Fava Bean Rust

This is a plant with a severe case of fava bean rust, or Uromyces viciae-fabae.

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No, the plant is not oxidizing. Rusts are plant diseases that give the impression of rusty spots, but really those are pustules (great word eh?) containing fungal spores. Most of the fungus consists of threads called hypae that are all tangled through the plants, robbing them of nutrients in plant sap. The spores released at the surface are ready to float away and find a new plant to infect. Here are some close up shots of the spore pustules:

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I see the disease fairly often in San Francisco gardens. It does probably reduce production somewhat, but it often occurs later in the season, after most of the crop has formed. Here are some ways to lessen your chance that it will occur or reoccur:

--This disease is encouraged by wet leaves, so try to water favas at the ground level, rather than sprinkling them. Of course we can't prevent rain and misty weather, but the less dampness the better.

--If you see the disease early, with only a bit of damage, you might slow it by removing diseased leave, though of course you don't want to take too many leaves off of the plant.

--If your plants are ripening beans, you will be reluctant to take them out until you harvest, but as soon as you can do so, take th plants out. Do not compost them. In San Francisco, you can put them into a green bin for Recology to compost, since their compost gets very hot and should kill the spores. When you take your plants out, pick up all the fallen and dried leaf debris you can find as well.

--Don't save and replant seed that came from infected fava bean plants.

--Copper sprays, which are approved for organic farmers, may offer some control. However, they will be a lot of trouble for a small planting, and will harm the soil if used repeatedly.

--A two to three year rotation might help, but if your garden is open to breezes from nearby plantings, the spores may be reintroduced.

(See also on this blog posts on chocolate spot disease and the black aphid that infests fava beans.)


Disease of Fava Beans--Be Very Afraid

Recently I saw a disease on fava beans that was unfamiliar to me. It wasn't rust, which makes rusty brownish pustules on leaf undersides. No, these were nasty brown spots on the leaves that merged, became almost black, and destroyed the leaves. My diagnosis is chocolate spot disease, which is caused by the fungus Botrytis fabae.

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Here is an early stage. Then the spots merge and darken. The leaf below is on its way out.

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Notice the tear in the middle of the leaf, caused by dead tissue.

I don't have a description of this disease in any book, though one, The Self-Sufficient Gardener, by John Seymour, mentions that "horse beans", the smaller favas farmers feed to livestock, are more susceptible to it than the larger ones humans usually eat. This book is an English publication, and favas are an Old World native bean, so it is probable that they have had some fava diseases longer than we have.

Be that as it may, when I read the Wikipedia article here, I realized this disease could spread fast once it appears. The spores can be carried on or in the seed and can also form resting bodies that lay in wait in the soil until you plant the next fava bean crop. It can also survive "in crop stubble and residue." (That's the cut stems and all the fallen leaf debris you forget to gather up when you take out the diseased plants.)

When the spores germinate, the lesions begin to appear, and within 4-5 days, new spores are released to infect new leaves, stems, or flowers. These spores blow in the wind to new plants or in splashing water. The spores and disease are most active in cool, humid conditions, which is what we've got much of the time here in SF.

So if you have seen this disease on your fava bean plants, take those plants out as soon as you can. Take the whole plant out, roots, fallen leaves, everything. Do not compost it in your garden, though the SF Green Bin is generally OK for diseased plants, since their process is very hot and thorough. Do not save seed from these plants. It should be OK to eat the beans that aren't disfigured by any lesions. This fall, try to avoid planting favas in the same place you used last year if they were infected. Get fresh seed, and look for varieties that have shown resistance. (I will look for some--no idea where to find 'em yet. Send a comment in if you find some, please.)

Another web page says that this disease was first documented in California in 1998. It was found near the coast, no surprise, considering its adaptation to cool, damp weather.

I suppose that farmers who aren't farming organically use fungicides that organic farmers wouldn't use. What would I use? I notice that the label of Serenade fungicide includes both "vegetables" and the plant disease genus "botrytis," so I think I'd give it a try.

