climate play an important role in the disease developement in plant. the effects of changes in temperature, CO2 and ozone concentrations, precipitation, and drought on the biology of pathogens and their ability to infect plants and survive in natural and agricultural environments. The climate influences the incidence as well as temporal and spatial distribution of plant diseases. Climate affects all life stages of the pathogen and host and clearly poses a challenge to many pathosystems.

1. WELCOME……..

2. CREDIT SEMINAR
ON
IMPACT OF CLIMATE CHANGE ON DISEASE DEVELOPMENT AND MANAGEMENT
PRESENTED BY
PRAKASH MANI KUMAR
(DEPARTMENT OF PLANT
PATHOLOGY)
(M/PP/94/2016-17)

3. SEMINAR CONTENT AT A GLANCE
1. INTRODUCTION
2. CAUSE OF CLIMATE CHANGE
3. FORM OF CLIMATE CHANGE
4. PLANT DISEASES AND CLIMATE CHANGE
5. CLIMATE CHANGE AND IT’S IMPACT ON HOST
PLANT AND PATHOGEN
6. IMPACT ON PLANT DISEASE MANAGEMENT
7. RESPONSE TO CLIMATE CHANGE
8. CONCLUSION

4. 1.INTRODUCTION
First of all, you should know that
weather and climate
are not same

5. WEATHER is what’s
happening outside
your window right
now.
WEATHER
• Short term
• Limited area
• Can change rapidly
• Difficult to predict

6. CLIMATE is the average of
many years of weather
observation.
• Long term
• Wide area
• Seasonal changes
• Measured over
long spans of time
CLIMATE

7. Climate Change.?
It refers to a change of climate that is attributed directly or
indirectly by human activity that alters the composition of the
global atmosphere and climate variability observed over
comparable time periods.
Climate encompasses the long-run pattern of numerous
meteorological factors (e.g. temperature, humidity, atmospheric
pressure, wind, rainfall, sunshine etc.) in a given location or
larger region.
(Gutierrez et al 2010)
Any change in climate over time, whether due to natural
variability or as a result of human activity.
(IPCC, 2007)

8. Climate change affects our agriculture due to 0.85°C average global
increase in temperature in last 100 years (IPCC & NASA’s Goddard
institute)
atmospheric CO₂ concentration increase from 280ppm 1750 to
409.76ppm in 2017.

10. Such changes will have a drastic effect on the growth and
cultivation of different crops.
Simultaneously, these changes will also affect the reproduction ,
spread and severity of many plant pathogens.

11. 2.CAUSES OF CLIMATE CHANGE
A. Natural cause (by nature)
B. Anthropogenic cause (man made)

12. A. Natural cause (by nature)
a. Continental drift b. volcanoes

13. Earth orbital changes
More tilt = warmer summers &
colder winters
Less tilt = cooler summers &
milder winters
c. Earth tilt

14. d. Ocean current
f. tsunami
e. Solar radiation
g. tornado
h. Forest fire

15. B. Anthropogenic cause (by man made)
a. Green house gases b. deforestation
c. Cole mining d. urbanization

16. GREEN HOUSE GASES
A portion of the radiation reaching to earth’s
surface which is scattered or reflected by clouds,
aerosols, dust and other particles.
Radiation reaching the planet is partially
absorbed, causing the earth to emit thermal
radiation and part of the radiation is reflected
back to the atmosphere.
Water vapour and radioactively active CO2 CH4
N2O and O3 etc. partially trap the reflected
radiation to warm the surface temperature, a
natural phenomenon known as the “GREEN HOUSE
EFFECT”.

