Tomatoes will succumb to late blight (Phytophthora) if they’re experiencing cool, soggy summer weather. However, there are several hybrid tomatoes bred to resist blight and other diseases.
I live in the upper Midwest and last year my ‘Black Krim,’ ‘Brandywine,’ and ‘Green Zebra’ tomatoes were infected. Late blight had never been a problem previously, but we also had a chilly, rainy growing season.
Below photos show late blight lesions on tomato fruit and leaflet. Credit: Cornell University
Read Next
When I lived and gardened in Texas, early blight (Alternaria solani) was a huge issue. I practiced pristine garden hygiene and mulched plants thickly to prevent the fungal spores of early blight from splashing up from the soil on to plant foliage when it rained or I watered. Late blight fungal spores, however, are airborne and invade everything that is susceptible, such as tomatoes, petunias, and potatoes. There is little defense other than chemical sprays once the fungal disease is spotted. That’s why commercial growers and home gardeners alike lost most of their tomatoes.
New Tomatoes to the Rescue
Plant breeders are offering us different methods to avoid blight damage in tomatoes: 1) grafted plants and 2) a hybrid bred to resist Phytophthora and Alternaria.
Any tomato variety can be grafted onto rootstock that is resistant to blight and other diseases. Asian, European, and Israeli .jpg)
horticulturists have been doing so for years. (Almost 95 percent of Japanese vegetables are produced from grafted plants.) Territorial Seed Company is exclusively offering several heirloom, paste, cherry, and beefsteak tomatoes grafted to ‘Emperador’ rootstock, which is highly disease-resistant. More companies will be bringing grafted plants to market soon.
There are a number of hybrid tomatoes bred to resist blight and other diseases. Johnny’s Selected Seeds teamed up with North Carolina State University to breed Defiant PHR, a midsize determinate tomato that is highly resistant to all strains of early and late blights. Other blight-resistant open-pollinated tomatoes are ‘Santa’ and ‘Juliet’ and 16-ounce tomato ‘Legend’. ‘Hefty Legend’ was bred by tomato guru Dr. James Baggett at Oregon State University.
Given this year’s extraordinary winter weather pattern and the climate extremes we’ve experienced in the recent past, I’ll be planting some of these blight-resistant tomatoes along with my usual heirlooms to make sure that I have a tomatoes for those first long-anticipated BLTs and salads.
If you have comments, questions about tomatoes, or tips for a better tomato garden, please share! Just post your comment below.
Doreen G. Howard
ADVERTISEMENT
My first tomato plants were determinate romas, and they produced quite a crop. I was encouraged and as my yard gets sufficient sunlight, I moved on to some determinate varieties. I got some fruit, vanquished blossom end rot with a bit of love and calcium. Then the plants began wilting bottom up. Got a few more fruit but once it was apparent I might have fusarium or verticillium in the plants, I destroyed them.
This year I tried again. Grew some lovely tomato varietals from seed including Brandywine and Cherokee chocolate and they flourished until the weather settled into the 70s for the past two weeks. Since then, although they are potted in new soil, they are all rapidly dying of wilt. Is there anything I can do to clean up the environment in the backyard? If one of these wilts is in the peripheral soil in the garden, will it come back forever?
Should I try wilt resistant plants for a few years? Does fusarium/verticillium ever cycle out of an environment?
Second issue, I bagged the dirt from last season’s diseased crops because it’s difficult to dispose of, and wanted to try solarizing it. Instead I steamed it while also alternately bathing the soil in a diluted hydrogen peroxide bath. I steamed it in layers about an inch thick so it was fully permeated and theoretically there should be no disease left in the soil, if what I’ve read about steaming is correct. Can anyone confirm this? I reused it for a few other types of plants after cleaning and it seems to be causing no issue.
Did anyone ever answer her? I'd like to know as well! TIA
please email to me their phone # and address
See our list of seed catalogs; Territorial is listed. /content/garden-seed-catalogs-mail
I've planted tomatoes for the last 3 years in the same big containers 3 plants to a each tub 6 total all close together on patio, do I need to change dirt in containers ? I'm afraid of the blight , they've done done great for all the.last 3 years !
During the course of one growing season the plants will use up the nutrients in the soil, so it is alwasys best to replace the soil. It’s also good practice to wash the containers with a bleach solution (1 part bleach to 10 parts water).
If we plant too late, we get white spots in the tomatoes, We have moved them around in the garden and that does not help. Only getting an early harvest helps to prevent this. Is there any other way to stop this problem?
how often do you water
Septoria leaf spot or blight will cause white spots on leaves and can occur during humid conditions when plants are so close as to have poor air circulation around them.
White spots on the fruit could be a bacterial canker, one of the most difficult problems to control. This, as you suggest, could come from the soil—specifically from not rotating. The thing is, avoidance is depent on rotating out the entire nightshade family. That includes tomatoes, but also eggplant and potatoes as well as peppers and tomatillos. You should avoid planting tomatoes, eggplant, or potatoes in the same soil, or each other's soil, for two to three years (some say, unequivocally, three years).
When you find a new spot for the tomatoes (and other crops, if you grow them), use rich compost and check the pH.
If you do all of this, kudos, but you still get the cankers, it could be that the problem originated in the greenhouse that produced the seedlings (you did not cite the origin of your plants). Elmination of an "industrial" problem involves sterilization of virtually everything, from tools to soil.
Perhaps it's not too late to get "new" soil for new plants and grow them in pots.
Hi. I'd like to try planting fava beans again. I've tried before but the fruit and leaves turn an awful black, shrivel and die. What is causing this? I'm kinda new at this