Serenade, which is permitted to organic farmers, has as its active ingredient the common soil bacterium Bacillus subtilis. This organism colonizes the plant surface, I've been told, preventing other microorganismns from getting a spore-hold. You spray it on plants weekly. They recommend spraying on a small part of the plant first to see if it will harm the plant. You can apply it up to the day of harvest. (This is not a recommendation, just my thoughts on what I might try and why. As with any pesticide, read the label for yourself before you buy, mix or use it and follow the directions carefully)

However, as with any plant pest, it would be quite unwise to try to control it using a chemical. If you have seen this disease, I repeat: Get those plants out of your garden. Rotate to a new site for favas. Don't save seed. Help me locate some resistant varieties. Then, if you had this disease this year, and have planted fresh seed in a new garden location, next fall, you might try spraying the plants when they are young, before any disease has appeared, to try to prevent an outbreak.

By the way, our favas have not had this disease, I am happy to report, and we've been eating young fava bean pods, when the seeds are still small, roasted in the oven according to a recipe that appeared in the SF Chronicle a few weeks ago. You roll them in olive oil, add salt and pepper, and roast at 450 degrees for about 25 minutes. Sprinkle with more salt, eat pods and all. Serve as a side dish or just before a meal. You may have to pull strings off the pods, but they sure are good!


Tomato Trials 2011

That mean old late blight strikes every year in my community garden and when I am foolish enough to think I can grow tomatoes at City College, so I am still on the lookout for a late blight resistant variety or two. Inland gardeners may escape this nasty disease, but it is thriving in cooler gardens near the coast.

Two years ago, in a trial reported in this blog, I grew several varieties that "someone" on the web said resisted late blight where they garden. Not a very scientific choice, but for several years, I tried the ones that wholesale seed companies and universities have been developing for resistance and none of those worked, so I was ready to try anything.

As a review, tomato late blight, which is the same as potato late blight, and which caused the Irish potato famine, is not soil borne, but carried by aerial spores from infected plants. It appears rather late (as in late blight) in the season. There are dark brown lesions on stems and leaves, followed by general collapse of the plants.Here are a couple of photos of plants with symptoms:

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The fruit may start to show the greasy brown coloration near the stem while it is stil green, or after it ripens. This may spread to whole fruits. In any case, fruit on infected plants ripens poorly and isn't sweet.
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The one variety that has been on the market for several years is 'Legend'. In my trials, it was the first to die. Here is the miserable dead plant of 'Legend' in 2009:

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Of the others I tried in 2009, my best plants were 'Juliet', which now is sold with a notation that it has some resistance to "Blight." (Not very informative, since there is also an early blight, a disease much more common in the Eastern US, but an entirely different disease.) Here is 'Juliet' in 2009:

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Although 'Juliet' had a touch of late blight, it produced a huge crop of these plum-type fruits--bigger than a cherry tomato, but smaller than a standard paste tomato. They were, however, perfect for the Broiled Tomatoes with Herbs and Cheese recipe I printed in Golden Gate Gardening.

In the past couple of years, late blight has been appearing on the East Coast as well as in the West. A few more supposedly resistant varieties have appeared, and I am trying 4 new ones:

Plum Regal F1 (Salsa/Sauce/Drying) 68 days

Golden Sweet F1 (Yellow Grape) 60 days

Mountain Magic F1 (Red, tall vine) 70 days

Defiant PHR F1 (Red, short vine) 70 days

So, I got them all from Johnny's Seeds, who may or may not have seeds of them left this year. They are all hybrids, and all relatively early. (The number of days doesn't count the 6 weeks or so to grow transplants, but anything under 75 is reasonably early.) The one I am most hopeful for is 'Defiant', since it has a formal "PHR" after the name, stands for "Phytopthora Resistant". (Phytopthora is the scientific genus name of the late blight fungus.) 'Defiant' is also said to resist 2 strains of the disease, so maybe it resists the strain we have while others didn't?

The plants will be potted up this week, planted out in May in one or possibly several San Francisco test sites. Stay tuned!

 


Another Year in the Life of An Apple Tree

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Our apples at their best.

In the ongoing saga of our apple tree, a tree of unknown variety but good fruit and usually good production, another harvest is past. This year we finally got rid of the woolly apple aphids, after two years of spraying the insects with rubbing alcohol (right out of the bottle) weekly and 2 commercial canola oil sprays each winter on the dormant branches. Because the insects spend part of their time in the soil, we also used the canola oil pesticide as a soil drench twice each winter, watering before and after we sprinkled it on the soil surface (an off-label use the idea for which  I got from reading research reports about the pest in the East ).

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Woolly apple aphids make huge galls where they suck sap from the branches, as they have done here on this pruning cut (not on our tree, thank goodness!). They are reddish aphids, but are covered with a white waxy fluff.

