Strain-specific late blight forecasting

View the project final report

• 2013 annual report
• 2014 annual report

Commodities

• Agronomic: potatoes
• Vegetables: tomatoes

Practices

• Education and Training: decision support system, extension, on-farm/ranch research
• Farm Business Management: risk management
• Pest Management: field monitoring/scouting, integrated pest management, weather monitoring

Late blight caused by the pathogen Phytophthora infestans, has been a major threat to global food security ever since the Irish famine of the 1800's. In the US, late blight is potentially important on nearly all of the approximately 1.2 million acres of potato production. Over 2000 tons of fungicide (active ingredient) are used annually on potato, typically spread over 8-18 applications. The total global cost of the disease is ~$7 billion per year. On tomatoes, the disease can be and has been equally devastating. The most recent example occurred in 2009 when infected tomato transplants were distributed via national large retail stores who obtained transplants from a national supplier. The subsequent pandemic in the mid-Atlantic and Northeast regions eliminated tomato plants in many organic farms and home gardens. My work will have tangible economic and environmental benefits by leading to lower on-farm expenses, reduced fungicide applications, and more sustainable production. I have recently characterized phenotypes of the four most important strains of this pathogen, and this information has been used by growers throughout the Northeast to make informed management decisions. I now propose to characterize a novel set of strains (detected in the Northeast), because any one of these might become a dominant strain in the future. The data I will provide will enable rapid appropriate response to that particular strain. This information will be used in a disease forecast hosted on the Cornell Decision Support System. This DSS is available to anyone in the Northeast at http://blight.eas.cornell.edu/blight_lab/.

My overall objective is to provide the data necessary to construct a strain-specific forecast for late blight of potato and tomato. This will be achieved through four specific sub objectives:

1. Determine host preference for new genotypes of Phytophthora infestans strains collected in the Northeastern US in the years 2010 and 2011.

2. Determine the effect of temperature on incubation period (time between inoculation and the appearance of typical late blight symptoms), latent period (time between inoculation and the start of the production of spores), sporulation capacity and lesion area.

3. Determine sensitivity to an important fungicide (mefenoxam) of P. infestans strains collected in the Northeastern US in the years 2010 and 2011.

4. Determine the effect of temperature on the rate of germination for new genotypes of P. infestans strains collected in the Northeastern US in the years 2010 and 2011.