Fruits and Vegetables

Protecting the World's Potato Crops From Late Blight

Something went wrong. Please try again later...
AdobeStock_3839446 - Copy.jpeg

In May of 1846, a London newspaper called The Universe described a desperate situation unfolding in nearby Ireland: “Famine – pale, gaunt, ghastly – is stalking throughout Ireland, withering up men like the flowers of the field, consuming millions of human beings with the breath of his mouth.”1

The year prior, Ireland had been struck by what they would call “The Great Hunger,” or what the rest of the world knows as the Irish Potato Famine. Potatoes were introduced to Ireland less than a century before the famine, but they quickly became a staple food for the population, most of whom lived in extreme poverty. With few prospects for work, many Irish people lived off the land. Potatoes were a practical and nutritious food source for the time, not only for people, but for livestock.2 A lot of potatoes could be grown in a small area and they grew where other crops could not. They were easy to cultivate, requiring only a spade. Most of the population depended on them for their very survival.

In the summer of 1845, the potato crop in Ireland appeared to be healthy. But after that fall’s harvest, the potatoes rotted quickly. They were stricken with Phytophthora infestans, potato late blight. By that November, it was reported that, “One half of the actual potato crop of Ireland is either destroyed or remains in a state unfit for the food of man.” The following season, the crop was completely wiped out. Between 1846 and 1851, more than a million people died from the famine.2 A million and a half more immigrated to North America, forever changing populations and cultures on both sides of the Atlantic. The famine had political consequences, too, sparking calls for Ireland to become independent from the United Kingdom.

The Irish Potato Famine reminds us that crop diseases can have implications well beyond the fields. Today, thankfully, most of us are not dependent on any single source of food. But access to a variety of foods—available in abundance and at affordable prices—still has an impact on health, economics and our daily lives.

The Irish Potato Famine, caused by potato late blight, killed more than a million people in just five years. The disease continues to be a challenge for potato farmers today.

New solutions for an ongoing challenge

Potato late blight is not just a historical footnote, but a disease farmers must continue to battle today. It can decrease yields by 20 to 40 percent. Once it develops, it spreads rapidly through spores distributed by wind and rain.

Potato late blight shows up as brown lesions at the base of the stem, with damage spreading rapidly to the undersides of leaves. The disease attacks the cells of leaves, killing the green areas of plants. By interrupting photosynthesis, it keeps the potatoes below ground from developing to full size. When washed into the soil, potato late blight can also attack tubers themselves, penetrating through small holes in the skin. Infection can continue causing damage after harvest when potatoes are in storage, and it can make potatoes vulnerable to other diseases like soft rot.

In order to fight against potato late blight, farmers need options that offer long-lasting protection, especially during late summer when weather can be unpredictable. Zorvec™ active represents a completely new class of fungicides available against potato late blight. Protection with Zorvec lasts up to 10 days and it’s very effective at low use rates. (A use rate is the amount of a product needed to provide effective control.) When used in rotation with other fungicides, Zorvec helps prevent the development of resistance, so that farmers can continue to battle potato late blight effectively.

Almost two hundred years ago, disease-free potato fields were a matter of survival for millions of people. Today, clean potato fields mean a ready supply of highquality, affordable, nutritious potatoes enjoyed in soups, stews, sides and main dishes everywhere. With innovative fungicide options like Zorvec, farmers can cultivate green fields with confidence in long-lasting control against late blight and bring in abundant harvests they’re proud to deliver to the world.

Learn more about Zorvec active


1 “Is There a Famine in Ireland?,” The Universe, May 19, 1846, pp. 4-5,

2 “The Potato Famine and Irish Immigration to America,” Constitutional Rights Foundation, 2010,