 We also think it helped that we discovered the trunk had been buried a foot or so deep yea all these years, since before we bought the house, and unburied it. A buried lower trunk is really bad news for any tree.

But because we were paying so much attention to the woolly apple aphids, we forgot to spray sulfur to prevent scab, the disease that makes surface blemishes on the apples. We were also lulled by the dry early spring into thinking that scab wouldn’t be a problem this year. The early-setting fruit did fine—no scab. Then the spring turned wet, and the later-setting fruit was attacked by scab. (Our tree is borderline for getting enough winter chill, so sometimes it blooms over a long period.) Some of the later forming fruit was so affected that it was stunted and malformed.

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Some of our apples with scab disease. Note damage to leaves from the disease as well.

However, overall the tree became so vigorous (when liberated from the extra foot of soil and freed of the stem and root sucking of the woolly apple aphids) that we wanted to be sure to give it a summer pruning to curb its excess growth. But the summer was so cold and foggy that the tree seemed always to be wet. So we put it off, hoping for a dry day. That day came, Lisa pruned the tree, and boom, we had a heat spell. So some of the apples developed sunburn on their southeast sides—big round black sunken blotches.

 Then came October 15th, the usual ripening date, but most of the fruit was clearly not ripe. it was still green under the red streaks, very hard, and had its flat, starchy, unripe flavor. Now, in mid-November, it is finally getting ripe. Many of the fruits do have some scab, and a few (not as many as it once seemed) have the sunburn, which will prevent them from keeping well. But overall, there is more than we can eat, as usual, so it’s off to the Free Farm Stand (after our friends and neighbors have been given as many as they can use). And off to bake pies. I photographed the making of an apple pie and plan to put the photos, with recipe, on this blog in a day or two.

 


Syrphid fly in my backyard garden

Last week I was out early in the morning when a spiderweb hanging between a chair and a columbine was still decorated with crystalline dewdrops, each one a rainbow. I was checking what was coming into bloom, when I noticed a handsome sryphid fly on a potato plant. It was still sluggish from the slight morning chill, so I thought maybe I could get a photo. I ran up to bring down my camera with a close up lens, and lo, it was still there. So here is the my best shot.

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I am always glad to see a syrphid fly, because their larvae eat aphids and other soft-bodied insects. This particular syrphid fly is a bit smaller than a honeybee. It looks kind of like one, but those markings are just to fool a predator. You will see syrphid flies hovering around plants, like little helicopters. Because of the way they fly, they are sometimes called hover flies, and because they hover around flowers, they are also sometimes called flower flies. They may be striped or may be single-colored, and may be much smaller than this one, but by their hovering shall you know them.

Look closely at the insect, and you will see that it has only 2 wings. That is characteristic of flies, which are in the insect order Diptera (di=2). Most insects have wings, and all the other ones have 4. 

A couple of weeks ago I gave a talk at a garden club in the East Bay. It was outdoors, in a garden, so instead of bringing a show of photos, I brought some vegetables and vases of flowers, some edible, others to attract beneficial insects. As I was talking, a syrphid fly came along and checked out the flowers. It considered seriously the collard flowers in the bouquet of edible flowers, but rejected them and settled on the parsley flowers in the vase of flowers to attract benificials. Point well made.  


Tomato Trial Results

This is 'Juliet' the winner in production and tomato late blight disease resistance in last summer's tomato trials. Of all the varieties I grew, it had the best production and withstood the blight the longest. It is a hybrid, and indeterminate (tall) plant. Juliet green 08 copy It was advertised as "grape" type, but the fruit was much larger than a grape, as you can see in the photo below, often reaching 2" long. It was just right for quartering lengthwise and adding to a salad or for halving lengthwise

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to stuff and broil as an appetizer. Not a really great flavor or texture, but OK and far better to have lots of OK fruit than 3 or 4 really good ones followed by death of the plant, as happened in the following case. 'Green Zebra' is an heirloom with fruit that is green when ripe, with yellow strips. This is how the plant looked by the time the 'Juliet' was in full production:

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This 'Green Zebra' grew to about a foot and a half, bore 4 ripe fruits, then died, while the 'Juliet' reached 3 1/2 feet with probably a couple hundred fruits. The photo below is of 'Legend', the variety bred to resist tomato late blight at Oregon State. It was actually the first to die. So much for the theory it was resistant!

