Agriculture Reference
In-Depth Information
10.4
PHYTOPATHOGENS: INDICATOR OF CLIMATE CHANGE
A living system always responds to a stimulus. Being a living system the
phytopathosystems react to climate deviation. Plant pathogens following
very unique life history exhibit a wide range of reaction to climate change.
For example, latent infection is found in viral pathosystem and expression
of symptom depends on thermo-change (DeBokx and Piron, 1977), there-
fore, detection of such pathogen is varied according to climate. Likewise,
fungal pathogens are completely dependent on RH or dew point, tempera-
ture associated with other factors for the infection in plant tissue (Huber
and Gillespie, 1992). This means shift in disease risk is totally governed
by changes in these environmental factors (Vanderplank, 1963).
Similar trend may be seen for pathogen populace with wide range of
genetic variability, which often creates complication plant disease man-
agement (Strange, 2005). Adaptation toward pesticide and develop resis-
tance is a major problem and a part of evolution of the phytopathogens
(Agrios, 2005). Likewise, the pathogen species may rapidly adapt to cli-
mate change, however, this depends on the kind of pathogen (McDonald,
2002). Thus, anticipation for best time of management tactics is difficult
to apply against potential pathogen population under climate change sce-
nario. Other effect of climate change is activation of weaker pathogen and
qualifies them to be economically important, for example, Rhizoctonia
solani in rice ( Fig. 10.1 ). The long-distance dispersal through wind (e.g.,
Ustilago scitaminea , P. infestans ) and water (e.g., X. oryzae , members of
order peronosporales) is a part of such changes that create epidemic in new
areas for an exotic spp. (Chakraborty et al., 2008).
10.5 FUNGAL PHYTOPATHOSYSTEMS INFLUENCED BY
CLIMATE CHANGE
10.5.1 PUCCINIA STRIIFORMIS F. SP. TRITICI
The stripe rust pathogen ( P. striiformis f. sp. tritici ) has been recognized
as a cool climate favoring pathogen. Recently, the isolates collected after
2000 have shown their increased aggressiveness (e.g., shorter latent pe-
riod) under higher temperature regime (Milus et al., 2009). The new iden-
tified race caused severe losses during 2001 to 2003 in the central United
States (Chen, 2005).
 
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