I pulled a couple of leaves off and brought them indoors to take a pic. It was still dark when I Ieft the house this morning. Sorry, the pic is a little blurry. The little specks have grown into bigger specks. (these potatoes were planted on St. Patrick's Day, so they've only been in the ground for a little over 2 months.) Do I need to spray with something?

In the photo it is not clear if the brown spots are evenly brown in color or if there are concentric rings within the brown spots, and knowing whether or not there are concentric rings could be key to determining which disease your plants have. Take a close look at the brown spots and see if you see concentric rings similar to a bull's eye pattern. There will not be much variation in the shades of brown of the different rings, but if rings are present, they usually are obvious. If you do see concentric rings, then the plants have contracted a disease called Early Blight, which is a common airborne disease of solanum family plants, including tomatoes, potatoes, peppers, eggplant and tomatillos. If you don't see concentric rings, it still could be Early Blight but it also might be something else that is either fungal or bacterial in nature.

Diseases of Irish Potatoes

If it is not Early Blight (Alternaria solani), it could be Alternaria Canker, which is related but different. With Alternaria the spotting often is more angular than circular and you don't see the bull's eye pattern. Be sure to also look at the stems of your plants to see if you see brown spots on them.

If it isn't one of those fungal diseases, it could be a bacterial disease like bacterial speck or bacterial spot. Both bacterial speck and spot are more common in my garden in cooler, wetter weather whereas Early Blight is more common in alternating warm and cool wetter, and then the warmer and wetter we get, the worse the EB gets.

Once you have these diseases present, you cannot get rid of them. All you can do is try your best to keep them from spreading and killing your plants, and from spreading to your other solanum family plants.

For any fungal disease, the standard recommendation is to remove every infected leaf (if possible---if they all are infected, you obviously cannot remove them all). Take care not to spread the disease from one plant to another while doing this, which generally involves washing your hands when moving from one plant to another. Then, following the label directions, spray the plants, aiming for coverage of all stems and both the tops and bottoms of leaves, thoroughly with a fungicide labeled for use on potato and tomato plants with fungal diseases. The ones you most commonly find in stores have the active ingredient chlorothalonil and it is found in many products. One of the most common ones is Ortho Disease Control with Daconil (a trade name for chlorothalonil). It comes in a red plastic bottle and comes in both a RTU spray bottle and in a concentrate you mix up in a tank sprayer. To keep the disease at bay, you'll need to spray regularly following the label directions, which probably call for spraying at 7-10 or possibly 10-14 day intervals. (I don't spray Daconil often enough to remember what its interval is.) Another common fungicide is Mancozeb, although I've never used it and don't know if it is as effective on Early Blight as Daconil is.

If what you're seeing on your plants is not Early Blight or Alternaria, then it probably is bacterial in nature and the standard treatment for that would be to spray with a copper fungicide. I don't know the names of any of them, but it would clearly say copper on the label, including in the list of active ingredients.

Because diseases can develop a tolerance of or a resistance to both chlorothalonil and copper sprays, the best method of spraying is to use them alternately to help prevent the tolerance/resistance from developing.

Potatoes, tomatoes, peppers, eggplant and tomatillos all are susceptible to the same diseases and the month of May is when the diseases usually really start to show up here, especially if the weather has been wet and humid.

You can look at the diseases on the webpage linked below from the TAMU Tomato Problem Solver. I realize that we're talking about your potatoes, not tomatoes, but the diseases are the same on both plants. And, if what you have is fungal in nature, you need to treat all the solanum plants in your garden ASAP in order to hopefully prevent it from spreading from one plant to another. On the problem solver page, click on the photo of each disease to go to a full page with larger photos and a description.

TAMU Tomato Problem Solver-Leaf Pages

One reason you remove the diseased leaves is to prevent fungal spores from going airborne and transferring the disease from one plant to another.

It can be very hard to diagnose potato and tomato diseases because often you may have more than one disease sort of pop of all at once....like, when you've had weather that's been wet and humid for days on end. I find it easier to diagnose diseases in my own garden when I have been able to watch the change in the leaves from day to day as the symptoms appear. It is a lot harder to diagnose someone else's disease issues based on a photo that captures one moment in time.

Fungal diseases and bacterial diseases usually start on the lower leaves (often because the disease spores were splashed up from the soil onto the lower leaves by rainfall or irrigation) and move up. Often the first clue is that the leaves turn bright yellow and then the brown spots begin to appear. They are much easier to prevent in the first place by spraying the plants regularly with a fungicide from the first week they sprout (potatoes) or are transplanted (tomatoes, peppers, eggplant, tomatillos) into the garden. They are impossible to 'cure' once the plants have them, so all you can do is try to control them so they don't spread rampantly. Spraying regularly with a fungicide can help the plants survive long enough to produce a harvest, which is about the most you can hope for after it appears in your garden. Regular spraying with a fungicide, mulching to prevent soil splash, etc. can help prevent the diseases, but generally at some point (usually in May's wet weather) they pop up anyway. Fungal diseases of solanum family plants are found worldwide and it is almost impossible in our climate to have a garden that is free of them, particularly since the spores go airborne quite easily.

I haven't been out to my garden yet today, but I bet when I go out there, I'll find something similar on my potato plants. After nonstop clouds, drizzle, rain, fog and dew for the last week, the bigger shock would be to go out there and to not find some little disease rearing its ugly head.

