Is this little thing really what's destroyed my gardens?

[LDx4]

Naysen,

Thanks for the info on copper sprays. I followed your link to the UC IPM website and poked around a bit. I found this interesting graph that lists the resistance potential of various fungicides (see the last graph column). It looks like resistance potential is only medium or low at best for any of our proposed sprays: http://www.ipm.ucdavis.edu/PMG/r783900911.html

I'm going to take your advice though and spray tomorrow morning early with the Green Cure. Then I'll try the copper after the GC has had a chance to work (or not).

Steve, I'm pruning about half my plants to a single stem this year, and they're showing signs of this also, of course to a lesser degree with fewer leaves. This year just seems especially bad for L.T. to me. Since I'm fairly close to the coast (~8 miles, with marine air coming in through Mission Valley/San Diego River) I've gotten used to seeing it every May/June, but never to this degree. That may be why you're seeing it for the first time in your area.

I'll let you both know how the spraying goes.

Lyn

[Heritage]

Lyn, yes, maybe L.T. is just worse this year. What I was diagnosing as normal leaf senescence in past years may have been L.T. trying to gain a foot hold, but I ignored it. This year it is spreading, moving up the plant, and not so easily ignored.

Steve

[walkinggin]

I get this same condition every year and finally decided to call it powdery mildew last year. It took a while to convince myself because the powdery mildew we get on the grape vines looks completely different/more like the typical pictures of powdery mildew.

I have never had it kill a plant, though the defoliation used to really impact yield. The last few years have been much better and I think my early and regular applications of actinovate with a touch of molasses has kept it manageable. I do an application of greencure once I see the inevitable sign of it then subsequent alternating between the two treatments.

Naysen, you may want to consider that according to the greencure website:

Can I mix GreenCure with other products such as pesticides?
We DO NOT recommend mixing the product with other products because it could inadvertantly reduce the usefulness of GreenCure by altering its PH level.

I've even wondered if the high PH from my tap water might be a problem, but I've never taken the time to get an answer from the company.

ginny

[z_willus_d]

Hi Ginny, thanks for commenting. I was actually more concerned that the pH and whatever else of the greencure might kill off my Actinovate bacteria. But, I had also noted a comment somewhere in a study that the effectiveness of greencure could hing on pH. They didn't state what the target pH should be for optimal results unfortunately.

Have you ever used Sulfur to help with the PM? I was planning to alternate between Greencure, Actinovate+Excel-LG(Agrifos), and Sulfur applications. And for thrips, I would include Spinosad with the Greencure and perhaps an intervening pyrethren spray.

-naysen

[Paradajz]

Originally Posted by Heritage

Here's a couple of photos of what I've been calling Leveillula taurica, and some comments:

Photo 1 - two leaves from the same plant - the leaf on the left looks how I think of something systemic might possibly look - maybe V on this one, except the leaf on the right shows necrotic spots surrounded by yellow margins - maybe L.T. on this one.

Photo 2 - detail of the necrotic spots from the right leaf in photo 1.

Photo 3 - typical symptoms on two leafs from a PL plant. Again, I see possibilities of both L.T. and V.

I removed a lot of yellow leafs today - the leafs in the worst condition were, as Naysen also noted with his, inside the canopy where preventative sprays didn't reach and humidity is probably higher. This seems to indicate L.T. - I don't see how V. symptoms could be affected by canopy location.

Ivan, is L.T. identification something easily accomplished with a microscope and a few spare minutes in the evening, or would it require in-depth knowledge of fungi and more than a few hours of reading?

Thanks,
Steve

hi, Steve, good photos.

no V. there at first glance, and quite different from the situation with Naysen's plants actually.

a couple of questions:
* were the photos taken immediately after you picked those, or after some time?
* what was the position of the left branch from photo 1- low, midd, high?
* can you tell how the condition of the left branch photo 1 started, what were the first symptoms?
* did you by any chance cut that particular branch trough and examined the interior status?
* do you have any plants with equal symptoms on a single section of a plant ( just low, just right or left, just high )?
* are there any unusual stuff at low ( ground level ) steams of plants, and i mean not just discolorations, cankers, etc., but stuff like wrinkling, twisting, changes in diameter ?
* can you tell what were the initial symptoms of the right branch, photo 1 and 2?
* since you have mentioned that there is a history of this at your place, can you estimate the duration of the process- is this occurence something that appears and afterwards progresses constantly without a time limit, or you could call it timely limited in any range?

