Late blight outbreak threatens vegetable growers in the Northeast US.

This summer commercial growers as well as home gardeners will battle the same disease organism that caused the 19th century Irish potato famine. This devastating plant disease thrives in cool temperatures and moist conditions. That’s been the general weather forecast for the Northeastern US this spring and summer, it’s been on average 3°F cooler than the historical average with significantly higher than average rainfall.

For home gardeners, box store/nursery bought seedlings are the apparent source of the disease. Any susceptible plants growing in the vicinity of infected plants can become infected through the natural spread and dispersal of the spores of this fungus-like pathogen. Phytophthora infestans (late blight) can spread by rain washing spores off of plants into the soil as well as wind carrying the spores for miles. This disease is rarely known to overwinter in soil but can reappear readily if growing conditions remain to its' liking. This was part of what caused the Great Irish potato famine. The weather remained cool and wet for consecutive growing seasons, that along with poor understanding of the disease as well as a lack of uninfected seed stock contributed to the crop failures.

This from a New Jersey source:

Seed-grown plants raised at home are not implicated in the outbreak, but are susceptible to infection. The late blight infestation comes in a season when more homeowners than ever have taken up vegetable gardening as a hedge against rising food costs. And cool, rainy weather has created perfect conditions for the disease.

Rain fell in some region of New Jersey every day of last month except June 1, according to state climatologist David Robinson. With statewide rainfall recorded at 6.61 inches vs. the long-term average of 3.79 inches, it was the sixth wettest June on record. Cloud cover kept temperatures down to an average of 67.7 degrees, making it the 24th coolest June on record. - Valerie Sudol of newjerseynewsroom.com

Here's that entire report:

Blight outbreak threatens Jersey tomatoes

Plants affected by late blight are members of the Solanaceae family also informally known as the nightshade or potato family. This family includes the potato, tomato, bell pepper, chili pepper, eggplant, tobacco and petunia. There are a number of common uncultivated toxic plants in this family including Jimson weed, mandrake and deadly nightshade. These too can carry and spread the disease to home gardens and field crops.

This disease can wipe out entire commercial crops. This can be as devastating to Northeast farmers as for example frost is to Florida citrus growers. The following from the same New Jersey report:

Commercial farmers in New Jersey are familiar with the disease and are expected to act quickly to prevent its spread, which otherwise would mean the "certain death" of their entire crop. Officials are more concerned about backyard growers who may not recognize late blight and who may fail to take prompt action to remove infected plants. - Valerie Sudol

As I am posting this thread it is 11:50PM, today's high temp for my town was 79°, it is currently raining, 65°F and the humidity is at 96%. We typically hit close to 90°F daily in July with only sporadic rain. It has rained nearly every day for the past month. I sprayed all susceptible plants (and the soil directly beneath them) in my garden this afternoon with a rather benign organic fungicide. I have yet to see signs of the late blight in my garden but I know how to identify it as it often shows up in the fall after harvest in my area. Although I am a certified master gardener for 28 years, due to the serious consequences of this disease I prefer not to publish my exact gardening methods as nothing is fool proof against this. If you would like information about how to prevent and treat this disease in your garden, I recommend for starters checking out the following links followed by consulting your state's agricultural extension agency. You need to do this now, before you notice signs of the disease.

This first link gives a good overview of the disease and is from Cornell University in New York State:

What is Late Blight?

This following link is both a confirming report of the outbreak as well as treatment instructions and links back to Cornell University's gallery of photos helpful in identifying the disease. From the University of Massachusetts, Amherst:

Late Blight Alert for Potato and Tomato

Keep in mind that identifying this disease in your garden likely means you're too late. Infected plants are goners. Prevention is the only effective treatment for this disease. Good luck fellow gardeners!

I do not know if this is what affected the plants I purchased for my garden this year or not- but not a single plant has matured in a healthy way- despite good soil, watering and protection from pests. Most appear affected.

Since we don't eat meat or dairy products, it is increasingly expensive to purchase store vegetables and fruits- so I've begun cataloging native plants in our area which are edible- and thriving- as I've been growing more concerned about the likelihood of food shortages and bee issues.