I do want to add to what Keith said about potato plants rapidly going downhill as the plants approach maturity. For those of us who planted our potatoes in mid-February, that can happen as early as mid-May depending on the variety planted. Sometimes it doesn't happen until June with the potatoes that have longer DTMs. Because you planted your potatoes in March, I'm slightly more inclined to think you're seeing a disease than to think you're seeing the approaching signs of maturing plants that soon will die back, but sometimes my plants have fooled me and appeared to be diseased when really, they had begun their natural process of dying back.

So Hazel, I went out to my garden and looked at my potatoes after thinking about yours and contemplating what the yellowing and the brown spots might be.

I have some potato plants that look great. I have others that have only a little bit of yellowing of the foliage (and it likely is the earliest stage of Early Blight) and then I have some in another area that have a lot of brown spots and specks on the foliage. And some of them clearly have Early Blight and others have Bacterial Spot and some have both. I guess I'll spray tomorrow in an effort to keep it from spreading.

The tomatoes, tomatillos, and peppers look fine for the most part, but that is because I sprayed them with Daconil last week (it might have been Saturday, or it could have been Sunday) in an effort to prevent diseases from popping up. I also sprayed all the beans because some were showing early signs of rust. So, everything looks good except for the potatoes, and for the life of me, I don't know why I didn't spray them. Usually, if I go to all the trouble to buy a bottle of Daconil and drag out the sprayer and use it, I spray everything, but for some reason this last time, I apparently didn't spray the potatoes, so their crappy appearance is all my fault for not protecting them when I knew they needed it. And, joy of all joys, after a couple of nice weekend days, we have a chance of rain in the forecast for every day next week, because that's exactly what we don't need to have happen.

Alrighty, I picked up some Daconil and sprayed most everything in my east garden. It's a little difficult to wash your hands after picking off each leaf when you have a hundred leaves to pick off. I just sprayed everything and my gloves too.

I also purchased a copper product--the label says it's also good for blight. It also says for organic gardening, but the Daconil does not say that. So...I have a back garden too and only one tomato plant shows any signs of having something..and it's not much--just a couple of spots. It could be something else, but I sprayed it too. Would you suggest spraying EVERYTHING in the back garden with the copper/organic gardening product as a preventative?

Is spraying fungicide something most gardeners do as a preventative? I need to know this for next year. My green beans and even the squash seedlings all seem to be suffering from something. They are stunted. They got sprayed. I'm even thinking of pulling out the squash seedlings and putting some others in (seeds). Or should I wait until after next week when the rainy week is over.

Dawn, what sort of sprayer do you use? I just bought a bottle with a spray on it, but the stream is rather narrow and I would like a wider, softer spray.

My potatoes look great, except for flea beetle holes, but some of the tomatoes are less than stellar. Removed ugly leaves and plan to get some fungicide this afternoon. I've left a few pea plants, but this last week of rain mildewed them bad. Can you eat the peas inside if the pod is mildewed? Can the chckens eat the vines? I need a few days of dry weather!

Hazel, It is exceedingly difficult to remove leaves and avoid spreading the fungi from one plant to another, but I really do wash my hands in between plants. If there is anything worse than having 1 plant with early blight on it, it is having 100 plants with early blight. Often, I keep a container of wet wipes in my tool bucket, and use a wet wipe to clean my hands before I move from one plant to another. I can run through a container of wipes in the blink of an eye in the garden, but I do think it helps slow down the spread of fungal spores.

Copper is organic, but you have to be very careful not to use it too often because the copper can build up to toxic levels in the soil and that is bad for your soil and your plants. Daconil is synthetic, not organic, and I have a love-hate relationship with it. For about our first 15 years here, I didn't use it, even when I knew that disease was running rampant and that I needed to use it. A couple of years ago, I used it somewhat regularly and slowed down the spread of Early Blight enough that my plants survived it and eventually outgrew it when we got hot enough. Since then, I still cannot make myself use it as often as I should. In order for preventive fungicides to be really effective, they need to be sprayed regularly from the first day your plants go into the ground. Since I don't like spraying anything on my plants and I don't like eating things that have been sprayed, I often don't use it at all. Or, I'll spray once or twice when Early Blight first starts up and then not spray any more. Still, as synthetics go, it is not a bad one. It is not systemic, so the fruit, for example, does not absorb Daconil into it and then feed that Daconil to you. (I do not use anything that is systemic.)

If you want to stay 100% organic, you could use Serenade instead, but I don't think it is nearly as effective as Daconil. The way that preventative fungicides work is that you completely coat the plant stems and foliage with them, and the spores cannot attach to the plant. That's in a perfect world. Here in the real world, it is almost impossible to get the top and bottom of every single leaf, so you'll still have places you miss and Early Blight is likely to find them and attach to the leaves or stems in those spots. However, by spraying, you slow down the spread of the disease very drastically. The very first time I tried Serenade, I thought it was wonderful and amazing. But then, after the fact, looking back at the year in which I used it, we had drought and very little rainfall during the growing season, and the dry conditions probably had more to do with how effective the Serenade seemed to be because in a wetter year, it didn't seem at all effective at slowing the spread of disease.

