Agriculture Reference
In-Depth Information
These new approaches offer new alterna-
tives for controlling PPN, which may be particu-
larly useful with nematode populations that
exhibit high intraspecific diversity (e.g.
G. pallida
),
or where the target is a broader spectrum of
nematode species. However, food web soil ana-
lysis and extensive food toxicological experiments
are needed before these genetically modified (GM)
approaches receive approval. The possibility of
gene flow to wild relatives in the main center of
biodiversity for potato is a barrier for their use in
certain situations. The use of the male sterile cul-
tivar Revolucion, engineered to provide nematode
resistance, could eliminate the possibility of this
route of gene flow (Celis
et al
., 2004). The ap-
pearance of nematode resistance and the effects
on other non-target organisms must also be
examined.
maximum yield, soil type, population levels at
planting, and the possibility of some nemati-
cide treatment in order to obtain an acceptable
potato yield and satisfactory nematode popula-
tion control. Both programs are available under
license. These programs were developed for specific
scenarios and geographic locations, so they
require validation for their application in differ-
ent agricultural and climatic conditions.
IPM in plant parasitic nematodes
The definition of this strategy is encompassed in
the definition by the University of California:
A pest management strategy that focuses on
long-term prevention or suppression of pest
problems through a combination of
techniques such as encouraging biological
control, use of resistant varieties, and
adoption of alternate cultural practices such
as modification of irrigation or pruning to
make the habitat less conducive to pest
development. Pesticides are used only when
careful monitoring indicates they are needed
according to pre-established guidelines,
treatment thresholds, or to prevent pests from
significantly interfering with the purposes for
which plants are being grown.
Models for population dynamics
and yield losses
The ability to predict the losses expected from
a given nematode population is essential in
making management decisions (Barker
et al
.,
1985). Practical models have been included in
programs to help growers and crop managers
to decide on the use of chemicals, crop rotation,
and how other factors such as the type of soil,
the initial soil nematode inoculum, and potato
cultivar will affect yield and population dynamics.
The software-based nematode advisory system,
NemaDecidePlus
TM
(Been
et al
., 2005), is a pro-
gram that can compute scenarios for the
control of PCNs, the Columbia root-knot nema-
tode, the root-lesion nematode, and for mixed
infestations of all these nematodes. This pro-
gram takes into account whether the crop is
intended for seed, ware, or starch potatoes.
Decision support with mixed populations is
very interesting to predict the long-term effects
of management decisions and to anticipate fu-
ture management problems. Another program
of interest was developed by the Scottish Crop
Research Institute and financed by the British
Potato Council (UK), called “Integrated control
of potato cyst nematode (PCN)
Globodera palli-
da
, the white potato cyst nematode” (British Po-
tato Council, 2011). This program takes into
account the level of resistance or tolerance of
the cultivar used in the rotation, the estimated
Specifically for nematodes, each region with dif-
ferent ecological conditions and pests must have
its own IPM system in order to obtain the best
profit of all available actions.
The development of nematode integrated
management programs requires analysis of the
impact of each individual tool on a nematode
population, as well as the determination of cost-
benefit ratios for grower acceptance (Sikora
et al
.,
2005). From this perspective, measures to control
nematodes are not to eradicate but to control the
population under threshold damage levels, and
these measures must be economically viable.
Some tools used in IPM can be applied at differ-
ent times in a cropping cycle or in a rotation
sequence, and they have mainly been listed in
the points discussed above in this chapter. How-
ever, it is vital for sustainable management in
IPM that correct identification and quantifica-
tion is performed for the PPNs that could be a
risk for crop management.
