Impacts of climate change on IPM and how the Farm Bill should encompass it
National IPM meetings, Oct. 4, 2011
Mike Hoffmann
Associate Dean, College of Agriculture and Life Sciences
Director, Cornell University Agricultural Experiment Station
Cornell University
Ithaca, NY
Background notes used for brief overview of topic
Climate change ----- The facts – the science
o Climate vs. weather – it is important to understand the difference
Weather is the atmospheric condition (e.g., temperature, precipitation,
humidity, wind) at any given time or place. In most places, weather is highly
variable and can change from hour to hour, day to day, and season to season. In
contrast, climate refers to long-term “weather averages” such as the average
number of heat waves per year over several decades. The World Meteorological
Organization considers the statistical mean and variability of factors such as
temperature and precipitation over a period of three decades to evaluate
climate trends, but climate can refer to other periods of time, sometimes
thousands of years, depending on the purpose.
The basics about climate change
 Greenhouse gases absorb infrared radiation (Tyndall 1863)
o Sun emits mainly short wave radiation: most of sun’s energy gets through
the atmosphere, but earth’s surface emits infrared radiation
(heat). Hence greenhouse gases keep the heat in.
o Without CO2 - earth would be very cold, with too much, very hot
 Fossil fuel signature
o 3 isotopes of carbon: 14C, 13C and 12C (12C preferred by plants)
o Burning of fossil fuels (ancient plants) releases 12C into the atmosphere
o 12C now highest in past 10,000 years, with biggest increase since 1850’s
o Evidence from ice cores, tree rings
o Direct link to human activity
 Mauna Loa Record 1958-present – CO2 has increased 318-390 ppm
 1850’s to present CO2 has increased from 270 ppm to 390 ppm today
 Along with other greenhouse gases

Global temperatures are increasing
o 1.50F increase globally (warmer at poles)
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 Alaska 70F, Antarctica 100F
Hottest decade ever globally: 2000-2009
Warming very fast (100X faster then since last ice age)
o Global average temperatures will increase 8-100F by 2100 (if we continue
with business as usual)
 Temperature data based on 5,000 land based stations, 1000
buoys, ships
o Data from satellites – indicates a cooling upper atmosphere and a cooling
lower atmosphere, a consistent message

And its not just average temperatures
o Sea level rise is occurring due to glacial melt, thermal expansion of water
(oceans)
o Acidification of oceans – 30% increase since late 1800’s
o Extreme weather events – more heat, more moisture, events increasing
o Glaciers melting - worldwide
o Greenland ice – about 50 cubic miles loss/year
o Arctic sea ice retreating – artic will be ice free in few decades, well ahead
of earlier predictions
o Plant hardiness zones moving north
o Pines in Rocky’s – 50 -70,000 square miles experiencing death of pines
due to extended drought and warmer temperature permitting bark
beetle populations to reach extreme densities.
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We face a grand challenge, a different challenge
Agriculture will not be business as usual

Impacts on IPM
o Increasing CO2 levels
o Increasing temperatures
o Increase in weather variability
o Impacts will not be uniform – across US, globe
 Changes in precipitation patterns
o Multitude of direct and indirect impacts on pests, and interactions among
pests, natural enemies and crops
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
IPM will not be business as usual
Weeds
o Weeds generally favored by increasing CO2 levels
o Poison Ivy growth greatly accelerated under higher CO2 levels
o Increasing temps mean expansion of weeds into higher altitudes,
latitudes
o Impact on weed control with herbicides - examples
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Increase in severe weather – heavy rains to droughts
Drought can increase cuticle thickness and increased leaf
pubescence, thus reduced effectiveness of herbicides
Herbicides generally less effective when plants exposed to higher
CO2 levels, e.g., glysophate
Interactions with herbivores (biological control) agents likely to
change