I prefer to garden as organically as possible. However, Early Blight can devastate a garden in the blink of an eye, so I've learned that if I ignore it when it first appears or don't do at last some minimal treatment to slow it down, my garden will produce really poorly. Given the choice between a mostly organic garden of plants fully loaded down with fruit, or a 100% organic garden filled with half-dead plants that produce poorly, I choose to use the Daconil. This is a fairly recent development, and I'm not in love with the idea of using chlorothalonil, but I am trying to make the best decision for the garden. I try not to get too hung up on the concept that everything organic is good and everything synthetic is bad and try, instead, to make wise choices of whatever I use in the garden, whether they are organic or synthetic in nature. There are plenty of organic pesticides, for example, that are much more toxic than Daconil and I'd never ever use them---haven't used them in 57 years of living on this planet and don't intend to ever use them---and I'm talking about things like Rotenone and Sabadilla. What I try to avoid most is synthetic pesticides...whether they are insecticides, miticides, molluscicides or whatever because so many of them are nerve poisons, insect growth regulators or something similar that I don't want to live around. Using synthetic fungicides doesn't bother me nearly as much as using pesticides would. Using synthetic fertilizers also doesn't strike me as the worst thing on earth either. I also like to look at the EIQ of various products and choose the products with EIQs at the lower end of the scale, whether they are synthetic or organic in nature. Too many people think everything synthetic is bad and that everything organic is good, but real life just isn't that simple. There are some great synthetic products and some horrible organic products, and it has taken me a long time to truly absorb that lesson and learn it well.

I do not use herbicides of any kind, not organic and not synthetic and feel like there's no place in my garden where the use of herbicides outweighs the risk.

Because I grow tons of tomatoes and peppers every year, the choice to spray my plants from 1 to 3 times a year with Daconil is a decision based on seeing how quickly the plants have gone downhill in wet years when I didn't use Daconil. There is just no comparison between the performance of plants when sprayed with Daconil versus when not sprayed with Daconil. Because I only use it 1, 2 or 3 times a year, the EB eventually will win anyway, but by then I will have done all my canning and won't mind if some of the plants die. In the few short years I've used Daconil, I've generally sprayed once or twice in May and once in June. After that, either the weather has stabilized and dried out and the Early Blight doesn't seem to be spreading as much, or I'm just tired of fighting the rain and don't want to spray any more.

I have a pump-up tank sprayer. You fill it to a certain line with water, to which you add the proper amount of the fungicide. Screw on the cap, shake up the sprayer to mix the fungicide and water together, and pump the handle as required to build up pressure. I'll link a sprayer similar to what I use:

Example of a Pump Sprayer

Whether to spray preventively or not is a decision each gardener has to make for himself or herself. Like I said previously, for roughly our first 15 years here, I just didn't do it. I might have sprayed Daconil one time in all those years. Not spraying meant that no how beautiful and productive my tomato plants were in mid-May, it was inevitable at some point they would get Early Blight and, once that happened, they would look like crap and productivity would really drop. Because I didn't spray for so long, I got used to seeing it appear around the third week in May (though often not a heavy infestation until around the third week in June) and within a month my plants would be tacky, horrible-looking, sad and pathetic shells of their former selves. Eventually, I got tired of getting that sinking feeling of "oh no, Early Blight is here...." and decided I'd try to spray when it first appeared in an effort to keep it from spreading. Then, if needed I'd spray a second time two weeks later, and if needed, another couple of weeks after that. Sometimes I only spray once. Sometimes it is twice or three times. Now, clearly I am not spraying as often as I should. I think they recommend you spray every 7-10 days for as long as needed up to a maximum number of times per year (I don't remember what it is). Generally for me, though, 3 times is about as much as I'll spray. Does it make a difference? Yes. Last year we had 24" of rain in May and another 12" in June and my tomato plants were soaking wet literally every single day of those two months. The fact that they survived at all (and produced very well) is solely because I sprayed them enough with the Daconil to keep the Early Blight under control. I am just at the point in my life where I'd rather have living, fairly healthy and productive tomato plants sprayed with Daconil than to have dying, non-productive and ugly tomato plants that never have been sprayed with a synthetic fungicide.

I've tried to blame the Early Blight on the fact that my garden has always had tons of tomato plants in it, from about 35 plants my first year here (1999) to 600 plants in either 2005 or 2006. You cannot rotate tomato plants to a place where tomato plants haven't grown in the last 3 years, because I grow tomato plants everywhere. However, in very wet years like 2004 and 2007 when I grew in fresh, sterile soil-less mix in containers well away from the fenced garden, the plants got Early Blight anyway. In the first year we used the back garden and planted tomato plants where no tomatoes ever had grown, we had Early Blight. It is in the soil. It is in the air. Its spores go airborne quite easily. I think I could grow a tomato plant indoors that never got a whiff of outside air and it still would develop Early Blight because spores would come indoors when we open a door to walk in or out. So, since Early Blight is so common (it is an issue worldwide), the issue becomes how you deal with it, and it is much easier to deal with it by preventing it than by struggling to contain it once plants are covered with it. Every time you remove leaves that are infected, you're exposing fruit to more sunlight and to sunscald, so it is imperative to stop its spread before it infects the plants too heavily. I got tired of having to strip infected foliage off my plants weekly in May and June, so I started spraying, and that's the right decision for me.

