Potato and Tomato North Carolina
Coordinated by 
Jean Beagle Ristaino (Jean_Ristano@ncsu.edu),
Department of Entomology and Plant Pathology, NC State University,


Potatoes are the fourth most important food crop in the world and the leading vegetable crop in the US. Tomatoes, both processing and fresh market, are the second most consumed vegetable in the US, behind potato. Nationwide, nearly 483 million pounds of potatoes and tomatoes are grown annually on nearly 1.5 million acres, with a combined total value of approximately $6.54 billion. Globally, yield losses caused by late blight and the cost of control measures have been estimated to exceed $6.7 billion annually, and the disease is an annual threat to the sustainable production of these two important crops in the US.

Potatoes and Tomatoes
Potatoes and Tomatoes. 
Source: Pixabay


Late blight, is caused by Phytophthora infestans, and is one of the most important management challenges in both tomato and potato production across the entire U.S.

In this iPiPE project, our team will:
1) Enhance and expand the WebGIS capabilities of USAblight.org.
2) Expand pathogen population genetic and genomic tools to monitor and relate pathogen genotypes to important phenotypes including fungicide sensitivity, mating type, host specificity, aggressiveness and pathogen effector dynamics.
3) Expand the BlightPro Decision Support System with a pathogen dispersal tool to enhance the timing of fungicide applications.
4) Track the spread of the pathogen through tomato value chains and engage undergraduate students and citizen scientists to improve management and diagnosis of the disease.
5)Train next generation undergraduate researchers.


Late blight’s polycyclic life cycle, combined with both long-distance inoculum dispersal, in the form of wind-borne sporangia and dispersal in planting materials, makes late blight a “community disease” wherein each producer’s management strategies or lack thereof, can impact an entire region. Because the pathogen spreads easily, prevention is the best control method which leads to extensive fungicide use in order to prevent as well as fight outbreaks.

Monitoring for both the pathogen presence and conducive climatic conditions can improve disease forecasting and reduce the number of fungicide applications. Fungicide resistant strains of the pathogen emerged shortly after the release of metalaxyl in the 1980’s and resistant lineages (US-8, US-11) remain in the US.

Target Pests and/or Beneficial Organisms

Late Blight (Phytophthora infestans)

Late blight symptoms
Late Blight 
(Phytophthora infestans) (Mont.) de Bary
 symptoms. R.W. Samson, Purdue University Bugwood.org

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