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Help identifying tomato disease

18 years ago

I should be putting up peaches but I'm too busy obsessing about my tomato plants. I had this last year for the first time. That was the year we had so much rain, and of course this year we've had a lot of rain from spring on through June, although it's down to raining only about once a week now and probably will dry up altogether if it's anything like last year. The plants start out great, bloom and set on lots of fruit. The fruit is normal. Then, about mid-July, the foliage begins to yellow at the bottom. Then the side-branches start to turn yellow and die. I can go out and break off the side-shoots and remove all the yellow leaves, and the vines try to send out a new branch, but the main branch it comes off of eventually turns brown and dries up so it is short-lived. The plant does not set on much fruit, and what it set on last year after this started happening was small and deformed. I've looked at pictures and I just don't see anything that looks like this. What do I have and how do I get rid of it? I just came in from cutting two plants all the way to the ground. I thought I'd plant my little plants I started for fall tomatoes in their place but I'm afraid of spreading whatever this is.

Comments (7)

  • 18 years ago
    last modified: 11 years ago

    Ilene,

    Diagnosis is difficult because what is happening on plants in the field NEVER seems to exactly match what I see in photos on the internet OR in photos in my Seminis Tomato Disease Book, and it sounds like you're experiencing the same thing. Sometimes this happens, though, because 2 or more "problems" appear simultaneously and that makes a firm diagnosis more difficult. And, some of the bacterial and fungal diseases resemble one another in the earlier stages.

    Before we get too deeply into an attempt to diagnose what is wrong, can I ask a couple of questions?

    First, when the yellowing FIRST appeared, were your temperatures high....say in the 70s at night and 90s in the daytime, or might they have been more like the 60s and 80s? It matters, because some diseases show up in somewhat cooler weather and some show up in somewhat warmer weather.

    Secondly, did you see any sort of brown, gray or grayish-brown spots or specks on the leaves either right before the yellowing started, or shortly thereafter? And, if you did, were the spots all one color? Or, were there concentric target-like circles with rings of lighter and darker tans or browns in the same circle? And did you see necrosis (dead tissue, possibly showing up as a 'hole') in the center of the brown circle?

    Third, when the yellow begins on the lower portion of the plant, does it ever show up first on only one side of the plant and progress up that one side for a while before spreading to the entire plant?

    Fourth, does new green growth, possibly with blooms and even perhaps accompanied by fruitset, continue at the top of the plant even as the disease travels upward from the bottom?

    Fifth, do you see any spotting on the fruit that was already set and enlarging as the disease progresses? Any brown circular speckling or spotting or scabby raised lesions on the green fruit that seems related to the disease? Or, on red fruit, do you see any sunken spots that show some discoloration?

    If you had described the problem to me with no photos, I would have assumed Early Blight because that tends to show up here roughly around the 3rd week of June and I am used to seeing it. (It is mild here this year thanks to our moderate drought.)

    But, when I looked at the photos, I had a totally different reaction. Here's the play-by-play of what I thought as I went through the photos that first time:

    Photo #1: Spider Mite damage? Well, she didn't mention any spider mites, but the speckled leaves are what I get with spider mites.

    Photo #2: Fusarian Wilt? The leaves aren't as bright yellow and splotched with brown concentric rings as what I see with Early Blight, so it may be Fusarian.

    Photo #3: Spider Mite webbing? And, what are the little white particles? I don't usually see those here, so I am baffled. I see browning on the leaves, so probably not Early Blight or I'd see more yellow. Maybe Septoria?

    Photo #4: Fusarian Wilt? Southern Blight? No, wait, SB doesn't start with yellowing, just very fast overnight wilting of seemingly healthy green plants. So, back to Fusarian.

    Photo #5: I don't see evidence on the green tomato of any bacterial speck or spot or canker or anthracnose, and still think the tannish spots on the leaves look like mite damage.

