Agriculture Reference
In-Depth Information
are less effective at controlling this species than
G. rostochiensis
(Minnis
et al
., 2004).
Rotations that include a non-host crop for
RKNs, such as maize or wheat, will minimize
damage from some
Meloidogyne
spp. (Krishna
Prasad, 2008). However, some RKN species such
as
M. chitwoodi
can attack cereals and can sur-
vive in potato tubers stored for more than
2
years
at 1°C, and in tubers left in the field over winter
(Finley, 1981). Cereal rotations (
2-3
years) have
proven useful in the management of
D. destructor
in potato fields, despite their wide host range
(Kornobis and Stefan, 1991). Each strategy
must consider the specific attributes of the target
species, as well as rotation options.
Potato volunteers in the crop rotation or till-
age period must be taken into account for success-
ful nematode reduction, as well as the possible
weed hosts for particular species. TRV can be main-
tained by weeds in rotation of tillage; for example,
hairy nightshade (
Solanum sarrachoides
Sendtn.) in
rotation crops of lucerne or Scotch spearmint
(
Mentha
×
Gracillis
) (Boydston
et al
., 2008).
Green manure
Green manure amendments for the manage-
ment of PPNs and improving soil physical charac-
teristics, especially water infiltration and pene-
tration resistance, are currently being investigated.
Additionally, some green manures could be ap-
plied with other strategies, as nematicides, in
order to improve their efficacy. Sorghum sudan-
grass (
Sorghum bicolor
(L.) ×
Sorghum arundinace-
um
(Desv.) Stapf var. sudanense (Stapf) Hitchc.),
grown annually as a green manure in combin-
ation with poultry litter/tillage/fallow, has been
effective in the control of RKNs and lesion nema-
todes (Kratochvil
et al
., 2004). MacGuidwin
et al
. (2012) have demonstrated that green
manure amendments can be used to reduce
damage from
V. dahliae
and
P. penetrans
. Crop ro-
tation for
3
years, with poor or non-hosts of
M. chitwoodi
interspersed with green manure
amendments without nematicides, provided
nematode control comparable to soil fumigation
(Riga
et al
., 2003). Some more local manure
amendments such as wastes from the logging
and wood industries (freshly-crushed conifer bark
and sodium lignosulfonates) possess nematicidal
properties, and significant reduction of PCN
multiplication has been observed (Matveeva
et al
., 2010).
Early harvesting
Growing early-maturing potato varieties or har-
vesting tubers as soon as possible after allowing
for proper maturation may help in lowering the
severity of tuber damage by
Meloidogyne
spp
.
However,
M. chitwoodi
females continue to de-
velop within infected tubers in storage at lower
temperature, causing problems with the market-
ability of the crop (Santo, 1994). This strategy
must be based on nematode development rates,
which are determined from the accumulated
degrees above a basal development temperature
for each nematode species. However, this ap-
proach can lead to specific species selection if this
measurement is done routinely in fields with
mixed species, as has been shown with
G. pallida
(more favored) and
G. rostochiensis
(Webley and
Jones, 1981). Knowledge of the degree days re-
quired by the different PCN species to develop
through their life-cycle stages in each potato cul-
tivar could be used to plan the harvest time to
precede cyst development, and thereby minimize
population reproduction (Alonso
et al
., 2011).
Additionally, deep plowing and exposing soil to
summer heat could also diminish egg viability in-
side the cysts (Krishna Prasad, 2008), though
this is mainly applicable in warm climates.
Trap cropping
Solanum sisymbriifolium
Lamarck can be an ef-
fective trap crop with strong hatch stimulation
and total resistance to both
G. rostochiensis
and
G. pallida
(Scholte, 2000); nematodes do not
develop further than J3 (Sasaki-Crawley
et al
.,
2010). It can be plowed in as green manure.
However, this plant needs to accumulate a certain
level of dry matter to achieve sufficient control,
which restricts its use in cold climates (Hockland,
2010). Trap cropping using potato plants could
also be useful if the plants were incorporated
into the soil before nematodes reproduced (about
300 day degrees at a threshold of 4°C in
G. pallida
)
and using vigorous rooting potato varieties such
as Cara (Lane and Trudgill, 1999). However, the
timing, costs, and risks of this strategy must be
considered carefully. Other crops in more restricted
conditions (Andean region), such as
Lupinus mu-
tabilis
Sweet, oca (
oxalis tuberosa
Molina), isano
(
Tropaeolum tuberosum
Ruiz & Pav.), ollucus (
Ullucus