Hope this helps,

Dawn

Amy, I don't know the answer to your questions...but noticed some faint white stuff on my peas too! I'm just now starting to get good harvest from them, so I hope they're safe to eat.

Sorry about your tomato plants. Mine really look pretty good, but I don't have fruit yet except for two. They do have blooms.

I'm really sad about my potatoes and squash and beans.

Amy, Once the mildew starts, I don't eat them. You probably can eat them if the mildew hasn't spead inside the pods yet.

Honestly, though, once the powdery mildew hits the plants, I take that as a sign from God that the growing conditions now are too warm and too humid for the peas and I yank them out and replace them. Once the powdery mildew starts, you aren't going to be able to stop it and you don't want for it to spread to other plants in your garden. At the very first sign of PM on the lower leaves of my pea plants I did one last big harvest and then yanked out the plants, replacing them with pole snap beans and pole lima beans. The pole beans are now happily climbing the trellis and perfectly happy and I' glad I got the plants with PM out of the garden before the PM could spread.

In general, our chickens do not eat peas or beans of any type, though some of them will eat bean plant foliage. I don't give diseased plants to the chickens. I just don't see the purpose in giving them something that is poor quality like that. Diseased plants belong on a hot compost pile that will kill the disease microorganisms during the composting process, or they should be bagged up and disposed of in the trash. You don't want to leave any diseased foliage lying around where it can continue to spread the disease via airborne spores, water, soil splash, etc. Good garden sanitation can prevent a lot of disease issues from spreading and taking over a large portion of the garden.

Dawn

The peas were definately past their prime. We ate some last night and they just tasted too mature, not as sweet as they should. Only a few pods had started to look bad and I passed on the ones that were real bad. Tomatoes are already planted in that bed, the peas will be gone today. Uncooked beans are supposed to be bad for chickens. (The dried kind. Don't know at what point they develope the chemical that causes the problem.) Some people feed leftover cooked food to chickens. Does anyone do that? Seems like that would be asking for a pest problem.

Hazel, last year I slowed the mildew down with milk. 10% solution sprayed in full sun (sun is important). It just rained too much for my schedule this year. And the Sugar Annes were the first and worst. Might have been their position, but I think they're off my plant list. I also have a Garden Safe brand fungicide that says it's for mildew, but I can't say anything worked for long.

I know milk requires strong sunlight. What about daconil? Don't really want to spray it and have it burn, but wetting plants too late in day is supposed to be bad, too. Didn't find anything in the instructions. I'm thinking 5 pm? Now I have beans to plant that are way too late.

Thanks, Dawn and Amy. My biggest concern (or at least one of them) is killing the beneficial insects or ruining my soil. But I'm looking at a partially sad garden right now when it was so vibrant last week. My neighbors garden looks amazing. She's already harvesting first zucchini and summer squash while I'm watching mine all stunted and sad trying to make it's first real leaves. (I did question their planting at the first of March--I was just sure we would get a freeze)

Does the fungicide affect the insects?

Maybe this was a learning thing for me. At least it happened this year when my kitchen is fixin' to be torn apart...and my pressure cooker and freezer are lost and/or unaccessible. But the tomatoes and peppers can be water bathed, right? If they make it.

Amy, The use of a milk spray requires strong sunlight? I've never sprayed milk in my garden and likely never will. I am not a huge fan of homemade concoctions because I have seen so many people damage plants with them. I pretty much completely avoid them, other than the use of compost tea for about a decade, and I don't even spray it on plant foliage any more. I still sometimes use it as a soil drench.

With synthetic preventive fungicides like cholorothalonil, users are advised to avoid spraying in strong sunlight and hot conditions, so I always spray during the coolest part of the day, generally when it is cloudy, and often just a few hours before rain is expected to fall. While they advise that we avoid spraying in hot, sunny conditions, they do not define "hot", so I just try to spray either first thing in the day just as the sun has come up, or on a cloudy day when the weather is relatively cool, or in the evening when sunset is not too far away and my garden already is largely shaded and cool. I've only used chlorothalonil a very limited number of times and only in very recent years, but I've not had any issues with it burning plant foliage.

Based on a lifetime of experience in spraying various (mostly organic) things in/on my garden, I never spray in sunshine when the temperatures are at 80 degrees or higher---I either wait for a cloudy day, or spray in the coolest part of the day when there is no direct sunlight hitting the plants. So far, that method has served me well.

Hazel, There are three kinds of fungicides available to a gardener: organic, synthetic preventives like chlorothalonil that are NOT systemic, and stronger fungicides that ARE systemic. This is an important distinction.

1. Organic types. Organic fungicides are widely believed to be safer for the plants. I do not doubt that in some way this is true, but what I have found through trying to use them on solanum family plants for Early Blight and for Alternaria Canker is that the organic ones are not very effective. As a person who tries to garden in the most natural, most organic and most sustainable way possible, it pains me greatly to say that, but it is the truth as I have observed it in my garden. If the organic fungicides were superior, I'd use them. If they worked well at all, I'd use them. I just haven't found that they are very good at preventing or controlling the two diseases that tend to hit my tomato plants every year, so if they don't work, what's the point in using them?

