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Late blight reports are on the rise!

Posted: September 8, 2011

Due to the cool and wet conditions over the past wekk or so there have been an increasing number of reports of late blight in Pennsylvania and New York.
Current map of confirmed reports of late blight on tomato and/or potato as of 8 Sept 2011 as reported on the USAblight website. Reports within the past week are in red while reports in blue are over a week old.

Current map of confirmed reports of late blight on tomato and/or potato as of 8 Sept 2011 as reported on the USAblight website. Reports within the past week are in red while reports in blue are over a week old.

On Sept 1, 2011 late blight was confirmed on tomato in a home garden in Mercer Co., PA. The homeowner has since destroyed the plants. Earlier this week late was confirmed on potato in a commercial field in Erie Co., PA. The weather in the Northwest corner of PA has been perfect for late blight this past week with the heavy fog and early morning dews in addition to some sporadic thunderstorms. Samples from both confirmed reports have been sent for genotyping. So far this season, there have been four confirmed reports of late blight in Pennsylvania.

Additionally reports are coming out of New York on both tomato and potato almost daily so although we are nearing the end of the season, vigilant scouting is still important! For potato growers, foliar infections late in the season can still lead to tuber infection so consider vine killing immediately or applying a fungicide like Gavel, Previcur Flex or Ranman. The spores can wash off the leaves into the soil and directly infect the tubers especially when the soil is saturated and vines are not adequately hilled.  

Remember that late blight is a community disease! If you suspect late blight please contact your local Penn State Cooperative Extension Office, the Penn State Plant Disease Clinic or Beth Gugino at bkgugino@psu.edu or 814-865-7328. For the most current map of confirmed late blight outbreaks please visit http://usablight.org.