dear brains-trust

[tessa]

i have been battling this problem for a few years...and it's about to put me off of growing tomatoes altogether unless i can figure out how to win it.

every tomato plant i have grown, bar *one* (my much beloved, yet recently departed (RIP) tomatomachine that lived its entire life in isolation from other plants), has fallen victim to this problem.

in short...my tommies all start off fine...then two months in start to get a copperish sheen to the leaves, with purple veins on the undersides, and then slowly (but oh-so-surely) the leaves die, then go crispy...from the bottom up.

the other day i had a flash of brilliance (it's rare, ) and whilst googling this coppering effect...i decided to say 'rust' and then mispelled it (on purpose, of course) so that i got results for russet...which was a stroke of *genius*...because it led to a potential diagnosis...which is that i've got a bad case of 'tomato russet mites'.

with me so far?
so the next hurdle is that i'm trying to grow tomatoes organically...and i'm not having much luck finding solutions for my problem organically. i've started by spraying everyone down with pyrethum, garlic and chili spray.
do you think that will be enough?
is there anything else you think i should be trying?

also...the leaves that are not infested with mites, which are the sets of leaves just above the mites (you almost need a bleeding microscope to see these) are covered in these things:



what are they? they are half the size of the mites, and they look like sap droplets. could they be eggs? are the leaves leaking sap? what?
what should i do?????

that, btw, is a leaf from my 'happy f3'. she's still reasonably amiable....but happy might be stretching things a bit.

[mcsee]

You need to use a 'Sulphur' product or 'Wettable Sulphur' product to erradicate them, which may not fit into the Organic side of things.

Not sure what is available commercially.

[Suze]

Originally Posted by tessa

i have been battling this problem for a few years...and it's about to put me off of growing tomatoes altogether unless i can figure out how to win it.

every tomato plant i have grown, bar *one* (my much beloved, yet recently departed (RIP) tomatomachine that lived its entire life in isolation from other plants), has fallen victim to this problem.

in short...my tommies all start off fine...then two months in start to get a copperish sheen to the leaves, with purple veins on the undersides, and then slowly (but oh-so-surely) the leaves die, then go crispy...from the bottom up.

If it's spider mites, one thing I have found very helpful is a product called Pyganic (pyrethum). They used to just suck the life out of my plants when I lived a little further north in Texas, but since I've moved down in the state a little, I have not had problems with them so far.

So spraying like you did with pyrethrum should be helpful, but the garlic and chili wouldn't have any affect on them. Spraying is not a one time thing and will need to be repeated once a week, IME. Getting all surfaces of the plant is important, especially the undersides of leaves.

Also (you may already be aware of this), spraying with pyrethrum on a hot or sunny day can burn your plants, so keep that in mind when spraying. Spray in the early morning or late afternoon. Same cautions would apply with wettable sulphur which can also be helpful in treatment as mcsee mentioned, in addition to not using it at all if you've recently applied any oil based substances to the plants (like neem oil, etc).

Signs/symptoms of spider mites (russet mites are a type of spider mite) in order, include:

1) Dulling of the leaves. One of the very first signs of infestation, watch carefully for it early in the season. Don't wait for any further progression to start spraying, as it's harder to get them under control once the population multiplies.

2) Rasping of the leaves. Meaning little tiny yellow to white spots in areas where they have sucked juices out of the plant. Example, not a tomato leaf, though:

http://www.ent.iastate.edu/images/pl...itestipple.jpg

3) Russeting/crispy leaves, usually from the bottom up. By the time you see this on the lower leaves, the mites have already moved on up the plant and are well on their way to steps 1 and 2 above.

4) Dead plants. If left untreated. And of course, they will move to the next plants on down the line, if they aren't already there.

Another suggestion: Do a google images search on spider mites, and another one on spider mite eggs, so that you can compare the pictures with what you are seeing in your garden.

[Suze]

Another thing that I wanted to mention is that you might want to invest in a good quality hand lens (at least 10x power) if you don't already have one.

That way, you can see a little better what you have, and it is also helpful in monitoring the plants for initial infestation early on.

[tessa]

thanks mcsee and suze.
yes...i've got a hand lens, and so i can see them there now. they're still quite small to see even with the lens...but once i knew what i was looking for...they were easily spotted.

i've got big troubles because i have only a handful of plants that don't have these on them.

thanks for suggesting i google the eggs. i don't know why i didn't already do that....but i didn't.
i haven't gotten too far with it...but i came across this site that was really quite good. it's an african site...but they've got great pics and descriptions of pests and diseases.

http://www.infonet-biovision.org/default/ct/113/crops

back to googling.
i've *got* to beat this thing.
(neem oil will be my second line of attack)

[Suze]

Tessa, unfortunately, I haven't found that neem oil really helps much in getting rid of them. The regular pyrethum sprays have worked better for me than anything.