A totally organic approach is great if it works, but not great if you let the same disease hit and kill your plants every year because you won't use an effective method to stop that disease. Because the organic fungicides are not very effective, they must be sprayed much more often than the synthetic preventive fungicides. The more often that you spray, the more likely you are to burn or otherwise damage plant tissue. So, I finally wised up and decided it was better for my garden if I decided to move on from the organic fungicide and use something that actually would work. It was either that, or sit by each year and watch as Early Blight hit and destroyed a garden full of beautiful, productive tomato plants. There just didn't seem to be any point to me in spraying organic fungicides that were ineffective, especially if I had to spray them more often. You know that I hate spraying. So, rather than spraying an ineffective organic fungicide, for very many years I sprayed nothing and just let the Early Blight decimate my plants for far too many years. Well, I'm through with that approach too. What good is an organic garden if diseases impact it to the point that the tomatoes don't produce? So, I moved on from the organic fungicides to the next category.

2. Synthetic preventive fungicides that are not systemic in nature. I think the word that the scientists use for these types of fungicides is "protectant". These types of fungicides work by coating the foliage, thereby not allowing the disease microorganisms to attach to the plants and infect them. The plants do not absorb these protectant fungicides into their tissue (which is how they differ from systemic types) and in order to avoid eating the fungicide, all you have to do is thoroughly wash your harvest before eating because the fungicide stays on the surface of the plant and all its parts. (This is assuming you follow all the directions on the packaging of your fungicide....for example, with some products they tell you that you must spray a certain numbers of days before harvesting. Guidelines like that should always be followed.)

These protectants are most effective if used from the very first day plants go into the ground. Because I prefer to eat food from plants that have not been sprayed, I've never actually tried this approach because I want to keep the amount of spraying I do to a bare minimum. What I will do is go ahead and put my plants in the ground, and then at the first sign of Early Blight, I strip the infected foliage off each and every plant and then spray the plants with the protectant fungicide. If I have caught the disease early, I often only have to remove diseased foliage from a few plants. This is a somewhat less than perfect approach because it means the disease is already present before I ever spray. I understand that, but it makes me happier to spray as little as possible so I don't spray from Day 1. I generally don't spray until Early Blight shows up, and that can be anywhere from late April to mid June.

Given that I put plants in the ground in mid- to late-March, and our season runs for many months, I choose not to spray from Day 1 because I want to use as little of the fungicide as possible. I've never sprayed chlorothalonil more than 3 times in one year. If I remember the label correctly, I think they recommend a maximum spraying routine for tomatoes of 7 sprays over the course of a season. If a person sprays every two weeks, at that rate they could use a fungicide for 14 weeks. I know people who spray a lot more often, though many of them are in cooler (and wetter) climates than ours, and they likely have less fear of the repeated use of fungicide sprays possibly damaging their plant foliage since they rarely if ever have to deal with the kind of extreme heat and sunlight we have here in the summer months. They also understand that spraying more often or more times overall is not recommended, and they know they are spraying at their own risk if they spray more times overall or more often than the label recommends. Most years I only spray a protectant fungicide once or twice and use it to slow down the spread of disease just long enough that I get my big June/early July harvest for canning. After I've canned a few hundred jars of tomato products, the diseases can just go ahead and have the plants if they still want them because by then I am sick of tomatoes.

There are many different kinds of protectant fungicides. Some of them are recommended for tomatoes, while others might be recommended for fruit trees or ornamental plants. Because chlorothalonil is considered very good as a protectant against the disease that plagues my tomato plants, it is the one I've chosen to use. I haven't used the other synthetic types, so cannot really comment on any of them. Some of the other protectant fungicides available include Captan, Mancozeb and Thiram. I've never used any of them, other than occasionally purchasing seeds that were treated by the wholesaler or retailer with thiram.

One key thing to remember about protectants is that diseases do not develop resistance to them, or at least that is how I understand it. Since the protectants are only serving as a barrier between the plant surface tissue and the disease, these diseases don't develop resistance in an effort to overcome the protectant. All that the diseases have to do to succeed is to find one tiny spot where you didn't spray the protectant on the plant foliage (and there's always going to be places that the spray misses), and they can overcome the protectant, so there's no reason for them to develop resistance. That's important.

Finally, protectants only work by sticking to the plant surface. When washed into the soil, they degrade and break down. They do not harm the microbial life in the soil.

3. Synthetic fungicides that are systemic in nature. I've never used one of these, and I do not believe I ever will. Unfortunately, these are widely used in commercial agriculture and have been in use since the 1960s.

Systemic products are absorbed into the plants and work by moving through the plants' vascular systems to offer protection to every plant part. Unfortunately, once they are in the plant, that means they are in the part of the plant we eat. That's why I won't use them. There are different kinds of systemics and some work differently from others, but the thing to remember is they absorb into the plant and become a part of it.

It is interesting that some research may show that the systemic fungicides harm some of the biological life in the soil, but other research may show that the use of some system fungicides actually increase the mycorrhizal infection of plants. This ought to be considered a good thing, I suppose, as the mycorrhizae fungi are beneficial fungi that live in the soil and normally infect your plants but do so in order to help the plants take up nutrients in the soil. I do not know which systemics cause more mycorrhizal infection versus which systemics cause less, but if I were using a systemic, I suppose I would want the one that stimulates more.