sorry for the interrogation, but Nyasen gave many more details in his descriptions, easier to go for an opinion there

anyway, at first glance left branch photo 1 appears systemic, far more like F. than V., but that condition could have been caused by zillion things- diseases, insects, nutrient disbalance, mechanics.
how often and in what range ( territorial range within your garden, and plant sections- inner/outer ) you meet that particular symptom and ( if you can tell ) does it tend to be terminal for the whole plant?

the right branch may also easily be F., L.T. with a slightly lower probability, bacteria not excluded, but it could actually suit plenty of other stuff- ranging up to even magnesium deficiency. how often does this appear, and does it follow/neighbours symptoms from the left branch?

just a few details:
* unfortunately you cannot distinct L.T. that easily, especially if you ''miss'' the initial symptoms visual appearance period. but, on the other hand, if you catch it on the very start it should be easy- in a simple language, the spot will appear on the front leaf side, at some 70% rate it will be close to white coloration, and in an extremely short time it will go to brown. it's only natural that this doesn't apply always and everywhere, but in an outbreak of a larger scale you should be able to notice this pattern.
* i feel that i am burdening people here with to many specific and complex subjects, but just this one more time: it's actually the NATURE of systemic poisoners like F. or V. and progressive/aggressive ''feeders'' like L.T. or A.S. that provides you with clues where to go.
systemic ones usually have the following pattern: it spends some time at parenhim ( don't know the term for this in English, sorry ) tissue of the roots until they enter xylem, spend quite some time there until the number of it saturate enough to move upwards ( and both F. and V. move upwards although a theory that V. rarely does was long loudly spread ), and eventually some of it ends up ''working'' within leaf surface. out of this comes the main characteristic of it's possible leaf appearance: coming from the ''pipes'' it will always do it's work between the veins, which ends up as a visual appearance of green/ish veins and yellow/brownish chlorosis/necrosis areas between the veins. very often this will be a crucial clue where to go with the diagnosis, since ''feeders'' don't mind eating veins also which often provides us with a needed distinction.
of course, this won't be always like that, or at least not that easy, but the final outcome with such diseases visual appearance really depends on such a number of variable factors that i would earn a pension writing on this thread

anyway, if i was to take a really long shot with solely photos you provided and without thorough description(s), i'd go for a touch of F. at high- strength plants with you, with some possibility of L.T. as a secondary disease added to the drama.
details like your plant's sorts, resistance, feeding, watering, weather conditions, strength estimation, etc. would also help

as for interior- emerging leaf symptoms which you reason as a clue in favor of L.T., it actually depends on temperatures- it's actually the only natural place for V. to appear at high temps ( above 25C ) and it will only go to outward sections if a plant is weak and the disease manages to progress to a terminal stage.

but, since i noticed that huge number of people have a similar L.T./something else dilemma, i would recommend that, in case that substances such like difenoconazole or penconazole are available to you, simply pick a plant and spray it with it as a test- in less than a day it would stop L.T. as a hammer.

br,
ivan

[LDx4]

Well, I spent a number of hours today pruning diseased leaves from 150+ plants and I might have two different strains of powdery mildew going on. Unfortunately, I didn't think to take any photos while I was out there pruning leaves, but I found this website from the Arizona agriculture dept that shows my plants exactly.

http://ag.arizona.edu/plp/plpext/dis.../tomato/pm.htm

So now I think I've got both Leveillula taurica (Oidiopsis sicula) and Erysiphe (Oidium lycopersicum) at play. Picture #1 on the AZ ag webpage looks just like my Leveillula taurica infection and picture #5 is just like my Erysiphe infected plants.

Paradajz (or anyone else), it's my understanding that V. lives in the soil and is transmitted primarily through the soil? I ask because I do all my growing in containers using soil-less potting mix, so I was under the impression that I had a low risk for V. infection.

Ginny, thanks for sharing on your experiences and the Greencure usefulness. I'm going to spray tomorrow and start a regular spray program with it.

Thanks everyone for your input!