I haven't been brave enough to actually EAT any of them yet- but I am getting prepared- in case we have to. This will probably put vegetables and fruit out of our reach, financially.

Good post.

reply to post by Ev0lveUp


I'm sorry to hear of your struggles. I hope you don't give up on gardening. There are health and economic advantages to gardening. Keep in mind that there are many food crops that are not affected by this pathogen and actually thrive in the conditions we are experiencing. Some can be planted now, grown from seed for economy, for late summer and fall harvests. Of course you can also save seed from many garden veggies for planting in the next season.

The obstacles can be daunting when you depend on what you grow to put food on the table. My guess is that if you have the wherewithall to follow threads on ATS you will find a way to continue gardening to some degree. All the best to you and yours!

Thank you for the friendly reply! You know, this is the first time a garden I did turned out absolutely fail...not one plant is thriving. We moved here in the winter, and I naively planted the garden as soon as the season allowed.

We talked to some people in the town yesterday, and it appears the area's well water and soil has been affected by the oil production in the past. Apparently it is not toxic- as it continues to be piped to people's homes ( we drink bottled spring water)- but my plants seem unable to tolerate it- even the ones in the containers.

Have you experimented with the planters which hang upside down? I had several, but I found the water draining out of the planter drained out the nutrients in the soil- and all my plants still wanted to grow up!

Anyway, thanks for the well-wishes.

reply to post by Ev0lveUp


Wow, that is scary. If it's the water supply that has the petroleum or other chemical contamination, then it will be extremely difficult to overcome. I can't imagine an easy way to bring uncontaminated water to your plants. If you had say a tank on a trailer that could be filled off site and then brought back near the garden but let's face it that is a lot of work and expense.

I tend to doubt that your soil at least near the surface of where you're living is contaminated. If that were the case you would notice it as weeds and wild plants would likely show signs of distress. You'd likely have a big barren spot. You haven't mentioned anything like that so it must be solely the water supply. Yikes! Even if the veggies were to struggle through and produce for you I would be afraid to eat anything. It sounds as if you need water and soil testing to determine what kind and level of contamination has occurred. Have you done that? Can you do that? You should.

I imagine the only certain, safe way for you to grow plants would be in containers with either commercial potting soil or garden soil from an uncontaminated area. And, this is important, watered with only rainwater that you've collected or clean water from off site. That's a lot of work. Realistically how much can you grow in containers? I do my veggies that way but I'm not depending on them.

Yes, as a matter of fact I have tomatoes in those upside down hanging planters. It is problematic that the water carries the nutrients out the bottom. And so, you have to supplement with a liquid fertilizer. When I planted my hanging planters I went overboard on organic matter in the planting mix. Bagged peat moss to be precise, once wetted out it holds moisture well. I also added a pelletized slow release fertilizer into the potting mix. But there's not a lot of root room in those small hanging bags and after a few weeks you need to add a little fertilizer to the water.

You can use a number of readily available things. Those blue and green powdered mixes you see in every garden center and in TV adds work just fine. I use them at about half the recommended strength once a week for containers. (If my containered plants look good, no fertilizer!) I've also used liquid fish fertilizer at about half strength. I'm not specifically an organic gardener and so I use what's economical and practical.

Another thing you can do is to add a little more potting soil into the top of the bag. My guess is you'll notice that the soil has shrunk somewhat in the bag. By adding a little more to the top of the bag it will help plug voids that have formed from watering. That should help the water from simply running out the bottom immediately when you water. You don't have to add a lot, a little bit and then check how things are going. You can always add a little more at a later date.

Yep, the tomatoes grow down a little and then they start reaching up for the sun. They don't care where their roots are, they just need sun on their leaves. That's OK, that's what they naturally do, grow up. It also keeps the plants from touching the ground and picking up diseases. It's not a bad concept these hanging planters. It might not be the best way to grow tomatoes but it is fun.

Now, are you watering the hanging tomatoes with the contaminated water? That will kill them too. Keep in mind that your garden soil might have been fine, only you can tell; a soil test from a test lab would let you know for certain. But for sake of discussion let's say your garden's soil was uncontaminated when you started this Spring. If the water you used on the garden was contaminated, now the soil likely has some of the contaminants too. Once that happens it will likely take a huge amount of time and effort to make that garden area safe for growing again.