18. PER CAPITA EMISSION OF GREEN HOUSE GASES
(Nair et al., 2013)

19. Global Average Abundances of Major, Long-Lived Greenhouse Gases

20. 3. FORMS OF CLIMATE CHANGE
Indian drought -2014
due to El nino effect
Cloud burst
(Uttarkhand)
Hud-Hud
Forest fire
in russia-2010

21. 4. PLANT DISEASE AND CLIMATE CHANGE

22. How climate change affect plant diseases.?

23. ENVIRONMENTAL FACTORS AFFECTING DISEASE DEVELOPMENT
TEMPERATURE
Temperature play an important role in growth and development of plant as well as
animal.
Each pathogen has an optimum temperature for growth. In addition, different growth
stages of the fungus, such as the production of spores, their germination, and the
growth of the mycelium.
RELATIVE HUMIDITY
Relative humidity is very critical in fungal spore germination.
High humidity favours development of the great majority of leaf and fruit diseases
caused by fungi and bacteria.
SOIL MOISTURE:
High or low soil moisture may be a limiting factor in the development of certain root
rot diseases.
High soil moisture level favour development of destrictive water mold fungi such as
species of Aphanomyces, Pythium and Phytophthora.

24. ELEVATED CO2
 Affect physiology of host pathogen interaction
 Increase in canopy density (> foliar diseases)
 Increase in moisture stress (> dry root rot)
 Increase in severity/fecundity (> anthracnose)
ELEVATED CO2
 Increased host susceptibility
 More rapid/new development of pathogen
 More rapid vector developement
 Increased over summering/overwintering of pathogen/vector
 Increased pathogen transmission
 New diseases/minor diseases can be become major
Eg- false smut of rice.
 Virulent forms of pathogen.

25. 5. CLIMATE CHANGE AND IT’S IMPACT ON
HOST PLANT AND PATHOGEN

26. IMPACT ON PLANT

27. ELEVATED CO2
It increase the photosynthesis and water use
efficiency of plant by that many foliar
pathogens benefit from denser plan growth
resulting more humid microclimate.
It favours the pathogen to intaeract with the
hosts.

28. When temperature increases plant show following
symptoms such as;
wilting
Leaf burn
Leaf folding
abscission
Physiological response
ELEVATED TEMPERATURE

29.  Change the structure of leaf surface
 Altering the physical topography &
 The chemical composition of surface, including the
structure of epicuticular wax.
 The negative effects of elevated O3 on plant physiology,
growth and yield are primarily linked to decreased
photosynthetic capacity caused by damage to the
photosynthetic biochemical machinery that result in visible
lesions, decreased leaf longevity and premature leaf
senescence.
(Sandermann, 1996; Reichenauer et al., 1998; Miller et al.,
1999; Long& Naidu, 2002; Morgan et al., 2004).
ELEVATED O3

31. IMPACT ON PATHOGEN

32. EFFECT OF INCREASED CO2 CONCENTRATION ON PATHOGENS
Concentration of carbohydrates in the host tissue
promotes the development of biotrophic fungi such as
rust.
Chakraborty et al. (2002)
high CO2 concentration reduced stomatal density and
the reduction in stomatal opening can inhibit
stomata-invading pathogens, such as rusts, downy
mildews.
Manning & Tiedemann (1995)
Elevated levels of CO2 can directly affect the growth of
pathogens.
Chakraborty et al. (2002)

33. Some recent studies assessing the effects of elevated
atmospheric CO2 on plant pathosystems
EFFECT ON DISEASE
SEVERITY/DISEASE
SYSTEM
EFFECT ON HOST REFERENCES
RICE BLAST Lower silicon concentration in
leaf tissues under elevated CO2
Kobayashi et al., 2006
SHEATH BLIGHT OF RICE Increased no. of tillers per plant
under elevated CO2
Kobayashi et al., 2006
LATE BLIGHT OF POTATO No effect on plant growth or
canopy structure, increased
levels of β-1-3-Glucanases
Plessl et al., 2007
BROWN SPOT OF
SOYABEAN
Increased plant height and
cropping density
Eastburn et al., 2010

34. EFFECT ON DISEASE
SEVERITY/DISEASE
SYSTEM
EFFECT ON HOST REFERENCES
INCIDENCE DOWNY
MILDEW OF SOYABEAN
No change in stomatal densities,
hypothesized changes in gs,
some changes in cuticular wax
structure
Eastburn et al., 2010
CROWN ROT OF WHEAT Increased plant biomass under
elevated CO2
Melloy et al., 2010