Lyn

[z_willus_d]

Hi all. Ivan, again, thanks for taking the time to post with all the detail. As I've said before, I'm still not convinced of V for any of our cases, but I can't deny that the wealth of knowledge and details you're dumping on us is great to have here. I would love for tomatoville to foster a discussion board for the dissemination for research and other pedagogical outputs.

This evening, I sprayed the patio/container plants, which include peppers and eggplant, as well as my 2nd raised-bed tomato bed, which includes also tomatillo, spaghetti squash, melon, and zucchini plants. I sprayed with the greencure potassium bicarbonate product (4 gal total), but this time ommitted the Actinovate bacteria, Spinosad, and Mycotrol O for fear I might change the pH of the fungicide and affect its efficacy. It calls for 1-2TBS per gal, and I used 1.5TBS or 6 total for my tank. I quickly used up my 8-ounce container of the greencure, but I think I'll be switching to sulfur here in about a week (as soon as it arrives in the mail).

As for the plants I sprayed yesterday, well I can't say I see more yellow, but what I do see is a lot of brown and black and death. The leaves yellow leaves have crisped up. A large portion of the green leaves near the yellow leaves have also taken on a deathly pall. I thought it was curious (a good or bad sign I do not know) that the Brandywine Sudduths that had droopy yellow/brown leaves (see attached pic) was today no longer soggy/droopy but rather "crispy" on those same leaves.

I'm not expert enough to say yet whether I'm on the right track or whether these plants are going to pull through. Tomorrow, I'll try and take more pictures of the survivors that will be one or two days after the greencure treatment.

Good luck all.
-naysen

[Heritage]

Ivan, I appreciate the detailed evaluation and invaluable information! I've learned a ton about L.T. and V. the last few days., thanks.

I keep hoping you are missing something in your diagnosis of Naysen's plants - however, you seem to have a well-rounded familiarity with tomato diseases, a wisdom born of experience, and not by Googling, so my hope is not great. Your explanation of V. occuring inside a canopy satisfies the last argument I can think of against a V. infection. Still, it doesn't feel quite right...

As for my situation, I'll try to get a time-lapse photo of a leaf going through it's changes and will post when the sequence is finished. I don't feel my problem is critical, nothing has progressed beyond the bottom third of the canopy. The heat and humidity was lower today and I don't see any new yellowing since yesterday.

btw... you mentioned difenoconazole as a knockout for L.T. and I read it is a Triazole fungicide. Do you know if mycobutanil would also be effective against L.T.? Thanks.

Steve

[z_willus_d]

Steve, UCD listed it as the 2nd most effective treatment for tomatoes for our presumed L.T. PM strain. You've probably already seen this, but just in case.
-naysen

http://www.ipm.ucdavis.edu/PMG/r783100411.html

MYCLOBUTANIL (Rally) 40 WSP 2.5–4 oz 24 0 MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)

[Heritage]

Thanks Naysen, I missed seeing that.

[Paradajz]

Originally Posted by Heritage

Ivan, I appreciate the detailed evaluation and invaluable information! I've learned a ton about L.T. and V. the last few days., thanks.

I keep hoping you are missing something in your diagnosis of Naysen's plants - however, you seem to have a well-rounded familiarity with tomato diseases, a wisdom born of experience, and not by Googling, so my hope is not great. Your explanation of V. occuring inside a canopy satisfies the last argument I can think of against a V. infection. Still, it doesn't feel quite right...

As for my situation, I'll try to get a time-lapse photo of a leaf going through it's changes and will post when the sequence is finished. I don't feel my problem is critical, nothing has progressed beyond the bottom third of the canopy. The heat and humidity was lower today and I don't see any new yellowing since yesterday.

btw... you mentioned difenoconazole as a knockout for L.T. and I read it is a Triazole fungicide. Do you know if mycobutanil would also be effective against L.T.? Thanks.

Steve

hi, Steve.

no real wisdom there, just a certain amount of understanding.

i have been mentioning Triazole fungicides for P.M. at a couple of other threads here, mostly because of it's widelly proven effects and generally low level toxicity of the group.
yes, the product you asked about should do- if it doesn't totally knock it out it will show an absolutely visible setback, sufficient for a positive conclusion. so, if you do it, just find plants with sufficiently vissible agressive symptoms but also in as early stage of disease progress as possible, and monitor carefully, 24-96h period after the spray especially ( the first appearance of the set back ), and pay attention to the fact that Triazoles will upper their effect from day to day with a maximum point in 12-14 days after the spray.

br,
ivan

[walkinggin]

Naysen, I've never tried the sulfur, where did you order yours from.