    Photo #6: Hmmm. Still don't see as much blotchiness as I'd expect with Early Blight, Bacterial Speck or Bacterial Spot, and think it is too hot for the last two to just now be starting up. It is too hot for Late Blight which, despite its name, needs significantly cooler temps. than we have in July. I don't think it is Gray Leaf Spot because that should be on leaves only, and not stems. I don't see enough spotting to make me think Septoria Leaf spot. So, I return to the mottled leaves and still think red spider mites. MAYBE Fusarian Wilt as the primary problem and spider mites as a secondary problem is what I'm thinking at this point.

    Ever had spider mites? See any red dot-sized critters on the undersides of leaves and webbing/mottling on those leaves? (sigh) I haven't had spider mite damage in quite a few years now, but I remember Dad having it yearly and in some photos the speckled appearance of the leaves and what looks like webbing on the back of that one leaf is what he always saw with spider mites. (I should have paid more attention, but I was still a kid when he had his worst spider mite years.) Even if I am seeing some spider mite damage, something else is obviously going on with the foliage, and I lean towards likely being something fungal more than something bacterial. The answers to the five sets of questions I asked above should help us narrow down the foliar issue some more.

    And, if you had run six more pictures, you might see my train of thought run in six more different directions.

    The difficulty of proper diagnosis is why so many of the "what's wrong with my tomato plant/foliage" questions on the tomato forum and tomato pest/disease forum don't get a lot of attention---it is really hard to diagnose via photos. And, it is important to get a correct diagnosis in order to figure out what to do next.

    Dawn

  • 18 years ago
    last modified: 11 years ago

    Hard questions, Dawn!

    1. I'm not sure about the temps, but it's been going on for several weeks now so it might've been about the time we started having warmer weather. My guess would be temps of 70's at night, 90's in the daytime. But it's a guess, as I really didn't take note of the temps when I first noticed. It seemed like we were still getting a lot of rain and I remember thinking that all the moisture was causing the yellowing of the leaves at the bottom.

    2. When the leaves first turn yellow, the veins remain green. There are no spots. As things progress, the leaf develops brown areas and eventually the whole leaf turns brown. Maybe you're right about having more than one thing going on, because I found a leaf on another plant that was green with yellow areas and brown splotches. There are some white speckles near the stem of the leaf. The brown splotches are not concentric, it looks like necrosis and there are a few holes. When the leaf turns brown, the edges curl up along the sides and then under at the point. The veins are the last part of the leaf to turn brown. The yellow spreads up the stem to where it joins the main stem. I can break them off at this point and there is another leaf that tries to grow out at that junction, but it gets sick and dies, too, and eventually the main stem turns brown and dry.

    3. Not sure. It does seem to affect some branches worse than others at first, though.

    4. Yes. But the fruit does not mature. It is usually deformed and remains small.

    5. I have picked some green tomatoes that have a kind of a "rash" area -- raised tiny dark spots that kind of remind me of early stages of mildew. They're not all that way, though, and otherwise the fruit has not been affected.

    I don't see any spider webs.

    Does any of this help?

  • 18 years ago
    last modified: 11 years ago

    Ilene,

    It does help.

    Here's why the temperatures are important. I sometimes see either bacterial speck or bacterial spot in my garden during very cool and rainy periods, which means that here in Love County I see those diseases most often in March through May. So, it is not inconceivable that you had them appear in June since y'all were cooler and wetter than we were at that time. If you have bacterial diseases present in your soil, you can never really get rid of them. They spread via the splashing of rain, water runoff during heavy rainfall or irrigation, insects, tools, and people working around the plants (can transfer bacteria from plant to plant via your hands, gardening gloves or tools). The bacteria survive in and around your garden on debris from past plants, volunteers from seed from diseased plants, and even in weeds.

    Bacterial Speck (Pseudomonas syringae) is the one I see earliest in the spring, often in March and April. It appears when plants are wet and temperatures are in the 55 to 77 degree range, often right after the plants are transplanted into the ground. It shows up first as small dark brownish-black specks on the leaves, and sometimes there is a very, very narrow ring of yellow around the brown specks. This disease affects leaves and foliage, but only affects green fruits (and, normally, it appears before you'd see any ripe fruit in our climate). On the fruit, the infection shows up as really, really small dark specks, less than 1/16" in diameter. Sometimes the part right around the specks is darker green than the rest of the tomato. The specks may be slightly raised above the surface on green tomatoes, but as the tomatoes ripen and the disease progresses, the infected areas become sunken and generally you will not see ripening around those specks.