37. EFFECT OF ELEVATED O3 CONCENTRATION
EFFECT ON DISEASE
SEVERITY/DISEASE
SYSTEM
EFFECT ON HOST REFERENCES
DOWNY MILDEW OF
SOYABEAN
Lower canopy density, reduced
plant height, possible reduction
in gs
Eastburn et al., 2010
SOYABEAN MOSAIC Increased expression of defence
genes induced a non specific
transient defence response
against soybean mosaic virus
Bilgin et al., 2008
LATE BLIGHT OF POTATO Increased starch in leaves and
reduced starch in tubers
Plessl et al., 2007
BROWN SPOT OF
SOYABEAN
Decreased plant height and
reduced cropping density but no
effect on disease developement
Eastburn et al., 2010

38. EFFECT OF INCREASED TEMPERATURE
Changes in temperature and precipitation alter the
growth stage, development rate and pathogenicity
of infectious agents,
Chakraborty, S. et al.,(1998)
Climate change is also reported to cause a shift in
the geographical distribution of host pathogens.
Mboup, M et al, (2012)

39. EFFECT OF CHANGE MOISTURE
 Some pathogens such as apple scab, late blight and
several vegetable root pathogens are more likely to infect
plants with increased moisture content.
 Other pathogen like the powdery mildew species tend to
thrive under conditions with lower (but not low) moisture.
Coakley et al., (1999)
 Drought stress has been found to affect the incidence
and severity of viruses such as Maize dwarf mosaic virus
and Beet yellow virus
Clover et al., (1999)
 Early outbreak or increase in the intensity of potato late
blight under climate change in central Europe
Kocmankova et al., (2009)

40. 6. IMPACT ON PLANT DISEASE
MANAGEMENT

41. HOST RESISTANCE
 Cultivar resistance to pathogens may become
less effective because of increased static and
dynamic defences from changes in physiology,
nutritional status, and water availability .
 In case of soil born Sclerotium rolfsii infesting
groundnut, it has been observed that at 35°C
resistance variety breakdown and show
susceptibility.
Mayee (1996)

42.  The durability of resistance may be threatened
by number of infection cycle of pathogen within a
growing season increased because;
 Increase fecundity
 More pathogen generation per season
 Microclimate are more sustainable for disease
development. This may leads to more aggressiveness
of the pathogen races.
Cockley et al., (1999)
 Foliar pathogens have lower infection under
drought situation, due to lack of required leaf
wetness for spore germination.
Chowdappa (2010)

43. CHEMICAL CONTROL
 Chemical control may largely affected by climate
change in two ways;
 Changes in temperature
 Precipitation
 It may alter the dynamics of fungicide residue on
the foliage of crop
 Morphological and physiological changes in plant
resulting from growth under elevated CO2 could
affect the up take, translocation and metabolism
of systemic fungicides.

44. QUARANTINE AND EXCLUSION
 Management of climate change will put an
additional pressure on those agencies which are
responsible for exclusion as a plant disease
control strategy.
 Use of geographical information systems and
climate matching tools may assist quarantine
agencies in determining the threat posed by a
given pathogen under current and future
climates.

45. 7. RESPONSE TO CLIMATE CHANGE

46.  Multifactor studies of climate change effects.
 Long-term, large-scale records of pathogen and host
distributions.
 Integrated studies of host and pathogen responses, as well as
communities of soil and plant associated microbes.
 Better understanding of gene expression in plants and
pathogens in response to climatic factors.
 The efficacy of plant protection chemicals may change due to
unpredicated frequent rainfal.
 The effictiveness of bio control agent reduced under climate
change.
 Resistence of a crop variety may break due to development of
new virulent race of pathogens.

47. 8. CONCLUSION

48. Future prediction, relocation of crops and their diseases and
impacts will be felt in economic terms from crop loss.
Changes in level of CO₂ and O₃, influence disease by modifying
host physiology and resistance.
Changes in temperature and precipitation, influence disease
epidemiology.
Survival, longitivity and aggressiveness , increased with passage
of time due to change in climatic condition.
Best management will be from exclusion or early detection and
elimination wherever it is possible.
The establishment of FACE experiments has allowed plant
scientists to study host–pathogen systems.

49. Remember, we have only one EARTH…