Photos of Plant Diseases

[Diane Whitehead]

Joseph has offered to create a forum for diseases.

Make a list of about 50 threads about diseases, and I'll create a forum for them.

The only disease I have encountered is late blight on tomatoes, but I imagine other vegetables might also have diseases.

Can we make a list of diseases, and then next season we can take photographs.

I'll start:

Tomato   

early blight
late blight

[Steph S]

Here is a handy list of pea diseases:

https://en.wikipedia.org/wiki/List_of_pea_diseases

[Klaus Brugger]

For those who don't know these sites yet:

The American Bugwood Network image sites have many helpful pictures of diseases/pests among other things.

Likewise, the European EPPO Global Database provides pictures and in addition information about distribution, host plants etc.

[Diane Whitehead]

Thanks!

Here are lots of photos of late blight on tomatoes:

https://www.ipmimages.org/browse/subthumb.cfm?sub=10796&cat=16

[Steph S]

That page of late blight pics is amazing, Diane.
Great that they show it on potatoes too, and how to test using a potato.

I have seen late blight turn up in a bag of potatoes of commerce from time to time.  Didn't know what it was.

[Diane Whitehead]

Linda Gilkeson, an entomologist who lives nearby, has published books and a website on insects and diseases.

Here are foliage diseases:

http://www.lindagilkeson.ca/foliage.html#143

[William Schlegel]

https://workspace.oregonstate.edu/course/master-gardener-series-plant-pathology

This $45 continuing education course online might be useful for folks who just want to learn a bit more about plant pathology. I've successfully avoided the whole discipline for a very long time mainly by shrugging and moving on from genotypes and species that don't do well for me and growing a wide diversity of plants so that the loss of one variety or species is never that disappointing. However, it has some practical applications for plant breeding- like it would be interesting to successfully identify the few tomato diseases I do have (assuming I do have a few of the milder types) even though they don't seem to kill my tomato plants.

[Steph S]

Plant pathology is a hard thing to master without a lab and without an experienced guide to learn to identify diseases really readily in the field.   
It's also something that we have to deal with as breeders. 
At this point the longer term impacts of climate change are starting to become clear, to the point where we can have expectations in the near to medium future of conditions that are changing in our farms and gardens.  Hotter summers are one but humidity is a big one.  There's just going to be more humidity in the atmosphere because of rising heat, and that means occasionally heavy or damaging rains in dry areas, but in my area it means lots of humid times especially when hot, and the spore environment is changing and there are going to be more years with serious fungal blight.  2023 was really bad for fungal unfriendlies on a number of susceptible crops here, and friends/groups across Canada and the US are reporting surges of disesase that made it a bad year for their crops.
I suspect there is late blight on a lot of potato crops this year.  One week at the store, they had the usual brand of spuds on sale, but there was a lot of white patches on the bags, I passed on those.  Two weeks later the regular brand is nowhere to be seen, we have another brand that we usually see late spring or early summer when the other runs out.  These bags are not covered in spores but a lot of the spuds have dings in them that are grey/white and looks like the start of blight to me.  I would not be surprised to see a potato shortage before winter is out, because any bit of blight in a bag will rot the crop quickly.
So I'm definitely planning to start work with some designed resistance tomatoes next season - Randy Gardiner's work looks like an excellent place to start.   
I have some seeds from another gardener's save of Mountain Magic, which I guess are F2's.  So I expect some variation already before crossing with our house lines that are locally adapted.  I will be sourcing some commercial F1 material as well, for the known traits to start with.  And even though I don't have LB here (yet) I have seen it on potato crop before (and the reason I stopped growing my own potatoes) so the clock is probably just ticking.  So it's fine by me to start with lots of stacked resistances, and hope the lucky genes are present when the day comes, is about as good as I can manage on site.
The thoughts of a plant pathology course definitely crossed my mind, although the moment isn't yet for me, maybe soon penned in on the timeline.