Southern blight in the north?

ddsack · June 23, 2006

I have two plants, a Black Cherry and a Snow White cherry that were growing next to each other, that have succumbed to what looks like Southern Blight. Is this possible in northern Minnesota? The damage is only on the stem at ground level. I have never had this disease before, and am trying to figure out where it came from. Is there another disease that basically looks like dry damping off on a healthy 1/4 to 3/4 inch diameter stem?

The plants were growing in a raised bed, with sandy soil that dries out very quickly, but don't get sun til around 11AM, though it is strong the rest of the day til evening. Our temps have varied from from high 60's to mid 80's dropping down to 50's at night. We are very dry, most of the rain passes us by, and the humidity level has not been particularily high. Typical summer weather for here.

I use newspaper collars to protect from the many cutworms that love this sandy soil. When I inspected the grey and shrunken stems at ground level, I blamed the collars for keeping out ventilation on the stems and wicking up water. (Even though I have used newspaper for years with no problem.)

I cut off the white cherry above the bad part and re-rooted in a milk jug. I ended up tossing the black cherry along with the surrounding soil. I have now replanted the white cherry top, along with a stringy pot-bound left-over black cherry seedling into the same spots. I am curious to see if the two new plants will develop the disease as well, even though I did remove some of the surrounding soil.

When I hurriedly removed the newspaper collars from the remaining plants in the back garden (this was all about 3 weeks after they were set out and growing great guns) I noticed that only two other plants in the infected bed had a little stem damage, but I thought I would see if "airing" them out would help. So far, the Stupice, the Riesentraube and the Jaune Flammee are doing very well, and what grey shrunken area they had, has stayed in place and not girdled the stem. Since it is too late to replant anything anyway, I thought I would let the disease progress, if it does, and make sure to let it lie fallow or replant with something else the next year or two.

Here is a pic of one of the discarded stems, click to enlarge:

Is this Southern blight, or a copycat something else?
I am wondering if the disease could have come in the potting soil mix that I combined with seed starter mix when I re-potted seedlings for the last time. And the wet newspaper collars incubated it? So far it has only affected the one bed, out of over 60+ plants. (Knock on wood!!)

Would saturating the soil line with Daconil make any difference in retarding the disease in the partially damaged plants that seem to be holding their own? They have not deteriorated further in the last 2 weeks.

feldon30 · June 23, 2006

It doesn't help you now, but soilborne diseases are reduced by using mulch. Straw, newspaper, herbicide-free grass clippings (not weed-n-feeded).

MsCowpea · June 23, 2006

That looks like the type of damage that occurs when your mulch is touching the stem and rots it.

**Mischka** · June 23, 2006

Quote:

Originally Posted by ddsack

Would saturating the soil line with Daconil make any difference in retarding the disease in the partially damaged plants that seem to be holding their own?

Daconil (chlorothanlonil) works by coating the outer leaf surface to seal out fungal spores from attaching. It doesn't "kill" the spores.

Spraying the soil line with it would be a waste of your time (and Daconil).

ddsack · June 24, 2006

Ms Cowpea - I hope you are right. I have never had this happen before, but I would prefer to think the damage is created by conditions within too high and too tight newspaper collars on these particular plants , than from something in the air or soil that I have less control over. I will be watching to see if the replacement plants in those sites develop the symptoms.

Mishka - thanks for the Daconil comments, I did not know about the blockage effect vs the killing effect.

June 23, 2006	#1
ddsack Tomatovillian™ Join Date: Jan 2006 Location: Northern Minnesota - zone 3 Posts: 3,220	Southern blight in the north? I have two plants, a Black Cherry and a Snow White cherry that were growing next to each other, that have succumbed to what looks like Southern Blight. Is this possible in northern Minnesota? The damage is only on the stem at ground level. I have never had this disease before, and am trying to figure out where it came from. Is there another disease that basically looks like dry damping off on a healthy 1/4 to 3/4 inch diameter stem? The plants were growing in a raised bed, with sandy soil that dries out very quickly, but don't get sun til around 11AM, though it is strong the rest of the day til evening. Our temps have varied from from high 60's to mid 80's dropping down to 50's at night. We are very dry, most of the rain passes us by, and the humidity level has not been particularily high. Typical summer weather for here. I use newspaper collars to protect from the many cutworms that love this sandy soil. When I inspected the grey and shrunken stems at ground level, I blamed the collars for keeping out ventilation on the stems and wicking up water. (Even though I have used newspaper for years with no problem.) I cut off the white cherry above the bad part and re-rooted in a milk jug. I ended up tossing the black cherry along with the surrounding soil. I have now replanted the white cherry top, along with a stringy pot-bound left-over black cherry seedling into the same spots. I am curious to see if the two new plants will develop the disease as well, even though I did remove some of the surrounding soil. When I hurriedly removed the newspaper collars from the remaining plants in the back garden (this was all about 3 weeks after they were set out and growing great guns) I noticed that only two other plants in the infected bed had a little stem damage, but I thought I would see if "airing" them out would help. So far, the Stupice, the Riesentraube and the Jaune Flammee are doing very well, and what grey shrunken area they had, has stayed in place and not girdled the stem. Since it is too late to replant anything anyway, I thought I would let the disease progress, if it does, and make sure to let it lie fallow or replant with something else the next year or two. Here is a pic of one of the discarded stems, click to enlarge: Is this Southern blight, or a copycat something else? I am wondering if the disease could have come in the potting soil mix that I combined with seed starter mix when I re-potted seedlings for the last time. And the wet newspaper collars incubated it? So far it has only affected the one bed, out of over 60+ plants. (Knock on wood!!) Would saturating the soil line with Daconil make any difference in retarding the disease in the partially damaged plants that seem to be holding their own? They have not deteriorated further in the last 2 weeks.

June 23, 2006	#2
feldon30 Tomatovillian™ Join Date: May 2006 Location: Rock Hill, SC Posts: 5,346	It doesn't help you now, but soilborne diseases are reduced by using mulch. Straw, newspaper, herbicide-free grass clippings (not weed-n-feeded). __________________ [SIZE="3"]I've relaunched my gardening website -- [B]TheUnconventionalTomato.com[/B][/SIZE] * [I][SIZE="1"]*I'm not allowed to post weblinks so you'll have to copy-paste it manually.[/SIZE][/I]

June 23, 2006	#3
MsCowpea Tomatovillian™ Join Date: Jan 2006 Location: S. FLorida / Zone 10 Posts: 369	That looks like the type of damage that occurs when your mulch is touching the stem and rots it. __________________ "When we kill off the natural enemies of a pest we inherit their work." Carl Huffaker

June 24, 2006	#5
ddsack Tomatovillian™ Join Date: Jan 2006 Location: Northern Minnesota - zone 3 Posts: 3,220	Ms Cowpea - I hope you are right. I have never had this happen before, but I would prefer to think the damage is created by conditions within too high and too tight newspaper collars on these particular plants , than from something in the air or soil that I have less control over. I will be watching to see if the replacement plants in those sites develop the symptoms. Mishka - thanks for the Daconil comments, I did not know about the blockage effect vs the killing effect.