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Post by Raymond on Aug 21, 2014 9:09:45 GMT
I have a similar problem with 5 of mine I emailed my friend who's husband is a senior judge for the rhs and he asked around they think it is a combination on mildew and viral. They did say to lift and burn the affected plants and also to lift the soil and burn that as well. Or at least sterilise it.
She is also having problems in Suffolk but only with certain ones.
My problem seems to be with all my white decoratives in back garden which leads me to believe it is viral but it has spread as just checked to my Ludwig helfert Orange Dec.
I am new to dahlias but not other plant issues there is a hell of a lot of fungal this year so if viral has weaken plant the fungal will attack. Cannot keep black spot and rust under control with the roses and spraying every fortnight still bad.
Question did you use the same compost for them all when potting up ? I had a bad batch of miracle grow had to rip but loads of spring bedding went mouldy within 6 weeks ? I used Westland for the other bed and it was all fine. I also lost 56 gladioli to gladiolus rot had to lift and burn them all and again miracle grow was used and also my sweet peas ravaged by mildew and again miracle grow was used.
Never buying that again. I will stick to Westland.
I state the above as I just wonder if soil is infected as it has spread front and back.
I wish you the best of luck ! Think we all will need it !
I am fully spraying everything on saturday or mildew supposed to be calm.
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Post by Raymond on Aug 21, 2014 9:17:33 GMT
I was also advise to sterilise all my pots before next season with very dilute jeyes fluid.
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Post by scrumpy on Aug 21, 2014 9:50:22 GMT
Hi let's hope it is not Sclorotina check the affected laterals by cutting the stem off and split it down its length do this away from your soil if it is sclorotina then there will be what looks like a small brown bean and if allowed to go onto the ground will create spores in the soil and create problems for next year and then you have a problem, it is best to burn the plant and the plants next to the infected plants. Or it could just be the Basel leaves are dying off and may be spreading to the upper leaves and this is one of the reasons why it is very beneficial to strip out the Basel leaves once or twice through the season as I do. Mildew get it sprayed straight away to keep it in check. All the best Just checked a stem and it is on the surface only, at present. I regularly remove lower leaves, as you do. I'm beginning to think I may have a mineral imbalance, coupled with mildew. |
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Post by scrumpy on Aug 21, 2014 9:56:07 GMT
I have a similar problem with 5 of mine I emailed my friend who's husband is a senior judge for the rhs and he asked around they think it is a combination on mildew and viral. They did say to lift and burn the affected plants and also to lift the soil and burn that as well. Or at least sterilise it. She is also having problems in Suffolk but only with certain ones. My problem seems to be with all my white decoratives in back garden which leads me to believe it is viral but it has spread as just checked to my Ludwig helfert Orange Dec. I am new to dahlias but not other plant issues there is a hell of a lot of fungal this year so if viral has weaken plant the fungal will attack. Cannot keep black spot and rust under control with the roses and spraying every fortnight still bad. Question did you use the same compost for them all when potting up ? I had a bad batch of miracle grow had to rip but loads of spring bedding went mouldy within 6 weeks ? I used Westland for the other bed and it was all fine. I also lost 56 gladioli to gladiolus rot had to lift and burn them all and again miracle grow was used and also my sweet peas ravaged by mildew and again miracle grow was used. Never buying that again. I will stick to Westland. I state the above as I just wonder if soil is infected as it has spread front and back. I wish you the best of luck ! Think we all will need it ! I am fully spraying everything on saturday or mildew supposed to be calm. Certainly hope it's not a virus. My entire stock will have to go !!! Fresh growth higher up seems to be clean and blooms are fine, so I'm hoping it's mineral related. |
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Post by sweetpea on Aug 21, 2014 10:23:51 GMT
It is strange but when people grow stuff and get to know their plants it is often the case that they will come to the correct diagnosis without much conscious effort. usually in context with the rest of their garden. It is like you get a feel for it. not sure how to explain it otherwise.
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Post by Raymond on Aug 21, 2014 10:51:11 GMT
I am changing most of my dahlias this year so I am ok with binnng mine don't have the quantities you all have so fingers crossed its not a virus. I would give them a feed of sequested iron and try maxi crop seed weed extract you can use as a foliar spray or root feed. Excellent product for the foliage and good general tonic. Although more used for rhododendrons etc.... I have found it very good on my dahlias that early on just would not get going. They are now looking very good.