    Bacterial Spot (Xanthomonas campestris) is the one I usually see second earliest in the year, if I see it at all and I'm more likely to see it from late April through late May. You will see it when weather is warm and either humid or wet or both. It appears when temperatures are in the 75 to 86 degree range. The bacteria enters your plants through natural openings or wounds and can infect the stems, leaves and fruit. On the leaves, the spots are dark brown, take on a sort of "greasy" appearance when foliage is wet, and are very small, rarely exceeding 1/8" in diameter. It is hard to tell what you have when Bacterial Spot first appears because in its early stages it is virtually identical to Bacterial Speck and to the early stages of Septoria Leaf Spot, which is fungal and not bacteria. However, if the leaf spotting does not progress to lighter gray centers in the middle of the older brown spots, you know it is not Septoria. With Bacterial Spot, first you have the brown spots, then you see a general yellowing of your leaves and then the leaves take on a scorched (brown and dead) appearance. Foliar blighting (rapid death) progresses upward on heavily infected plants. If you have fruit on the plants at this point, you'll see the fruit spots appear on the green fruit as raised, scabby spots that are very dark brown and can be up to about 1/3" in diameter, although many stay smaller than that. If you have ripe fruit, the spots turn into sunken areas that look water-soaked.

    Once you have bacterial speck and spot, there is no cure so all you can do is practice good crop roation and good sanitation. The bacteria survives on plant residue or debris, including seeds (so don't save seeds from infected fruit and don't let volunteers live if they sprout in that area). Mulching helps because it keeps bacterial residing in the soil from splashing up onto plants when it rains. Watering only with soaker hoses or drip irrigation helps, but you can't control dew or rainfall.

    Watch your peppers closely, because if you have bacterial spot (and I think you may), it can spread to them. Bacterial speck and spot is a problem whenever leaves stay wet, so you've certainly had the conditions for it these last two years. You can spray weekly, but it needs to be with a bacteriacide and not just a fungicide, so look for something that is a mixture of a fungicide PLUS copper. It won't entirely prevent the disease, but it helps reduce its incidence, slow down its development and helps you get a better yield from infected plants.

    Bacterial Canker is less common, at least in my garden. It is caused by Corynebacterium michiganensis and it is really hard to diagnose because its symptoms look so similar to those of several other diseases. A lot of people think you can identify it by the stem canker that show up with it, and you can, but it does not always show stem canker in every case. Canker shows up mainly as scorched (brown, dead) leaves and blight (death) from the lower part of the plant at first and then moving upward. One way to know if you have Bacterial Canker is to split open stems on affected plants. If the stems have internal discoloration that is a streaky mix of reddish-brown and yellow, you have baterial canker. Eventually, as the disease progresses, you'll see whitish cankers on the stems and leaf petioles, although sometimes the plant dies before symptoms progress that far. You'll get canker spots on the fruit, about 1/8" to 1/4" in diameter and they have a brown center surrounded by a white ring. They're often referred to as birdseye spots. If plants are infected with canker early, they usually die. Sometimes if they are larger and stronger, they may survive.

    If you had sudden wilt and death, but did not see yellowing on the leaves, I'd suspect bacterial wilt. It is easy to diagnose "after the fact". Just suspend in a glass of water a clean, cut end of a stem from an infected plant. If what killed your plants was bacterial wilt, you'll quickly see a sort of milky-white stream of slimey bacterial cells flowing into the water from the stem. If you have bacterial wilt, it is VERY hard to eradicate. Remove and dispose of all affected plant debris and don't compost it.

    I guess that I most strongly suspect Bacterial Spot, but also think maybe Fusarium Wilt, which is viral and not bacterial. So, here's a little about Fusarium Wilt.

    Fusarium Wilt is caused when the pathogen Fusarium oxysporum sp. lycopersici invades a plant's vascular system. It probably is the most commonly seen wilt disease in our state. (A lot of people think they have Verticillium Wilt, but it isn't found here, as far as I know.) This is how it progresses. See if it sounds like what you saw on your plants.

