Welcome to USAblight

late blight lesion on potato

Potato late blight lesion.  Image courtesy of Jean Ristaino, NC State University.

Welcome to USA blight, a national website that acts as an information portal on late blight.  You can report disease occurrences, submit a sample online, observe disease occurrence maps, and sign up for text disease alerts.  There are also useful links to a decision support system, and  information about identification and management of the disease.

Late blight of potato and tomato caused by Phytophthora infestans is a devastating disease worldwide and led to the Irish potato famine in 1845. Under favorable weather conditions, tomato and potato crops can be destroyed within days. Yield losses caused by late blight and the cost of control measures have been estimated to exceed 6.7 billion dollars annually and the disease is a major threat to food security worldwide.   

Phytophthora workshop held in India

A workshop on "Rapid Diagnostic Tools for Identification of Phytophthora species on Horticultural Crops " organized by Dr. Jean Ristaino, with the assistance of Dr. Pallem Chowdappa and Dr. David Cooke was held at the ICAR- Central Plantation Crops Research Institute, Bangalore India, Sept 8, 2015 preceding the 3rd International Phytophthora Symposium, Sept 9-12.  Over 120 participants applied for the workshop that included 30 students from diverse research institutes in India. The hands on laboratory training in morphological and molecular identification of Phytophthora species included use of a diagnostic Lucid key, PCR and molecular sequence based identification and rapid assays for identification of Phytophthora infestans.  


A workbook was distributed to workshop participants and is available here

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Late blight and other Phytophthora diseases emerging in India

Late blight and other Phytophthora diseases emerging in India

Over a hundred and twenty different Phytophthora species affect tropical and horticultural crops globally and are an emerging problem in India. A 4-day symposium organized by Dr. Pallem Chowdappa of the ICAR-Central Plantation Crops Research Institute on “Phytophthora: Taxonomy, Genomics, Pathogenicity, Resistance and Disease Management was held in Bengaluru India Sept 9-12.  The meeting included plenary presentations by invited international guests on emerging Phytophthora diseases, taxonomy and phylogeny, population biology, genomics, pathogenesis, epidemiology, host resistance and disease management. 

A team of international Phytophthora researchers gave plenary talks on:

  • Current and emerging Phytophthora diseases – research challenges and impact - Dr. André Drenth
  • Evolutionary origins of US and famine-era lineages of Phytophthora infestan - Dr.  Jean Ristaino
  • New tools to understand evolving populations of Phytophthora infestans on regional, national and international scales for improved late blight management - Dr. David Cooke-
  • Genome evolution in filamentous plant pathogens- Dr. Sophien Kamoun
  • From genomics to effectors: how understanding oomycete biology has contributed to disease control - Dr. Brett Tyler
  • Management of Phytophthora diseases in the tropics - Dr. David I. Guest
  • Management of Phytophthora blight (Phytophthora capsici) of peppers - Dr. M. Babadoost
  • The 30 year journey: Integrated Phytophthora root rot management in avocados- Dr. Elizabeth Dann
  • In search for new targets to control Phytophthora pathogens - Dr. Francine Govers

The well-attended meeting also included inaugural and cultural events, a field tour, a trade show and a valedictory honors ceremony.  A symposium report and recommendations for future Phytophthora research in India were given by the international team. The team of late blight researchers met with Indian late blight researchers and discussed the need for global monitoring of Phytophthora infestans populations. Dr. Pallem Chowdappa reported the emergence of the 13_A2 lineages of the pathogen in India and its shift to tomato.  Dr. Sanjoy Guha Roy from West Benagal State University discussed his work on characterizing late blight outbreaks in the northwest of the country in 2014.  Dr. Sanjeev Sharma from the Central Crops Research Institute in Shimia presented data on a decision support system for late blight, development of transgenic varieties and characterization of populations in India.  The need for coordination among the Indian and global research teams including Euroblight and USAblight and a global monitoring network for late blight were discussed.

3rd International Symposium - Phytophthora: Taxonomy,Genomics, Pathogenicity, Resistance & Disease Management


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