Systemic fungicides often are favored by growers for several reasons, including the fact that they have some degree of curative ability, while non-systemics are not curative, only protectant. Also, many systemics provide a longer period of protection than the protectants do, so they can be applied less often.

The most important thing to know about using a systemic fungicide (other than the fact it is absorbed into the plant and remains there) is that diseases will and do develop a resistance to these types of fungicides, giving rise eventually to fungicide-resistant fungi. Thus, if using this type it is very important to always select 2 or 3 of them to use in rotation in an effort to prevent resistance from developing in the first place.

I suppose I've never looked for these products on store shelves, so have no idea if they are readily available to a home gardener, but am familiar with a couple of the names and do know some people who use them either on their farms or in their home or market gardens. Among the types of systemic fungicides available are benomyl, myclobutanil and tebuconazole.

So, that's pretty much everything I know about fungicides. And, I'll add, that it is my understanding that some systemics are not labeled for use on edible plants, so anyone who chooses to use this type must be sure to buy one labeled for use on whatever sort of plant they're intending to spray with it.

There are other ways to somewhat control fungal infections in a garden. It is helpful to always mulch the soil around plants, including adjacents pathways, to prevent rainfall from splashing onto the ground and carrying fungal spores (or bacteria, as far as that goes) up onto the plants as the raindrops bounce up off the ground. The thicker the mulch, the better. I try to start out with an inch of mulch at planting, and increase it over time up to 2-4", though the thicker mulch is more to keep the ground cool and moist than anything else. Also, fungal infections generally start low on the plants, on the leaves closest to the ground. So, as my tomato plants get bigger and bigger, I remove the very lowest leaves. Usually, by the time I see the first sign of Early Blight, I don't have any leaves that are close enough to the ground to touch the mulch or the soil if there wasn't any mulch there. Once you have disease-infected lower leaves, it is imperative to remove them because, if you don't, the disease microorganisms will spread more quickly, moving progressively upward from leaf to leaf.

Because Early Blight and other similar fungal diseases can be found in many places...in the soil, in the air, and even in raindrops, it is almost impossible to raise tomato and other solanum family plants without having Early Blight appear at some point in the season. I know plenty of gardeners who have given up growing tomatoes because they have become so frustrated by having to deal with Early Blight. I'm just never going to give up growing tomatoes. So, you have to have a plan in place to deal with it, and in order for the plan to be effective, you must execute your plan consistently and ruthlessly. For too many years, I tried an organic approach that failed. Looking back, I wish I had started using a protectant synthetic `10 or 20 years earlier than I did. While I still favor gardening in the most organic, most sustainable and most natural way possible, I am a realist and readily acknowledge that there are some garden problems for which the organic world just does not have a good solution. Tomato disease is one of those areas where there are not necessarily good organic solutions. So, if the choice is to use a protectant synthetic fungicide that will hold the disease at bay and allow me to harvest all the tomatoes we want, that's the choice I am going to make. I am just tired of getting that sinking sensation in the pit of my stomach when I see the first signs of EB in my garden. I know exactly how much damage it can do and how much it can decrease the productivity of my plants. In some cases, your plants can even die. I find it unacceptable to sit there and do nothing and let my plants die, and I find that using ineffective organic methods that don't stop the EB from spreading is tantamount to doing nothing. So, I've changed my ways.

And, I want to add this, while Early Blight and other similar diseases pop up virtually every year, I find that in drought years they are much less of a problem as long as I am watering in a way (like using soaker hoses or drip irrigation lines) that does not put water on the foliage. So, in drought years, you may see little to no Early Blight just because the weather conditions and your chosen watering techniques do not encourage its development and spread. I've never sprayed my tomato plants with any fungicide (organic or synthetic) in drought years because I don't have to.

Hope this info helps.

Dawn

Thanks for all the info, Dawn. I love it when you and others here share their gardening experiences with us who are fairly new to gardening. I know it's time consuming to type all that out, but I really appreciate it.

I did not mulch around the potatoes. I'm still somewhat confused about hilling potatoes and mulching. My husband said his dad (who did not use raised beds at all) just used straw...and kept adding it as the potatoes grew. So...if I mulch around the potatoes when they're small and then hill up dirt around them (do I put dirt on the lower leaves too as I'm hilling? Is that is what is causing the disease? You almost have to put dirt around the leaves) and then add more mulch on top of the newly added dirt--i"m just trying picture how that works. And how to avoid the soil touching the leaves.

My peppers and tomatoes are mulched. I was sure to mulch them because I remember y'all talking about about soil splash and disease. I used cottonseed hull. What's anyone's experience with cottonseed hull as mulch. It looks nice and tidy around my plants. Does it break down over the winter?

Hazel, Those of us here who have a little experience growing things are always happy to be able to share what we've learned with others. So much of what I've learned over the years has come from other folks on GW who post their experiences. Sometimes it wasn't that I learned something that really was new to me, but merely that I learned that other people were seeing the same things I was seeing and were dealing with it in the same way. That sort of validation is important too.

There is not, in my mind, much difference between hilling and mulching. I don't hill, but I do mulch. Let me explain.