    First you see a yellowing of lower foliage and those yellow leaves do eventually wilt, brown and die. Sometimes, but not always, it appears first on one side of the plant and then progresses upward for a while before it moves to the other side of the plant. If you have this and you are not sure if it is Fusarium Wilt or not, cut a stem or petiole from an infected plant and inspect it. You'll see some reddish-brown discoloration in the tissue between the pith (stem center) and the outer green part of the stem. When I go to the OSU Fact Sheet that contains info on Fusarium Wilt, the color photo on it looks a lot like some of your photos.

    Fusarium Wilt is a late spring to early summer disease here, usually appearing when daytime temps are in the 80 to 90 degree range. There are at least 3 known races of Fusarium Wilt in tomatoes, but I think race 3 is only in California. Modern-day hybrids often have some resistance to one, two or all three races bred into them. You'll know by the appearance of F, FF, or FFF in the letters that follow the hybrid plant name. Heirlooms may or may not have resistance--it's just that no one has tested them to prove if they do or not. Unfortunately, resistance is only resistance and not immunity.

    If you have Fusarium Wilt, it will live in your soil forever. It also is seed-borne, so you can get it through no fault of your own. I don't know what kind of soil you have, but it seems to be worse in sandier soils (I don't know why). I might lose 1 or 2 plants a year to it some years in my clay soil, and none in other years.

    Early blight is my worst disease here, and I am not convinced you have it since you didn't see obvious concentric, target-like brown circles surrounded by yellowing leaf tissue. It is caused by Alternaria solani and is the most common leaf-spotting fungal disease in Oklahoma, and perhaps all over the country as well. Early Blight causes excessive defoliation and, because it often appears when fruit load is very heavy, that can lead to sunscald and fruit loss. When I have EB showing up on a plant, I promptly pick all the fruit the minute they hit the breaker or "blush of pink" stage. EB will move from the leaves, where it first shows symptoms, to the stems and even the fruit. (I get my fruit off the plant before it can move to them though.) EB starts at the bottom and progresses upward with lower foliage sloughing and dying off. SOMETIMES, with SOME plants, new growth comes out and the plant actually "outgrows" the disease and survives. In my garden, Brandy Boy and Snow White are two plants that often survive EB, but a lot of others do not. I usually SEE signs of EB the third week in June, when we are really hot and humid, but have seen it as early as the second week of May, if May is a hot month. EB most often attacks stressed plants, but ALL plants in Oklahoma are stressed, aren't they? Sometimes the stress is too much heat or too much or too little rain, but even just carrying a very heavy load of ripening fruit is enough to stress the plant so it is susceptible to EB.

    I don't think you have Septoria Leaf Spot because you have tons of really obvious small spots with it, and in your photos, I see larger brownish areas.

    I have practically written a book and don't know if I've helped at all. I don't have much experience with Gray Leaf Spot, caused by Stemphllium solani, so I don't know if it is what you have. I do know that it can resemble the early spring damage you see from flea beetles, because tissue necrosis occurs in the center of the specks, giving it that shot-hole appearance, and I think you said you were seeing some of that, so you may have Gray Leaf Spot.

    WHAT DOES ALL THIS MEAN AND HAVE WE FIGURED IT OUT?
    I have no idea. The green tomatoes that have had that rash area probably have Bacterial Spot. You can rule in or rule out Bacterial Canker by inspecting the stems as i described above. If it is Bacterial Wilt, you can diagnose it by suspending the cut stem in the glass of water and watching for a discharge, as described above. I still lean towards thinking it is Fusarium Wilt but also with perhaps Gray Leaf Spot and/or Early Blight.

    I am pretty sure it is NOT Southern Blight (instant wilt of seemingly healthy green plants followed by a white mold on the stem and surronding soil). I've only had Southern Blight on one plant here in ten years. Pretty sure it is too hot here for it to be late blight, and when you have late blight you generally see white mold on the leaves and late blight spoils the fruit too. The symptoms don't match anthracnose although you do sometimes see anthracnose on fruit AFTER EB has severely defoliated and weakened the plants. I assume it isn't any of the soil rot diseases since your tomatoes are fine, except for the smaller, newer ones that don't develop properly.