It also occurs to me to mention that in case you were considering trying the wettable sulfur at some point, I wouldn't use it if you are still using the pyrethum because it may have some oil component to it (at least the one I've used before does).

[tessa]

i'm still googling away.
i didn't realize that the wettable sulfur was considered organic. *duh*.
i'll check the pyrethum spray to see if it's got oil in it. i do see where it says that it can't be used on anything that's been sprayed with oil.
also the temps need to be under 90....which i think they will be, however, it doesn't say how long it needs to be under 90 *for*.
still working away at the problem.
i'll be just so happy if i can win this battle!

[Suze]

Something else I just remembered is that I've seen it mentioned several times that regular sprayings of seaweed emulsion can help in battling spider mites. I don't recall the specifics/science as to why, but it might be something else to look into in your google searches.

I somehow doubt it's as effective as pyrethrins are, but it couldn't hurt to try it in addition to (but not instead of) those other sprayings.

[mcsee]

Tessa - You will need to find if your pyrethum has added oil and is it washable so you can use other formulations that may go over it, or react. If washable, you could then use the wettable sulphur, if not you need to decide what is the next move.

If they were my tomato plants, I'd have sprayed them with Folimat and problem solved, but it depends on what road you want to take to eliminate the mites. (Folimat is oil based.)

[tessa]

well...i sprayed the pyrethrum about five hours ago.
just now...i went out with my hand held looker-er (magnifies by 8x) and i can't see a single mite!!!!
what the????
i reckoned that their dead bodies would at least still be there...but not!
all those glistening specs from the pic up above are still there...but not the mites.
*crossing my fingers*

[dice]

Here is something interesting to try (chitinase in
earthworm castings):

http://www.backyardaquaponics.com/fo...d46fb919c98040

I think there needs to be some bacteria around to exploit
the softening of the exoskeletons, but maybe that is always
in earthworm casting teas (and maybe molasses helps breed
more of them). The idea is that the bacteria get in through
the softening shell of the insects/mites and attack the organism.

You could drag one infested plant off by itself somewhere and
try it, in case results are unsatisfactory.

[Patrina_Pepperina]

Tessa, those glistening specs that look like tiny sap droplets are possibly glandular trichomes:

http://www.trichome.msu.edu/about/overview.html

http://www.ingentaconnect.com/conten...00006/00171622

http://www.blackwell-synergy.com/doi...8.2007.00625.x

Maybe the plant is putting out more resin to fight off the spider mites?

Patrina

[tessa]

oh THANKYOU! patrina.
i spent half of yesterday googling (unsuccessfully) for answers on those glistening thingies. it occured to me that they were too perfectly spaced to be eggs.
yes...so it seems the plant is trying to defend itself. amazing.
i am battling right alongside it.
now all we need are a few phasers and a photon torpedo.

[tessa]

well...i've just been out to the garden with my looker-er thingy...and i have great news to report!
i took the punt on the garlic/chili/pyrethrum spray that i usually use to kill the aphids with and it seems to have worked a trick! (i'm so relieved...because dice's excellent link and advice looked pretty labour intensive...and i'm lazy!).
when i spray the aphids with this stuff...it does a great job...but the aphid bodies still hang around and generally look bad. with the mites...i'm very suprised by this...they simply just disappear. there's not a living or dead mite body on the plants that i've sprayed.
i'll be checking daily for any emergence of baby mites...but with any luck, the eggs would have been sorted out at the same time.

here's a few pics that might help others to identify what's going on with their plants, should they have anything similar. i'm sorry to say that i didn't take any pics of the bronzing...but my surrogate veg patch is also infested and i'll try to get some good snaps of that when i go over there later today to spray down those plants.

here...without flash...you can see a bit of the bronzing on the stem, and the 'dirt' which i imagine to be poor housekeeping on the part of the mites.



do you folks think it's okay for me to go ahead and spray those fruit directly? i haven't done that as yet. too afraid.

here's a pic with the flash...which shows up pretty nicely all the glistening specs.



under the looker-er...those specs are all perfect little globes...uniformly spaced.

[Patrina_Pepperina]

VERY pretty pic of glistening trichomes Tessa!!! And I'm glad those spider mites ran away scared - must remember that brew. (What's it like for getting rid of Grubs? I'm finding green fruits fallen on the ground because grubs have eaten out the stem area, grrrrrrrr.... *sigh*)

PP