2 research outputs found
Pathogenicity of the root-knot nematode Meloidogyne javanica on potato
Host–parasite relationships and pathogenicity of
Meloidogyne javanica
on potatoes (newly recorded from Malta) were
studied under glasshouse and natural conditions. Potato cvs Cara and Spunta showed a typical susceptible reaction to
M. javanica
under natural and artificial infections, respectively. In potato tubers,
M. javanica
induced feeding sites that
consisted of three to four hypertrophied giant cells per adult female. Infection of feeder roots by the nematode resulted
in mature large galls which usually contained at least one mature female and egg mass. In both tubers and roots, feeding
sites were characterized by giant cells containing granular cytoplasm and many hypertrophied nuclei. Cytoplasm in giant
cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship
between initial nematode population density (
P
) [0–64 eggs + second-stage juveniles (J2s) per cm
3
soil] and growth of
cv. Spunta potato seedlings was tested under glasshouse conditions. A Seinhorst model [
y = m
+ (1
−
m
)
z
(
P
−
T
)
] was fitted
to fresh shoot weight and shoot height data of nematode-inoculated and control plants. Tolerance limits (
T
) for fresh
shoot weight and shoot height of cv. Spunta plants infected with
M. javanica
were 0·50 and 0·64 eggs + J2s per cm
3
soil,
respectively. The
m
parameter in that model (i.e. the minimum possible
y
-values) for fresh shoot weight and shoot height
were 0·60 and 0·20, respectively, at
P
= 64 eggs + J2s per cm
3
soil. Root galling was proportional to the initial nematode
population density. Maximum nematode reproduction rate was 51·2 at a moderate initial population density (
P
= 4
eggs + J2s per cm
3
soil).peer-reviewe