    You could go to the OSU Fact Sheets and look at the photos there if you haven't already, but like I already said, the real-life stuff I see in my garden doesn't compare well to photos because in real life you often have a mixture of several sets of symptoms.

    Long ago I printed the three OSU Fact Sheets on Common Diseases of Tomatoes, and I have read them and looked at them so many times that I feel like I could probably recite them from memory. They are
    Common Diseases of Tomatoes Part I. Diseases Caused By Fungi (F-7625)
    Common Diseases of Tomatoes Part II. Diseased Caused By Bacteria, Viruses, and Nematodes. (F-7626)
    Common Diseases of Tomatoes Part III. Non-Infectious Diseases. (F-7627) I sort of disagree with their title (but they are the experts and I am not). What they call non-infectious diseases is what I think of as mostly physiological disorders, but that's just me.

    For all the issues in the first two factsheets, the only "solution" is prevention. Once you have bacterial and fungal stuff in your soil, it is usually there forever. Sometimes you can kill it will solarization. It used to be you could fumigate with something like Vapam, which is no longer on the market, but I don't know that it was all that effective back when people used it, and as an organic gardener, I wouldn't have used it anyway.

    If it wasn't for bacterial and fungal disease, which I tend to refer to "foliar issues" in general, everyone in the USA would have a row of tomatoes in their backyards. If there is anything that discourages gardeners to the point that they give up growing tomatoes, it probably is foliar issues and nematodes.

    Dawn

  • 18 years ago
    last modified: 11 years ago

    Thank you, Dawn for all that information.

    It's depressing, though.

    I've been thinking about trying solarizing the soil. I guess August would be a good month to do that. I hadn't planned on saving any seed, but I did save seed from last year (which I didn't plant because I was trying some other kinds). I guess I'll have to throw them away, because I had this last year, too.

    I can't solarize the one raised bed, because it has asparagus growing in it, as well as the tomatoes. And the third bed is full of sweet potatoes and beans, and just starting to put on cucumbers. So there's just the one bed I can solarize now.

    Here's my plan, and tell me if you think it will work. I'll clean out all the tomato plants and solarize the one bed. Then just plant tomatoes in that one next year. I can plant beans and other things in the bed that has the asparagus in it next year. I don't quite know what to do about the third bed, I can't really solarize it in August because I've got beans, cukes and sweet potatoes growing in it and I don't think the sweet potatoes will be finished in time to take advantage of summer's heat to solarize the bed. But maybe since it has no tomato plants in it now, do you think I could plant some of my fall tomato plants in there and just hope for the best?

    I only have the three raised beds so it's really hard to rotate. I usually have two raised beds full of tomato plants. If I would settle on just one or two kinds of tomato that do really well for me, I could probably cut it down to one. This year, I had about six plants that didn't bear any fruit at all.

    On top of all that, while I was out inspecting the tomatoes, I noticed a stink bug. In fact, I saw 2 or 3 while I was out there, and I don't know if they are the culprit, but a lot of my beans have round holes in the pods. Since I'm growing one particular plant for the seed, this is going to be a problem. While I was watching them, one buzzed off and lit on the peach tree. They are brown and shield shaped. I Googled "stink bug" and found out they will eat anything and will actually get into your house to winter over! Oh, gosh, that's a scarey thought. Last year, I had some on my zucchini but I had harvested enough of them so I just tore the zucchini plants out, and I didn't see any more stink bugs after that. I've never really thought of stink bugs as much of a threat before, because once I got rid of what they were eating on, I wouldn't see any more of them. I had never heard of them getting into the house until today and now I'm kind of freaked out. So do you know anything I can do about stink bugs?

    Gee Whiz!! It's a good thing our survival this winter doesn't depend on my gardening success.

  • 18 years ago
    last modified: 11 years ago

    Photo #3 looks like debris left from a pest and or a pest. I recommend looking at it with a hand lens. Not all pests slap you back when you go looking for them. Some can be hard to see unless you really study very closely.

    randy

  • 18 years ago
    last modified: 11 years ago

    Ilene,

    August would be a great time to solarize since is is ultra-hot.

