By Peter Heffelfinger
posted August 30, 2022
Tomato Blight: Early and Late
Tomatoes are susceptible to two different kinds of fungal blight, an early mid-season variety, and then a different late-season type. In past years I’ve only had to deal with moderate attacks of late blight, which emerged towards the end of the growing season, initially blackening the main stems and then moving onto the outer branches and leaves. Usually it only had a minor effect on the main crop of tomatoes, which had already ripened on the vine. Many of the still-green tomatoes would have enough of a slight orange or yellow tinge to eventually ripen if laid out on newspaper in a warm room. Even fully green, hard tomatoes would also eventually color up to a degree, sometimes lasting until Thanksgiving, and could be cut in half and fried until fully soft.
This year is the first time I’ve had to deal with early blight, which first blackens and kills the leaves and then gradually moves onto the main stems in blotches of white. The only strategy at this late stage is to keep cutting off the affected leaf stems and removing them from the garden to inhibit the spread of the spores. The fruit is still edible, but the ripening process seems to be slowed down, given the loss of leaves, and the total yield of the crop has been reduced. Many of the already red tomatoes remain firm on the vine but don’t seem to get to the fully soft, ripe stage, even when picked and laid out on a table for several days. A few of the large Italian heirlooms got truly ripe prior to the early blight; now, I’m still waiting for the Mennonite Stripe and Heirloom Beefsteak varieties to fully ripen, as well as the standard Big Boy. The determinate Romas, being smaller bushes that have reached their full height, lost most of their leaves to the blight and are toppling over from the weight of the semi-ripe fruit.
All the indeterminate vines are still producing suckers and new foliage at the top, but the main leaf area has become a mass of blackened and dead leaves. The early blight emerged about a month ago, about the same time that the local maples trees in shaded areas developed a white coating on their leaves, as if covered with a thin film of frost. A local retired nurseryman said it was linked to the cool night time temps combined with the heat waves. The only chemical treatment would be to spray with copper, but at this point it’s too late for that to work. Maybe next year an early, preventive treatment with copper, and then repeated applications during the season would help stave off both the early and the late blight. Since the dried, blackened leaves shatter easily as they’re removed, the spores are already getting into the soil and will emerge again next year.
For now, I’m preserving as many of the tomatoes as I can, processing them skins and all and freezing in quarts. To sweeten the mix up a bit I add a number of fully ripe Sungold and Yellow Pear cherry tomatoes, which fully ripened much earlier and were initially less affected by the early blight. I’m also drying two types of larger, more oval cherry tomatoes: the Italian heirloom Principe de Borghese, originally bred for sun-drying, and the modern variety Juliet, which given its classical name is perhaps a related Italian descendent. As an experiment I’m also drying the small Yellow Pear cherry tomatoes, which aren’t as sweet tasting as the Sungolds but have more solid flesh. Trying to cover all the tomato bases.
Fortunately the pepper plants adjacent to the tomatoes are not affected by the blight and are producing bumper crops that are healthy so far. I harvested a large number of mildly hot Green Padron peppers, which I roasted in safflower oil for freezing in pouches. I’m waiting for a crop of hotter Red Padron as well as Green/Red Shishito roasting peppers. Other hot peppers include: Hungarian Black/Red: Korean Dangjo Cheongsam Yang Purple/Red peppers, similar to Serranos; a Korean drying pepper, moderately hot; Sarit Gat, a Yellow Cayenne; Bangkok Hot, a long thin, fiery hot Thai chili for sauce or drying; a slightly milder type of Habanero; Black Pearl, a decorative pepper with upright facing fruit that also ripen into very hot red edibles; and a regular Anaheim. I have already used the first ripe orange Habaneros to make Piri-Piri/Pili-Pili, a Brazilian/African fresh vinaigrette sauce made with garlic, onion and lemon juice. Definitely hot.
Sweet peppers include the standard North Star Green/Red peppers, and three Italian varieties for roasting: Giant Marconi and Sweet Bull’s Horn, both very long green/red varieties; and Cornito Giallo, a yellow to orange tapered pepper.
My one green tomatillo plant, unaffected by the blight since it’s not related to tomatoes, is producing a steady crop. Along with the green tomatoes and green Padron peppers tomatillos are useful for making salsa verdes and a classic Mexican chicken chipotle stew. Since my cilantro plants went to seed in the heat, I have also been using the green seeds (now considered coriander) as an alternative to leaf cilantro, as well as the spice for home cured salmon gravlax, instead of the traditional dill leaf. Use what you have on hand.
The standard salad cukes are now hanging on the trellis in the hoop house. I use them mostly to make the Greek appetizer tsaziki: peeled and grated cucumber, squeezed gently to remove excess moisture, then mixed with Greek yogurt, garlic, red wine vinegar, salt and cumin. I find it’is a way of dealing with a surfeit of cucumbers before they soften off the vine. A refreshingly cool dip useful during the heat dome days.
More Fall, Winter Plantings
Late August usually provides a small window of cooler weather and perhaps a bit of light rain, an opportunity to get in additional semi-hardy fall/winter crops. This week I sowed a tapered root White Icicle radish, a Watermelon Radish that produces white globes with a bright red interior, as well as Mizuna Mustard and Purple Top Turnip. I keep the soil of the freshly seeded rows moist at first by laying down cardboard to protect against the heat of the sun. Once the sprouts surface I replace the cardboard with the black plastic open lattice nursery trays to provide a bit of temporary shade for the young plants as well as protection against the local cats that love to use the freshly turned dirt as outdoor litter boxes.
I also have transplants of an Italian leaf broccoli, Spigariello Liscia, similar to broccoli Raab, which along with the other young fall/winter brassicas is under white row cover to protect against the cabbage butterflies that are now appearing. The semi-hardy Liscia leaf broccoli, if left under the row cover in the winter will provide fresh florets, stems, and leaves through the hard freezes. Think ahead to winter in late summer.
Oh no! I’m so sorry you got hit by early blight. That’s awful. Did any of the plants show resistance? I’d be curious about saving seed from less-affected individuals to try and breed for early blight immunity… but gosh, that’s a big project and you already have a lot going on!
Unfortunately none of the standard tomato varieties showed any resistance to early blight. Some of the heirloom varieties got it first, while a few of the modern types are only showing it now. The hoop house was moved this year from the old site that had grown tomatoes for 6-7 years or more, with only a small amount of late vlight showing up. Maybe should have stayed where it was? However, given the milky bloom on the maple tree leaves in early summer, I think the conditions were right for a general increase in fungal growth.
I did notice that that the Yellow Pear, Juliet and Sweet Million cherry tomatoes have much less blackened leaves at this point, but one of the two Sungolds is pretty bare now, while the second is about half gone. The indeterminates are still sprouting fresh leaves on top, while the determinates of course have stopped growing altogether.
I did talk to Laurie Sherman at the Farmers Market today, who said the Middle School greenhouse has it too, in spite of concrete floors. At least the tomatoes aren’t affected, but seem to be ripening slower. Evelyn says her plants have been spared so far, so you might check her plot.