Arthropod pests
o Increase in CO2 levels results in
 Increasing
 Food consumption by larvae (plants may be less nutritious)
 Reproduction in aphids
 Predation by some predators
 Effects of foliar applications of BT – pests eat more leaf
area, eat more Bt – increased effect
 Decreasing
 Insect developmental rates
 Response to alarm pheromones by aphids
 Parasitism
 Nitrogen based plant defenses
o Increase in temperatures
 General consensus – with warmer temperatures – a great
diversity of arthropod pests and higher populations
 Increased summer temperatures – faster growth, more
generations per year, more risk of damage (feeding rates)
 May in part be countered by faster plant growth?
 Range expansion –northward, upward range expansion – crop
and human pests -- dengue and malaria will likely increase
 The development of the dengue virus inside the mosquito
also shortens with higher temperatures, increasing the
proportion of mosquitoes that become infectious at a
given time.
o Soil conditions – extreme wet to extreme dry will affect stages
developing in soil
o Biological control - Out of synchrony
 Hosts emerge first, avoid parasitoids, predators

Plant diseases
o The plant disease triangle – host, pathogen, environment, will all be
affected by increasing temperatures, changes in humidity, CO2 levels
o Not simple, some crops become more susceptible, some less susceptible
to disease with increasing temperatures
o Warmer winters will permit higher levels of survival by some pathogens,
and allow northward expansion of some
o Warmer and moisture conditions likely to increase incidences of fungal
pathogens, leaf wetness will vary more
o High or low moisture conditions in the soil – enhance or decrease levels
of infection
o Increased CO2 levels can increase or decrease severity of plant disease –
 With higher CO2 growth rates of plants may be faster, closing the
canopy sooner – improving conditions for pathogen
 Higher CO2 can increase levels of fungal spore production
 Higher CO2 can result in changes in the plant increasing resistance
to pathogen
o Fungicide efficacy may change with increased levels of CO2, moisture,
temperature
o Increased incidence of storms may require more applications
o Unknown changes in interactions with antagonistic organisms
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Impacts on IPM
o Greater challenges
o More variation in weather, more difficult to predict, more difficult to
control pests
o Overall more risks – from insects, weeds, pathogens
o Use of pesticides more challenging, more frequent rain, higher
temperatures
o More inputs – pesticides
o Reliability of existing threshold levels
 Because of changes in feeding rates – will today’s insect/plant
threshold hold in the future?
 Reliance on natural enemies may change – out of sync, less
benefit from fungal pathogens
o Need better communication to producers – with changes in IPM
approaches
o More multidisciplinary approaches needed
o We will need new cultivars, improved irrigation, soil drainage
o Major changes in IPM programs
o Need increased funding to deal with the combined effects of climate
change, but we are seeing cuts at both the state and federal level
•
Is this an opportunity to stress the importance of IPM?
o Need for IPM greater then ever.
o More risks to our food security, to human health
o But climate change is currently not a high priority in Washington
o Will it have a presence in the Farm Bill?
References and Additional Reading/Resources
Trumble and Butler. 2009. Climate change will exacerbate California's insect pest
problems. Cal Ag. 63:73-78
http://ucanr.org/repository/CAO/landingpage.cfm?article=ca.v063n02p73&fulltext=y
es
See California Agriculture Volume 63, Number 2 “Unequivocal” - How climate change
will transform California.
http://ucanr.org/repository/CAO/issue.cfm?volume=63&issue=2
Gregory, et al., 2009. Integrating pests and pathogens into the climate change/food
security debate. J. Experimental Biology 60:2827-2838.
http://jxb.oxfordjournals.org/content/60/10/2827.abstract
Wolfe et al., 2008. Projected change in climate thresholds in the Northeastern U.S.:
implications for crops, pests, livestock, and farmers. Mitig. Adapt. Strat Glob Change
13:555-575. http://www.springerlink.com/content/r40m6u08772131g2/
See also Overview of climate change impacts on agriculture
http://www.climateandfarming.org/clr-cc.php
For updates on climate science one option is
http://www.climateandfarming.org/clr-cc.php