    I think you could use the third bed for tomatoes next year, but remember that these diseases, once present, never really go away and can spread from bed to bed via tools, insects, soil splash, etc. Once they are present in your soil, good fall clean-up, heavy mulching, drip or soaker hose watering, etc. are all you can do. You can spray with a preventive product, but most of them are only marginally effective. Daconil is probably most effective of all the chemical treatments, but I choose not to use it because I can get a decent crop most years without it. Some people have good results with organic sprays, but others don't.

    For stinkbugs, there's mot much you can do. I don't know of any really effective chemical or organic pesticide, although I haven't tried Serenade on them. Some people (and I'm guessing they only have a limited number of plants) wrap their entire cages in summerweight floating row cover tied together at the top to keep the stinkbugs and leaf-footed bugs off their tomatoes. (I'd love to do that if I had only a handful of plants.)

    Some people vacuum them off with a handheld vacuum, and some use a shop vac if they have a long extension cord.

    You can handpick them and flick them into a bowl of soapy water and drown them.

    You can knock them off the plants and squish them with your shoe, grinding them into the ground, but they will emit a foul odor. (I don't care! I hope every other stinkbug in the area smells that odor and leaves!)

    The hotter your climate, the worse they are. They are worst here, normally, in our hottest weather and the earlier it gets hot, the earlier they show up.

    A lot of people in Texas, especially the southern half of Texas, just give up and abandon their tomato plants to the stinkbugs once the bugs arrive because they have them there in tremendous numbers.

    Some people spray the plants with Surround, a kaolin-clay based barrier type product. I've never tried it. I know research has shown it protects certain crops from certain pest, but I've only seen anecdotal reports on using it to protect tomatoes from stink bugs.

    And I agree with Randy that Photo 3 has some pest thing going on, but I haven't had anything like that kind of white debris, except when I have spider mite webs and other insect debris gets caught in the webs.

    I have stink bugs pretty much every year, and had leaf-footed bugs for the first time last year. The stinkbugs have never tried to come into the house to overwinter (unlike the lady bugs). I would think that the stinkbugs would be easy to vacuum up if they make it into the house.

    I need to do some more research on stinkbugs because they are becoming a worse problem every year. Surely there must be SOMETHING which preys upon them and I need to figure out what it is. Most years, they arrive here in late July or in August. This year, they arrived in May and I've had about all of them (and their damage) that I can stand. I've got both the green ones and the brown ones.

    Dawn

  • 18 years ago
    last modified: 11 years ago

    Well, Dawn and Randy, I went out this morning and cut each tomato plant down to about six inches of the stems. This is only because DS will be mowing the back yard in the next day or two and I don't want him to have to deal with tomato cages laying all around.

    As I was cutting, I still did not see any webs. I did find one red tomato that had a dark spot on it about the size of a head of a pin and a narrow white ring around it. But I didn't see any of those spots on any of the other tomatoes. Some of the plants I cut down did have blossoms and tiny tomatoes at the very top of the vines, but I knew it was pointless to leave them to mature. Looking at the pile of tomato vines waiting to be loaded into a garbage can, I can see that all the tomato plants are over 75% brown. I think that I just must have a lot of things going on.

    Picture number 3 that looks like some kind of aphids or something on it, is kind of misleading. That's white flecks that are catching the sun, so that makes them look wet in the picture, but they're not. I've looked at it through a magnifying lense and it's like a white power. HOWEVER, on another leaf I saw, through the magnifying lense, several tiny, tiny brown things -- maybe spiders. They were moving around.

    So! Do I have every possible disease AND pest on my tomatoes? I would much rather have a pest than a disease, as the pest is probably easy to eradicate. As I was cutting, I noticed some of the vines were brown and gooey inside, at least the ones that were showing some signs of trouble on the outside. The healthy-looking ones just looked light green in the inside.

    I have not yanked anything out yet, so if this newest revelation sounds hopeful and there's something I can do, I might try treating them and letting them come back from what's left of the vines.

    I'm so glad to know that you've never had stinkbugs invade your house. I had never heard of that happening, and when I was a girl we used to get stinkbugs whenever we had squash planted. --Ilene