Can anyone identify this leaf problem?

[jhouse]

I found one more leaf affected today, half way down the plant in the middle, all the rest looks fine.
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[Dutch]

Grey mold can be a problem here in Wisconsin. The gray mold problem usually develops up here after a wet period and can be quite bad in late summer after a Panhandle hook tracking storm. I use Actinovate to combat my mildew and mold problems.
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Dutch

[StrongPlant]

I didn't want to open a whole new thread,I just need someone to identify these 2 diseases.I am pretty sure they are both fungal.The first one looks like spots on the leaf that are brown-ish and powdery on the underside:



The second one is much worse.The stem initially turns brown,then it creeps upward,affecting the blossoms and leaves,which after turning brown quickly dry up.There is also a powdery feel on fingers after touching infected plants:





Intrestingly,those 2 diseases affect the plants in the greenhouse much worse then those outside.The greenhouse is very well ventilated and plants are kept dry,watered by a drip system.The second disease eventually overwhelms the plant and kills it.The fruit is unaffected by the second one if it is big enough,but doesn't reach it's full size because there are no leaves left to feed them...blossoms on the other hand dry up just like leaves.
Please if anyone can ID them I would be grateful,but I need the actual latin names of the organisms causing this.

[gorbelly]

StrongPlant, my guess for the spot problem is powdery mildew. It's a mildew that does better in hot, dry conditions, actually, as water washes it off the plant. There are many treatments that address powdery mildew. There are different organisms which cause powdery mildew, so I can't give a definite scientific name.

The second problem is a bit harder to diagnose. My first impulse would be to look for russet mites, Aculops lycopersici, another problem that prefers hot, dry conditions. They are really, really tiny. You'll need a magnifying glass to see them.

[cassiani]

just went to the garden to plant new basil. I noticed and removed a dozen of sick old bottom leaf on my brandywines. Should this be consider normal or serious? Next to them i grow 8 hybrids witch are ok and 5 sweet-100 and one is affected.

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By the way I have 9 brandywine in that patch 2 of them are already 6.5 feet with a lot of fruits!!

any help is appreciated! Thanx!!

[StrongPlant]

Originally Posted by gorbelly

StrongPlant, my guess for the spot problem is powdery mildew. It's a mildew that does better in hot, dry conditions, actually, as water washes it off the plant. There are many treatments that address powdery mildew. There are different organisms which cause powdery mildew, so I can't give a definite scientific name.

The second problem is a bit harder to diagnose. My first impulse would be to look for russet mites, Aculops lycopersici, another problem that prefers hot, dry conditions. They are really, really tiny. You'll need a magnifying glass to see them.

omg!!! You are right! It is the mites,I just looked at the sample from my greenhouse under microscope! The brown stuff that I see is actually their poop,that's so gross.If only I found out earlier,they have already caused heavy damage.And if only I sprayed them with water occasionally this probably wouldn't happen.Plants that are outside are barely affected because of the heavy rains we had.Well,time to grab that hose and wash 'em away
gorbelly,you have helped me more than you think,I misidentified the "disease" as some kind of blight wilt,and since I'm doing breeding work and selecting only the healthiest plants I would have copletely discarded the infected varieties as useless to me and would have never planted them again.You have my eternal gratitude

[StrongPlant]

Oh no,I was just reading about this mite and it seems the hot temperature and high humidity are what's aiding this mite's progression...so I guess the water treatment won't help.I also read that it can't survive freezing temperatures so I will try to leave the greenhouse open during winter so the soil can deep-freeze.I will let you know if I find a way to get rid of them without the use of pesticides.Oh and if someone knows a way already please let me know.I am thinking about gassing the greenhouse with CO2 or wood smoke...

[Dewayne mater]

Jhouse - that still looks like grey mold to me. If so, I'd consider use of Bill's diluted bleach spray. In my experience, it is always far more advanced that meets the eye. It is a quick killer that needs to be addressed radically and as quickly as possible.

[gorbelly]

Originally Posted by cassiani

just went to the garden to plant new basil. I noticed and removed a dozen of sick old bottom leaf on my brandywines. Should this be consider normal or serious?

Looks like septoria. Could also be bacterial speck or bacterial spot, or a somewhat atypical appearance of early blight. The action needed is the same: remove affected leaves ASAP and apply fungicide that will treat these diseases to all your tomato plants. You may not achieve a "cure", but you will definitely slow down disease progress on already affected plants, and you may prevent other plants from becoming infected. If you search on the forum, you will see many recommendations for other fungicides/anti-disease treatments, depending on how comfortable people are with various levels of non-organic status. You can make a decision after reading, based on your personal philosophy and what is available to the public where you are.

[gorbelly]

Originally Posted by StrongPlant

And if only I sprayed them with water occasionally this probably wouldn't happen.Plants that are outside are barely affected because of the heavy rains we had.

Originally Posted by StrongPlant

Oh no,I was just reading about this mite and it seems the hot temperature and high humidity are what's aiding this mite's progression...so I guess the water treatment won't help.I also read that it can't survive freezing temperatures so I will try to leave the greenhouse open during winter so the soil can deep-freeze.I will let you know if I find a way to get rid of them without the use of pesticides.Oh and if someone knows a way already please let me know.I am thinking about gassing the greenhouse with CO2 or wood smoke...

Just sprinkling water probably won't do it. Rain helps in that it can prevent mites from getting a foothold on your plants and keeps them from traveling on the wind and whatnot, but it's not toxic to them or anything. Being outside can also help plants because it allows beneficial predators to assist with mite control. Once established, I think it's hard to wash the mites off. They're not like aphids, which are very easy to squirt off of the plant with some water.

I think that what will get rid of mites is dependent on the resistance to various measures in different geographical areas. Also, whether or not they will overwinter depends on climate and the variety of host plants around your property. So perhaps your best bet would be to contact a local university with an agricultural program and see whether they can give you any information.

I don't really live in a good area for the russet mites, so I have no direct experience. Maybe one of the growers here who have had to deal with them will chime in. I suggest you make a new thread with "russet mite" in the subject title and ask that way. You will get more responses from people who know about this issue than if you are at the end of someone else's thread.