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I think we have a strain of the fungus that it can't combat.

So what of the others I planted? 'White Currant' bore second most fruits, though they are very small, and had somewhat more blight damage than 'Juliet'. It is another indeterminate plant. It is very rangy, reaching its branches out far from the support. The fruit has a somewhat different, intense flavor, that some liked, and others found too surprising. There are also red and yellow versions of currant tomatoes, but I happened to get the white (which is really pale yellow). All are supposed to show some blight resistance. I thought they would be tiny, but many were the size of smallish cherry tomatoes. They were nice in salads.

The point of my trial was to grow varieties that anyone, someone on the net, a seed company, another gardener, claimed to have resisted blight. Another of these was 'Koralik' a determinate cherry-type tomato, an heirloom from Russia, that Territorial Seeds said seemed to have some resistance and to be early and productive for its size. These plants had more damage than 'Juliet' but did do relatively well.

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They were a standard cherry size and flavor. Nice, though not remarkable.

Another, 'Tommy Toe' showed similar resistance. It is a taller plant, but not as productive. The fruits are round, and a bit larger than most cherries. They were as wide as the fruit of 'Juliet', but round rather than elongated.

'Matt's Wild Cherry' was the last of the tested varieties. It did have a crop, not much bigger fruits than the currant tomatoes, not as strong a flavor, some blight damage.

All of the above was at Dearborn Garden in the Mission, which is relatively sunny. The following images are from City College of San Francisco, where I had a second planting. Here it is colder and damper, so when blight is present, it does more damage. I did get some good ripe fruit from all trial varieties except Legend, but by the end of the season, all were suffering.

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I think this is 'Tommy Toe', with typical brown fruit and brown stems caused by blight.

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Here is 'Juliet'. The fruit toward the back has typical browning, and you can see that the stem to the left is still green, but the one it joins is brown and so are the leaves.

 So what to do next year? Any other tips out there? Are there any other varieties you've found to have a vestige of resistance? Otherwise, I guess at least I'll have some tomatoes next year from 'Juliet' and one of the currant types.

All you tomato gardeners, if you had any blight this year, and your plants are still in the ground, get out there and rip them out. Pick up every fallen leaf. Do not compost the dead plants. Don't replant until April. This gets rid of last year's spores. More may blow in. The disease is airborne, not soil borne, but at least you aren't harboring it over winter. Take out peppers and eggplants and any leftover potato shoots too.

Finally, I will share a sign I saw in my communty garden. The gardener said he'd been in a demo and happened to have it along, so he thought he'd display it:

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Tomato Late Blight Report

In March, I got seed for a number of tomato varieties that someone or other said might resist tomato late blight, the awful disease, spread by airborne spores, that has been killing a lot of tomatoes in the California Bay Area for about 15 years. (and has recently been killing East Coast tomatoes as well) I planted some of them at City College, and some in my Mission District community garden. I also planted 'Stupice' tomato as a control--a plant I know gets late blight, just to be sure it's around.

The plants are bigger at City College, probably because the soil is in better shape. There are only a few blight lesions here and there on the plants. They ripened a few fruits in July, but a long foggy period in mid July through early August has meant a break in ripe fruit for now.

At Dearborn, more fruit is ripening, due to the warmer microclimate. I have lost one plant to late blight, and it is a 'Legend' tomato. This variety was bred to be late blight resistant, but clearly can't resist the strain, or the plant pathologists call it, the race, of late blight we have here. The plant is now only a couple of brown stalks. Some of the other plants have some blight lesions on stems or leaf stems, but are still bearing. The best looking plant, good color, lots of fruits, and no sign of late blight so far is one called 'Juliet'. If this one proves resistant, I will be realy pleased, because it makes nice oval fruits, like paste tomatoes but smaller, and lots of them. They are bigger than a cherry tomato though, about 1 3/4 to 2 inches long. Flavor--not too great, but they worked really well to make broiled appetizer tomatoes last night.

(Recipe: Mix 4 tablespoons of finely chopped green onions, 4 tablespoons of grated parmesan cheese, 4 tablespoons of mayonnaise, and two tablespoons of finely chopped Italian flat-leaf parsley. Cut 6-8 small tomatoes in half. Spread/mound the cheese mixture on the halves. Broil 2-3 minutes or untill the high places on the topping just begin to brown. Serve hot as appetizer or side dish. This recipe is in my book Golden Gate Gardening.)