About the condition of your leaves, might not that be the result of your spraying hastening the death of the leaves, with any of the leaves which were affected by the PM looking worse, similar to how spraying with bleach affects the plants?

At least thats what I have always thought. In any case I do find that to sometimes be the result of using greencure. Which I think is ok, I'm not interested in the sick leaves, I'm trying to control the spread to the healthy leaves. Thats why I generally spray with actinovate/molasses only a day or two after the greencure spray, to give some protection back to the remaining green leaves.

ginny

[z_willus_d]

Ivan, just out of curiosity, can you provide a pointer to a commercial fungicide product that uses Triazole as it's active ingredient? I didn't see anything listed under the UC Davis site (link posted above), unless TRIFLOXYSTROBIN is a triazole.

Ginny, I went with the lifetime 30lb supply from Keystone Pest Solutions (online store):
"Kumulus DF Fungicide - 30 LB (Cert Organic Sulfur),"
http://www.keystonepestsolutions.com...FWKCQgodYgQAXw

Yeah, I hear that a lot about how the infected leaves (even those that appear ok when spraying) once sprayed will die and crisp up. Bill has stated that about the bleach solution, and I believe I've heard it stated in association with other fungicide applications. I know that all of these infected leaves are going to die sooner or later. I've never read an official explanation or forewarning that states that an infected leaf, however imperceptibly on day of spraying, will dry up and die the day after spraying of a fungicide. I realize that seems to be the common knowledge, but I'm surprised they don't label a warning about that on the fungicide packages. It actually would be a nice sign that the stuff is working. On the other hand, I've wondered also if it's a sign that the fungicide is somewhat caustic and can damage healthy and unhealthy leaf growth alike. Maybe, the older the leaves, the more likely it dries up and dies. I just don't know for certain which is true.

-n

[Paradajz]

Originally Posted by z_willus_d

Ivan, just out of curiosity, can you provide a pointer to a commercial fungicide product that uses Triazole as it's active ingredient? I didn't see anything listed under the UC Davis site (link posted above), unless TRIFLOXYSTROBIN is a triazole.

-n

hi, N.

no, only myclobutanil is a Triazol there, trifloxystrobin, pyraclostrobin and azoxystrobin are all Strobilurins ( synthetic, but with a fungal ancestry actually ).

if you still chose to test some of those aiming for L.T. my advice is to use myclobutanil, Triazoles are not very likely to cause any resistance that soon.

Strobilurins on the other side are excellent fungicides, not agressive and mainly traveling trough leafs only ( local- systemic is the term in my language ), with extremely broad spectrum ( practically all 4 existing groups of pathogenic fungi ), but with a somewhat less effective action than Triazoles, and highly problematical on the resistance side. therefore, if you use those mix it with mankozeb/propineb at regular doses. my advice there is pyraclostrobin as first choice, although trifloxystrobin has some nice additional effects on a plant ( helps photosynthesis ).
anyway, this group shouldn't be used more than once for P.M. with a strong recommendation for a combination with some broad contact fungicide, and even stronger recommendation of using a fungicide of completely different system of action if there happens to be another treatment for P.M.

br,
ivan

[Paradajz]

Originally Posted by LDx4

...
Paradajz (or anyone else), it's my understanding that V. lives in the soil and is transmitted primarily through the soil? I ask because I do all my growing in containers using soil-less potting mix, so I was under the impression that I had a low risk for V. infection.
...

Lyn

Lyn,

you do have a low risk of a V. infection.

as i mentioned before, some strains prefer developing mycosclerotia in weeds for example, than again some will end up doing their job in leaf area ( and produce conidia there ), and those are always a significant risk of splash back infections, because these villains are absolutely able to find their way into a plant trough any open wound that might be there.
eventually, growing in containers, sterilizing hands and equipment and weed control make it a really minimal risk to you, if seeds/seedlings aren't contaminated of course .

br,
ivan