GLOBAL WARMING/CLIMATE CHANGE EFFECTS ON PESTS AND DISEASES OF POTATO AND OTHER CROPS

Gary Secor North Dakota State University

MY BELIEFS AS A SCIENTIST

• I believe there are forces of nature that are much more powerful than anything we as people can build or destroy or influence • Terremotos, maremotos, volcanes • These forces have a major impact on climate

• I am a believer in cycles of nature

• I believe that organisms g constantlyy evolve and change g and adapt to new circumstances and pressures • I believe that much of what is called climate change is only climate variability or changes in weather • Climate is long term – centuries and millennia • Weather is what we see out our window • Consequently I do not think that global warming due to climate change h iis as serious i as many people l ddo, bbutt I ddo bbelieve li iin climate variability

• Regardless g of our pposition on gglobal warming, g, we need to respond to this change, even if short term, and more importantly, the increase in population and food supply for the world • So I am pleased to share with you some examples of how climate change may affect pests and diseases of potato and some other crops, and some actions we can collectively do to be proactive to this change

• With this introduction,, I would like to show examples p of new and changing diseases and pests of potato and some other crops • It is arguable whether these new and changing pests and diseases are due to global warming, climate change climate variability or natural change and adaptation • You the audience all have your own opinion and can decide

EXAMPLES OF CHANGES THAT MAY BE OR COULD BE DUE TO CLIMATE CHANGES •

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New diseases •

Zebra chip

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Yellow decline of sugar beet

Changing diseases and pests •

Late blight

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Early blight

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Blackleg

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Tuber moth

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Orange wheat midge

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Rhizoctonia of sugarbeet

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Bacterial wilt

Potato growth

Zebra Chip

• Disease discovered in Mexico in 1994 • Has spread to southwestern US, Guatemala, Honduras, New Zealand (warm climates) • Caused by a new bacterium Liberibacter solanacearum; related to another new disease, citrus greening • Transmitted by a new vector; the potato/tomato psyllid (Paratrioza cockerelii) • Both the disease and the vector are spreading north in the US • Psyllids found in North Dakota for the first time in 2010 • Is this new disease the result of climate change? Will it come to Chile?

# 673

# 676

Sugar beet yellow decline # 676

• Yellow decline is caused byy a new species p of Fusarium;; not yyet named • There are many species of the Fusarium fungus • Found in 2005 in west central Minnesota; largest sugar beet growing area in the US • Causes yellowing, early death and severe internal discoloration of roots • Is I spreading di iin th the region i • The Fusarium fungus likes heat • Is this new disease related to warming conditions?

Late blight G. Secor

E Banks

E. Banks G. Secor

• Most important disease of potatoes worldwide, worldwide including Chile • Irish potato famine • Causes C rott off allll parts t off potato t t plant, l t iincluding l di ttubers b • Control by chemicals and plant resistance • Pathogen composed of many genotypes (strains) • In recent years the pathogen has changed and produced new genotypes • Europe since 2008; overcome variety resistance • US since i 2010 • New genotypes more aggressive and competitive • Are these new genotypes due to climate change? Will they come to Chile?

Early blight

• Foliar disease; can cause tuber blemish • This disease is increasing in in recent years in Europe and south Chile • Favored by warm conditions • Is pathogen changing? Is the change due to climate change?

Blackleg

Caused by a bacterium called Dickeya dianthicola Formerly o e y ca called ed Erwiniaa cchrysthanthemi ys a e Causes blackleg and stem rot of potato In Europe the predominate biovars were 1 and 7 Since 2000, biovar 3 has been almost exclusively found Biovar 3 has a higher growth temperature maximum Possibly due to increasing temperatures during the growing season • New species called Dickeya solani • Climate change?? Imported to Chile?? • • • • • • •

Potato tuber moth http://images.google.com/imgres?imgurl=http://www.insectscience.co.za/pictures

• Caused by Phthorimaea operculella • Occurs worldwide, including northern Chile • IIn the th US, US has h been b limited li it d to t potatoes t t grown in i warm climates • In recent years has moved north from California to new locations in Oregon and Washington • Is this due to increased temperatures in OR and WA? Could this pest move from northern Chile to southern Chile?

Orange wheat midge www.midgetolerantwheat.ca

Adults lay eggs at flowering Larvae feed on developing kernels causing yield and quality loss North Dakota #1 producer of spring and durum wheat in US Hi h risk High i k predicted di t d ffor 2011 based b d on 2010 counts t off llarvall cocoons iin the soil • Average number cocoons in 2009 was 129 • Average number cocoons in 2010 was 417 • Warm, calm and humid conditions favoring greater risk by wheat midge g • Are these favorable conditions temporary or part of the climate change? • • • •

CROWN AND ROOT ROT OF SUGAR BEET

• Crown rot and root rot caused byy Rhizoctonia solani • Critical temperature for infection of the crown is 16°C • Strains of Rhizoctonia solani have changed from AG4 to AG2 AG2-22 in recent years • AG2-2 has higher g temperature tolerance • AG2-2 also goes to Phaseolus beans, soybeans, corn • Has implications p for temperature p increase in Chile

AN EXAMPLE OF CHANGE TO A COOLER TEMPERATURE • Bacterial wilt caused by Ralstonia solanacearum • A worldwide disease of potatoes and tomatoes in tropical climates; • Not in temperate climates like south Chile or the US • A new variant arose about 10 years ago that is adapted to cooler temperatures • Bacterial wilt now present in Netherlands and other areas of Europe • Also infects Geranium and was introduced into the US in cuttings from Kenya • Was eradicated but shows potential for spread of pathogens adapted to a different temperature

POTENTIAL EFFECTS OF WARMING ON POTATO GROWTH

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Irrigation: more needed because warmer and drier, or less because warmer and wetter? Conflicting predictions

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Potato seed performance: Warmer temperatures cause physiological aging of seed and reduced seed performance. Will refrigerated seed storage facilities be needed?

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Potato quality: potatoes love cool nights •

they use the sun to make sugar

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convert sugar to starch at night

• warm nights inhibit this conversion •

reduced potato quality?

WHAT CAN WE DO TO ABOUT CLIMATE VARIABILITY? • Document new sightings and expanded host ranges of diseases and pests • Adjust disease and pest forecasting models for higher temperatures • Allow and utilize lower input, environmentally neutral technologies for crop production • Genetically modified organisms (GMOs) for yield, disease, pest and stress resistance • Find new “green” technologies that are global warming neutral • biologicals/biorationals • Induced resistance • Provide P id more education d ti • By scientists • To consumers

• Developp widelyy adapted p varieties;; farmer friendlyy because theyy are able to thrive in a wide range of (harsh) environments • Develop efficient varieties • That mature early • Need less water • Are adapted to higher temperatures • Are resistant to diseases, pests and physiological disorders such as heat necrosis and heat sprouts • A good example is the most recent variety released from the NDSU potato breeding program: Trailblazer Russet • processing variety widely adapted with good yield • uses 25% less nitrogen • resistant to Verticillium wilt, pink rot and late blight • resistant to sugar accumulation in cold storage

• We do much of this already; we need to emphasize and support agriculture research even more in these times of climate change and variability