Anyway, I promise photos soon. And welcome any reports or photos from others who may be growing any of the varieties we grew at City College last spring.


Plum Problem--Scars on Fruit

PlumProblem72 copy Here is the photo that went with my SF Chronicle (and sfgate.com) column last Sunday. I'll bet it looks fine on the website, but in the paper it was in B&W and was printed so low contrast that you couldn't really see the damage on the plums. So for those who couldn't make it out, here it is. Those scars were caused by a leafroller, a caterpillar that is the larva of a moth.

     What was interesting to me is that when you see photos of the damage this caterpilar causes, you always see either the caterpilar or the damage it does to leaves, rather than fruit damage. It is the sleuth symptom, never considered important enough to show, so always a mystery to most of us.  

     I have seen damage like this for a long time, on various fruits, and nary a photo anywhere that was captioned to explain what did it. My dad called them "bee stings", though we both knew that wasn't right. Thank you to Anita Crotty, who took this photo and asked what caused the damage. And thank you to Dr. Paul Vossen, who filled me in on the cause of the scars.

     Apparently the caterpillar feeds on young leaves, making a bit of webbing to roll a leaf around it to hide from predators. If the leaf is next to some very young fruit, the caterpillar nibbles a bit of that too. If ignored, the problem can get worse every year. If you see these scars one year, you can prevent the insect from overwintering on your tree by using a dormant oil spray in January or February, before the buds begin to open, or, failing that, using some Bt spray when you see tiny caterpillars, about when the tree is in flower.

     


Tomatoes Planted for Late Blight Trial

Today I finally planted the last of the tomatoes for the tomato late blight resistance trial. I have some at City College and some in my community garden. Three other people I know of are planting them together as a trial, one in Berkeley, one east of the hills in the East Bay, and one in Moss Beach. I'm wondering if anyone else who purchased the plants at the City College plant sale has logged onto this blog to read about the trial. If you did, please send a comment, so I know you are out there.

Now there is nothing to do but wait. Late blight is, as the name shows, usually late. That is, it will show up after the fruit has set and is ripening. To succeed in this trial, all the plant has to do is stay healthy. I will be taking pictures as the summer progresses.

For more on late blight, do a search in this blog. Try "tomato disease" for a link to some very good photos of the disease.


Lost Garlic Crop



2009 February-March 043 copyThis is the photo I ran a couple of months ago of the wonderful garlic crop developing in the City College garden. I was looking forward to teaching about garlic next fall from the harvested bulbs. But alas, we had a late rain and the whole planting collapsed.
The cause., as far as I can tell, is garlic white rot. I realized I have been putting off reporting this sad 2009 Early May 021 copy
news, but I did take the photos, so better get it over with.

This is how the plants looked last week. Just about dead. It isn't the normal drying off that the healthy plants begin about now and finish by the end of June. The plants just collapsed in a couple of days. Generally, the infection arrives on the sets, the little bulbs you plant. I got these at the nursery, which is about all you can do to try to avoid the disease. The rain caused the fungus to grow, but it had to have been there already.
So what does the UC IPM site suggest? ( www.ipm.ucdavis.edu and follow the links to garlic and white rot). They say the fungus can live in the soil for 20 years. Great!
To prevent it, one can try dipping the cloves in water that is 115 degrees, but you have to be careful, since 120 degrees can kill them. This would be one of those operations you carry out witha little bowl, an immersable thermometer, maybe a meat thermometer, and pitchers of hot and cold water.

2009 Early May 020 copy The other suggestion for organic gardeners, is to purchase a garlic extract product that you can apply before you plant garlic again. The fungus doesn't make spores, but tiny bits of itself harden into black dots the size of poppy seeds. If you wait a year after the infection, then treat the soil with the garlic extract, it can trick the black dots into growing, then, because there is no garlic to live on, the fungus will die.

That's a bit of a wait, but I don't see another solution on the horizon. Here is a pulled bulb of sick garlic. Not clear and clean as it should be, but covered with clinging soil, even though the soil wasn't overly wet, and you can see some of the white fungal growth.

I guess the only good news is that the disease is only of the garlic. The lettuce and arugula can't get it, or can the trial tomatoes (that are being tested for late blight resistance). And I can't catch garlic white rot.