis
(black sigatoka). Soybean
plants supplied with soluble silicon exhibit-
ed a near absence of symptoms of Asian rust
caused by
Phakopsora pachyrhizi
(Arsenault-
Labrecque
et al.,
2012). The efficacy of silicon
applied at 0.5 and 1.0 l/ha in controlling ap-
ple scab (
Venturia inaequalis
) on leaves and
fruit ranged from 67 to 81% and from 78 to
80%, respectively (Meszka and Wilk, 2014).
Foliar sprays with 2 mM potassium silicate
applied to common bean plants reduced
the severity of the disease caused by
Col-
letotrichum lindemuthianum
(anthracnose)
by 34% (Polanco
et al.,
2014). Regarding
the perennial ryegrass–
Magnaporthe oryz-
ae
pathosystem, Rahman
et al.
(2015) found
that calcium silicate applied at the rate of 5
metric ton/ha suppressed significantly gray
leaf spot in plants achieving a reduction in
disease incidence and severity by 39.5 and
47.3%, respectively. Application of 2 mM sil-
icon reduced the severity of blast disease
(
Pyricularia oryzae
)
in rice plants (Domicia-
no
et al.,
2015). Silicon treatment of soybean
was highly associated with increased plant
resistance to target spot caused by
Coryne-
spora cassiicola (
Fortunato
et al.,
2015). Root
application of silicon was more effective
compared to foliar application in reducing
the severity of powdery mildew (
Podospha-
era xanthii
) on melon (Dallagnol
et al.,
2015).
A number of studies have indicated that
silicon application can also reduce the se-
verity of soil-borne fungal diseases. For ex-
ample, potassium silicate at a concentration
of 1.7mM amended to nutrient solutions
of cucumber plants significantly reduced
the incidence of
Pythium ultimum
and
P.
aphanidermatum
, the causal agents of root
rot (Cherif
et al.,
1992). The application of po-
tassic and siliceous fertilizers increased resis-
tance of corn to stalk rot caused by
Pythium
aphanidermatum
,
Fusarium graminearum
(syn.
Gibberella zeae
) and
F. moniliforme
(syn.
G. fujikuroi
) (Sun
et al.,
1994). Soil silicon fer-
tilization applied to wheat plants reduced
severity of brown foot rot
(
Fusarium culmo-
rum
) and eyespot
(
Oculimacula yallundae
),
under high disease pressure (Rodgers-Gray
and Shaw, 2004). Application of 100 and 200
mM sodium silicate solutions decreased the
diameter of dry rot (
Fusarium sulphureum
)
lesions in potato tubers by 44 and 45%, re-
spectively (Li
et al.,
2009). Regarding the
belle pepper–
Phytophthora capsici
patho-
system, French-Monar
et al.,
(2010) reported
that supply of silicon to plant roots can po-
tentially reduce the severity of Phytophtho-
ra blight while enhancing plant growth.
Huang
et al.
(2011) showed that foliar appli-
cation of silicon at the dose of 100 mg Si/l to
tomato plants significantly reduced the se-
verity of Fusarium crown and root rot (
Fusar-
ium oxysporum
f.sp.
radicis-lycopersici
); data
suggested that the decrease in disease se-
verity was probably due to a delay in the on-
set of the initial infection of roots and the
movement of the pathogen from roots to
stems (Huang
et al.,
2011). Silicon amend-
ed to soil at a rate of 0.39 g/kg soil reduced
the symptoms of Fusarium wilt caused by
Fusarium oxysporum
f. sp.
cubense
on ba-
nana plants (Fortunato
et al.,
2012). Zhang
et
al.
(2013) demonstrated that application of
1.5 mM silicon improved resistance of rice to
sheath blight (
Rhizoctonia solani
). Moreover,
silicon solution at a concentration of 2 mM
decreased the area under relative lesion ex-
pansion progress curve of sheath blight (
R.
