Late Blight? What to do now!


Infected Potato Plant Leaves

One of the worst problems that could happen in your garden isn’t pests- its a late blight. Late blight is a destructive fungal disease, and did we mention it is highly contagious? Tomato and Potato plants are the most susceptible to this disease. Action is needed to be taken immediately to prevent the destruction of your harvest. The epidemic of this diseases that occurred between 2009 and 2011 was started with just a few infected plants. There are many steps that can be taken to prevent Late Blight, here is a list to help you.

  • Select plant varieties that have resistance to late blight. One type of tomato that is resistant is the Jasper Tomato.
  • When planting potatoes, Do not plant from last years garden or even from the grocery store. There is a higher chance for the late blight pathogen (Phytophthora infestins) to be in “table-stock” potatoes.
  • Get rid of any potatoes that have grown as “volunteers” in compost piles or from un-harvested potatoes from last year.
  • You always want to inspect your tomato seedlings carefully for blight symptoms before purchase. Seedlings will only become infected by growing near other infected plants. The seeds do not carry the disease within.
  • Learn the different symptoms of Late Blight and its imitators. Also monitor the occurrence of Late Blight in the United States by visiting
  • Inspect your tomato and potato plants at least once weekly. Happy planting!

What to do when late blight symptoms are found: Immediately call our Horticulture Diagnostic Lab at our hot line at 631-727-4126 from 9 a.m. to noon, Monday through Friday. Alice Raimondo and Sandra Vultaggio, our Horticulture Consultants, can help determine whether you do, indeed, have late blight, and answer questions about proper handling of an outbreak.

Thank you Cornell University for the original information. You can read more here. 

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