Hope I didn't bum you out with all this, I just wanted to give you everything that crossed my mind. I know, I don't always think of all the possibilities when I'm dealing with a problem.

Talk to you soon EU! I'll check back with this thread.

Well, I'm in the Rocky Mountains in CO, and caught a case of blight on just one of my tomato plants. I've NEVER had to contend with this here, as the growing season is usually very dry.

This year's been extremely wet though.

I cut off the affected branches, and treated what was left with a fungicide spray. The plant seems to be recovering nicely, but I've isolated it from the rest as best I could, and won't be reusing the soil next year (thankfully it's container grown).

reply to post by Unit541


Excellent, you've taken all the right precautions. It is odd, I'm in New Jersey and we've had an overly wet season too. Keep in mind that your plant might have a different "blight". It might not be the "late blight" and that would jive with you saying your plant seems to be recovering.

This might be of interest:

Tomatoes are the most popular crop in the home vegetable garden. While tomatoes are relatively easy to grow, foliar diseases often occur in the home garden. Early blight and Septoria blight are the two most common foliar diseases of tomato. Early blight produces brown spots (up to 1/2 inch in diameter) on infected leaves. Concentric rings of darker brown often appear in the leaf spots. Septoria blight produces small brown spots (approximately 1/8 inch in diameter) with tan or gray centers and dark edges. Both diseases cause heavily infected leaves to eventually turn brown, die, and fall off. Lower leaves are infected first with the diseases progressing upward during the growing season. Wet spring and early summer weather favors development of early blight and Septoria blight. Defoliation may be severe when favorable weather conditions exist. Early blight and Septoria blight overwinter on plant debris left in the garden. Fungal spores are splashed onto the foliage by raindrops or splashing water. A wet leaf surface is required for the spores to invade the plant tissue.

Home gardeners can help reduce blight problems on their tomatoes with good cultural practices. Fungicides may also be needed.- Richard Jauron, Department of Horticulture, Iowa State University

Here's the entire article. Please read it, it's short and to the point:

Control of Tomato Blights in the Home Garden

From what I've experienced and read U541, the various symptoms from these tomato diseases make accurate diagnosis difficult. There's a lot of similarities and subtleties. However, the precautions you've taken would be appropriate for any of these "blight" type diseases. You mentioned that you will not be reusing that container soil again next year and that was one of the points in the article. If your plant once again shows signs of disease it would be wise to eliminate it completely from your garden. I feel certain you would do that, my mentioning it is for others reading this thread. Also for the casual readers of this thread, I've mentioned using liquid fertilizers and we've also mentioned garden fungicides. Before using any chemical, no matter how seemingly benign, read and follow the label directions. I mentioned my using liquid fertilizers at half their recommended strength. That's me, I've read and understood the directions. I've had training and I'm working from experience. Fungicides and other chemical remedies, even "organic" types can be hazardous. Read and understand what you are working with. Follow the product's labeled safety instructions. Safety first folks!

I would like to point out the most important thing you've done in your gardening Unit541. You are out there in the garden and observing. With busy family lives and work schedules our gardens sometimes get lost for days on end. (Believe me, I know. A couple of days is all it takes to lose an entire season's work.) You've identified a problem and acted quickly, likely saving this years tomatoes. I encourage all gardeners to simply walk through and observe your gardens progress at least once a day. A few minute stroll with your morning coffee or when you get home from work can alert you to problems before they get out of hand. A walk in the garden is a great stress reliever too. Just a reminder!

reply to post by Hemisphere


Thank you for all this information! And no, the indigenous plant life seems to be doing fine, but all my container plants suffered the same as those planted in the ground.

We are using the local water supply but there is a well on the property- the pump was removed by the previous owner due to contamination. I was remiss in naming it 'soil contamination'- but I like the verification you gave on how to check that- so I'm kinda glad I messed that up!

I honestly threw in the towel for this growing season- after all the effort. I did try numerous things, including adding additional fertilizer and making sure the soil was well drained. (While pouring the water on faithfully!)

I'm a little more encouraged after this- this is the hardest I've ever had to work at a garden! ha.

You were awesome to take the time to answer these questions and post the blight info. Thanks