As your potato plants grow, they form tubers along the stems. Depending on how deeply you plant, this might mean that the tubers form very close to the top of the soil, and if that happens, even little smidgens of sunlight can hit the potato tubers, causing them to produce a poisonous substance called solanine. You will know potatoes have excess solanine if the potato skin has a green tint to it when you look at it with the naked eye. So, to prevent the sunlight from even possibly hitting the tubers, farmers and gardeners hill up extra soil around the potato plants as they grow and form tubers. Now, that's the old traditional way of doing it. However, I hate hilling and don't do it and haven't done it in years.

An alternate method is just to use lots of mulch layered on thickly, often from 4 to 8" thick. (Not added all at once---you can add more and more as time goes on, just in the same way you hill up soil more and more over time.) The mulch can't be too fluffy which would allow too much light penetration, so it can take a surprisingly large amount of mulch, sort of well-packed-down, to provide the level of protection the potatoes need.

My preferred method for a long time was to trench plant---just dig a long trench down the length of the planting row. Dig it 8 or 9" deep, put the seed potatoes in the trench at the proper spacing, and then just put an inch or two of soil down in the trench to lightly cover the seed potatoes. After the potato foliage emerged and began growing, then you would rake more and more soil back into the trench. Eventually the trench was all filled in. One advantage of this type of planting is that you could watch your potatoes emerge and grow. And, once your trench was filled in, you could mulch to retard weed growth and your plants would produce just fine without sunlight hitting the tubers and causing solanine production. Any drawbacks to this method? It depends on your soil. It will not necessarily work in heavy, slow-draining clay soils because water can sit in the trench shortly after you plant, if it rains hard enough, and then rot your seed potatoes. Or, if voles, gophers or any other sort of rodent finds your trench, they can travel down the trench eating seed potatoes. Otherwise, though, in the absence of such pests and if you have well-drained soil, this method works fine. It worked fine for my grandfather and for my dad and for me for a long time. Until, suddenly, it didn't work for me any more.

In 2010 we had tremendous rain that filled my trenches and caused some rotting of seed potatoes even though they were in well-amended sandy-silty loam at the west end of the garden. I didn't know it then, but that was the end of potato growing as I once knew it. In 2011, we had the incredible early heat and drought that drove pine voles right out of the woodland and field areas and into my garden. We'd always had voles around, and they'd never bothered the potatoes. Not in 12 or 13 years of gardening here. The voles (unknown to me) traveled through the filled-in trenches and ate potato tubers that were forming on healthy potato plants underground, but since the trenches were all filled in, I didn't even know the voles were there. Apparently even once the trenches were all filled in, they still served as a little subway line that the voles traveled, eating their weight in potatoes as they traveled along the trench. Knowing I had met a potato opponent I never could defeat in the open ground, before the 2012 growing season we built hardware cloth-lined raised beds in which to grow potatoes. They are a couple of feet tall. Actually we built one the first year, and then a second one a couple of years later. This year we added a third. Next year I want to add a fourth and a fifth so I can have better root crop rotation. The hardware cloth lines the bottom of the beds and is stapled to the wooden boards that make up the walls of the beds. So far, the voles have not penetrated these beds.

The problem with raised beds involves how you plant within them. Since they are already raised up so tall to allow lots of growing space above the hardware cloth but below the soil surface, I didn't want to have to hill. Instead, I filled them with a really loose fluffy mix to which a great deal of compost was added. Now, when I plant, I dig down and plant my seed potatoes 9" below the soil surface and then immediately fill in the holes. The drawback to this method is you wait a lot longer to see your potato foliage emerge since the main stems must travel upward through 9" of soil, but the advantage is you don't have to dig trenchs, which would be difficult to do utilizing raised beds planted in a grid pattern instead of a row pattern. I think this year I planted the seed potatoes on 9" centers. Some years I have used 8" centers. I get really nice yields either way, and I like not having to fill in trenches or hill up potatoes.

Once the potato foliage emerges from the ground, I add a couple of inches of mulch that is comprised of either grass clippings or chopped/shredded autumn leaves or both. I generally don't add any more after that first mulching because the plants grow together in one big mass (an advantage of grid planting versus row planting) with no bare soil. They shade the ground beneath them which keeps down weeds anyhow even before I add much mulch, and they shade one another's tubers so no hilling is necessary.

I can get away with planting 9" down initially because my three raised beds sit well above grade level. No matter how much rain falls, the raised beds drain great. Well, not so great in last year's 24" of rain that fell in May, but that's not a normal rainfall month. Generally in May we get only 5-6" of rain at best, and the soil drains well enough to deal with that. Someone with heavier, more dense soil might not be able to plant as deeply initially and fill the trenches right in, but it works for me.

With hilling, you can use mulch instead of soil if you choose. There are a couple of reasons a person might not want to do that:

1) If you have any sort of rodents around who would live in the mulch---field mice, voles, rats, possibly gophers, etc., then the mulch can be a bad choice. One year a vole tried to raise a nest of baby voles in straw mulch I had around my flowers, and the cats wiped out that nest the minute they found it. A gardener without cats might have had more trouble with nesting voles than I have had.

2) If you have soil- or mulch-dwelling decomposers like pill bugs and sow bugs (and other creepy crawly things) that like to feed on root crops. This category might include wire worms, but they stay in the soil anyhow, not in the mulch. You can combat this problem if you have decomposers in your mulch by using an organic snail and slug bait like SLUGGO PLUS.

