Agriculture Reference
In-Depth Information
Similarly, seed potato tubers are stored for at
least 6 months before they are shipped for plant-
ing (Olsen, 2010; Frost
et al
., 2013). Therefore,
good storage conditions are essential to main-
tain the quality and health of potatoes, which
can be compromised by disease development
(Secor and Gudmestad, 1999).
Sustainable agriculture practices have been
developed over millennia of food and fiber pro-
duction. Practices for managing pests and
diseases include changing plant and crop archi-
tecture, burning, adjusting crop density, depth
or time of planting, planting at increased eleva-
tion, planting diverse crops, fallowing, flooding,
mulching, multiple cropping, planting without
tillage, using organic amendments, planting in
raised beds, rotation, sanitation, and manipulat-
ing shade (Thurston, 2004). Potatoes, like many
other crops, have been grown for food for at least
8000 years, and several of the practices men-
tioned were used to avoid outbreaks of disease.
Modern potato production in North America
and Europe demands uniformity in quality and
economic return for the grower and the proces-
sor. Recent trends suggest the use of potatoes
has shifted from consumption of table-stock po-
tatoes to processed potato products (Pavlista and
Feuz, 2005; Loy
et al
., 2011). However, in devel-
oping economies the emphasis is often on in-
creasing or maintaining yield where there are
limitations to nutritional inputs and rotational
options and certified seed (Allemann
et al.
, 2004;
Scott, 2011). In both developed and developing
economies, the basic objectives for potato pro-
duction include system stability, resilience, pre-
dictable productivity, and efficiency (Johnson
and Rowe, 2007). However, several diseases an-
nually threaten these goals. For example, potato
late blight caused by the oomycete,
Phytophthora
infestans
(Mont. De Bary), initiated devastating
losses across Europe and New England, USA, in
the mid-19th century (Turner, 2005), and con-
tinues to threaten production even into the 21st
century (Fry, 2008; Hu
et al
., 2012).
Historically, most potato pathogens have
likely been transported within and between
countries during the course of trade over time.
More recently, the impact of climate change has
had a number of observed, anticipated, or pos-
sible consequences on crop health worldwide, as
discussed in several reviews (Hijmans
et al
.,
2000; Sparks
et al
., 2008, 2010; Haverkort
et al
., 2009; Garrett
et al
., 2011; Savary
et al
.,
2011; Sturrock
et al
., 2011). Global population
increase and changes in sources of supply and
demand for natural and processed food products
from local to global (Padgham, 2009; Von
Braun, 2009) enforce further pressures on the
distribution of diseases of all crops, including
the potato crop. The interaction between global
population dynamics and climate change may
have far-reaching effects on plant and potato
health in the future (Savary
et al
., 2011). These
factors could have interacted already, as mani-
fested by the recent appearance of the disease,
zebra chip, caused by
Candidatus
Liberibacter
solanacearum, which is vectored by the potato
psyllid (
Bactericera cockerelli
(Hemiptera: Triozidae)),
and has impacted potato production inter-
nationally (Crosslin
et al
., 2011, 2012; Munyan-
eza
et al
., 2011; Pitman
et al
., 2011; Buchman
et al
., 2012).
According to the American Phytopatho-
logical Society publication,
Compendium of Potato
Diseases
, 2nd edition, there are
35
economically
important bacterial, fungal, and oomycete
pathogens of potato worldwide (Stevenson
et al
.,
2001). The most common and serious bacterial,
oomycete and fungal pathogens of potatoes
worldwide are profiled in
Table 11.1
.
The object-
ives of this chapter are to describe how some of
the main potato diseases affect production and
markets, how the diseases perpetuate and dis-
seminate, and to discuss control strategies and
prospects for the future.
11.1 Survival and Spread
of Potato Diseases
Seed health management
As in all crops, the occurrence of any disease in
the potato crop is a function of the interaction of
host, pathogen, and the environment. Shifts in
production techniques, such as importing seed
from new international sources, may lead to the
appearance of non-indigenous diseases. Short-
ening of rotation intervals between crops may
favor the build up of soilborne inoculum of tuber
pathogens, leading to a crop health status that
requires the development of new management
options. In extreme cases, if a new pathogen is
