Agriculture Reference
In-Depth Information
(a)
70
(b)
70
60
60
50
50
40
40
30
30
20
20
10
10
0
0
Control
Ethokem,
0.1%
Bond,
3%
Vapor
Gard, 3%
Control
Ethokem,
0.1%
Bond,
3%
Vapor
Gard, 3%
(c)
60
50
40
30
20
10
0
Control
Ethokem,
0.1%
Bond,
3%
Vapor
Gard, 3%
Figure 12.3
Effects of fi lm-forming polymers on (a) spore germination, (b) appressorium formation
and (c) haustorium formation. Bond and Vapor Gard treatments signifi cantly different from the control
at
P
< 0.01. Data taken from Sutherland & Walters (2002), with kind permission of Springer Science and
Business Media.
altered germling development on the leaf surface, reducing germination of conidia, as
well as the subsequent formation of appressoria and haustoria (Figure 12.3) (Sutherland &
Walters, 2002). However, the fi lm-forming polymers performed less well under fi eld
conditions. Thus, Bond used as a 3% spray reduced mildew infection by 63%, in compar-
ison with the commercial fungicide cyproconazole, which reduced mildew infection by
84% (Sutherland & Walters, 2002). In a study to determine whether fi lm-forming poly-
mers exerted a direct effect on fungal pathogens, Sutherland & Walters (2001) found that
Ethokem and Bond completely inhibited linear growth of
Pyricularia oryzae
when incor-
porated into the growth medium at 1% and 2%, and strongly inhibited linear growth
of
Pyrenophora avenae
at the same concentrations. Less of an effect on linear growth of
these fungi was obtained with Vapor Gard, although all three polymers decreased cell
lengths and led to gross changes in hyphal morphology, including swollen, shortened