3) If you are using purchased hay or hay given to you by a local rancher, perhaps because it is too old/spoiled to use as livestock feed, you can accidentally bring in herbicide residue that kills your plants. The likelihood of this occurring is fairly high, and I've seen neighbors who are ranchers accidentally kill their own tomato and potato plants by using hay from their barn because they forget they purchased hay in a drought year. With purchased hay, you often don't think about the fact that the person who grew it may have used those persistent herbicides to kill broadleaf weeds and those persistent herbicides can persist in the hay long enough to kill plants, even after the hay or manure are composted. You can largely avoid this by using straw, if you can find it, but straw is hard to come by where I live whereas straw is very common. Or, you can only purchase alfalfa hay to use as a mulch for sensitive plants because alfalfa hay comes from a broadleaf plant that is a legume and not a grain, so it cannot be sprayed with the class of herbicides that cause herbicide carryover as they would kill the alfalfa.

I know lots of people who plant deeply and don't hill. I know folks who plant more shallowly and then do hill. Both tend to get acceptable yields, so it really is not so much how you do it, but merely that you find a way that works for you with the soil you have, the weather that you have, and the level of pest issues that you have.

One good reason not to mulch is that some pests, including Colorado Potato Beetles, can drop down into the mulch and hide from the gardener, if they happen to notice the gardener is walking along, handpicking and drowning CPBs. I mulch anyway. Even the CPBs that get away from me by dropping into the mulch and hiding still have to come back up out of the mulch to feed on potato foliage. If I don't find them and get them that day, I'll get them tomorrow.

I have to add this about Colorado Potato Beetles. They are easy to handpick and drown in a bowl of soapy water, but when I grew potatoes in the ground, I didn't even have to deal with them. We had a turtle who lived in the garden during CPB season and traveled up and down the rows eating CPBs. It worked all day every day until it ran out of CPBs to eat and then it pretty much went away for the season, returning occasionally to chomp on a tomato or melon. Once the potatoes were in tall raised beds, the turtle no longer could eat CPBs since it couldn't climb up into the bed safely, I removed it from the garden and plugged the spot where it used to crawl under the fence. I did that for its sake. One day I found it on its back beside a raised bed, and had no idea how long it had laid there waiting to be found and rescued. I guess it tried to climb the raised bed's boards, failed, fell, landed on its back and could have died there if we'd been out of town on vacation or something. I miss my big garden turtle, but the garden was no longer safe for it. We still occasionally get random small turtles in the garden, but not big ones like the CPB-eating turtle that roamed the garden for a little over a decade.

One added note about mulch: if you are rural or semi-rural and have an issue with snakes in your garden, particularly venomous ones, they really like to hide in the mulch. This causes me endless heartache, heart attacks and lots of fright. I am careful to always wear leather gloves while mulching, and I don't stick my hand into mulch to move it around. At harvest time, I use long-handled lopping shears to cut off the potato plants just above the mulch. I drop those plants into a wheelbarrow to cart off to the compost pile. Then I use a rake to rake all the mulch (and any snakes hiding therein) off the raised beds. Then, and only then, do I dig potatoes. All my friends who bet me $10 15 or more years ago that I'd never be able to garden here without being bitten by a venomous snakes haven't won that bet yet, for which I remain exceedingly grateful.

There also remains the issue about what you do with the mulch after harvesting. Since I use grass clippings or chopped leaves, I put them right on the bed if they are healthy and use them with whatever crop follows the potatoes. If the mulch were to be rapidly decomposing and have a "hot" feel to it (similar to what you see when you stick a garden fork into a hot compost pile), I leave it in a pathway and mulch the succession planting with new, fresh mulch.

So, to me it is not so important how you grow your potatoes---just don't be afraid to try different ways to see what works best for you. And, if the way you've done it for a long time suddenly stops working, figure out why and fix it. That's the difference in people who successfully garden and those who don't---the ones who succeed never stop experimenting, never become so "married" to one method that they won't consider doing it another way, and never stop trying to find a better way or an easier way or a more efficient way to do what they do. For me, the part I just don't like about hilling is that you keep disturbing the soil when you hill up, and disturbed soil tends to be full of weed seeds that only needed a fraction of a second of sun exposure to induce them to sprout. So for me, hilling gave me weeds I didn't want to deal with. It was just that simple.

Dawn

1

That's a lot of information, Dawn. I try to do organic, too, but I bought some Daconil, which I neglected to spray before the rain. (Grandson was here and I ran out of energy before I ran out of day). I have seen in other forums where people graft tomatoes on rootstock that is more resistant to disease. I have know idea how it works, and I haven't been interested enough to research it. Just a tidbit for any one who might be interested in going that route. I believe these people were battling late blight, which I guess is a more difficult disease.

Oh, the milk thing for powdery mildew. Here's a quote from this article: "Scientists are not exactly sure how milk sprays work, but most think proteins in the milk interact with sun to create a brief antiseptic effect. Any fungi present are "burned" into oblivion, but there is no residual effect after that. In order to be effective, milk sprays must be used preventively, must be applied in bright light, and should be repeated every 10 days or so." The dilution varies with studies. But there is another mold that may grow on the milk if it is more than 30%. Here is another article. Appalachian Feet. I MEANT to spray my peas before they got mildew, I need a calender to remind me of these things (a project for winter).