Good luck !
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Post by scrumpy on Aug 21, 2014 11:13:50 GMT
Yes, got foliar feeds, soluble feeds, 3 insecticides, fungicides, and the kitchen sink to go on in the next few days  That's after all crappy leaves are removed. |
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Post by Raymond on Aug 21, 2014 11:31:22 GMT
Yes, got foliar feeds, soluble feeds, 3 insecticides, fungicides, and the kitchen sink to go on in the next few days That's after all crappy leaves are removed. Your Like me then ! The feeds sprays etc... Cost much more than the plants ! Mildew is a major problem this year. But if blooms good then you have enough potash in the soil. Give them iron ! Full dose of it and a high nitrogen feed next week. it's late to feed with that but your tubors are more important. Take of the bad stuff and cut of the bad stems as well. Then spray with rose clear ultra. Good luck ! Going to do the same with mine and see. Problem with emailing pics never easy to fully see the issue. |
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Post by Raymond on Aug 21, 2014 11:36:19 GMT
Sterilize your secatuers as well ! I use dettol.
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Post by Raymond on Aug 21, 2014 11:53:38 GMT
Sterilize your secatuers as well ! I use dettol. Or dilute jeyes fluid or dilute bleach |
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Post by Deleted on Aug 21, 2014 14:06:24 GMT
Scrumpy be careful with the feed !! I try to stop feeding just as the buds are breaking colour.
Remember if you have mildew feeding your plants will also feed the fungus and all told speed it up. Stick to the fungacide sprayed every 7-10 days and remove infected damaged areas of the plant.
A plant is at its most vulnerable when it is flowering, its delicate mechanism can easily be shocked when its stressed.
Avoid at all costs foliar feeds this time of the year especially if you are suffering from mildew and god knows what else. You also have big time red spider mite, none of our eyes are good enough to see this until its took hold, the back of the leaves should feel like fine sandpaper.
The previous comment about diluted jeys fkuid is quite correct but this should be standard practice whether you have had a problem or not.
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Post by markb on Aug 21, 2014 14:20:47 GMT
Yes, got foliar feeds, soluble feeds, 3 insecticides, fungicides, and the kitchen sink to go on in the next few days That's after all crappy leaves are removed. Your Like me then ! The feeds sprays etc... Cost much more than the plants ! Mildew is a major problem this year. But if blooms good then you have enough potash in the soil. Give them iron ! Full dose of it and a high nitrogen feed next week. it's late to feed with that but your tubors are more important. Take of the bad stuff and cut of the bad stems as well. Then spray with rose clear ultra. Good luck ! Going to do the same with mine and see. Problem with emailing pics never easy to fully see the issue. Careful with that high nitrogen feed at this time of year, that could prove fatal as it will produce quick, lush, soft growth which is even more susceptible to disease. I have sprayed the foliage with a liquid silicone product in seasons past which seems to work. Should be available from a hydroponic supplier. This puts a protective coating on the leaves (top and bottom of leaf is sprayed) so diseases cannot get a hold as easily. Hope you get the problem sorted anyway. |
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Post by Raymond on Aug 21, 2014 15:14:51 GMT
True with the nigh nitrogen feed but we are nearly in September and if plants get fully diseased then their may not be anything left for next year. A risk true. but they need the extra boost. It's what i would try anyway.
With diseased hydrangea, lupins etc... I use the high nitrogen need the extra push of foliage as I normally cut them back anyway.
I would definitely give iron and also foliage spray of maxi crop sea weed. If removing the diseased stems I would also as an extra precaution dust the wounds with a make up brush of sulphur you can even puff the leaves with it will help with any fungal getting more established and into the wounds.
I would take marks advise as he is much more experienced with dahlias that myself.
Good luck and best wishes!
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Post by scrumpy on Aug 21, 2014 17:54:12 GMT
Scrumpy be careful with the feed !! I try to stop feeding just as the buds are breaking colour. Remember if you have mildew feeding your plants will also feed the fungus and all told speed it up. Stick to the fungacide sprayed every 7-10 days and remove infected damaged areas of the plant. A plant is at its most vulnerable when it is flowering, its delicate mechanism can easily be shocked when its stressed. Avoid at all costs foliar feeds this time of the year especially if you are suffering from mildew and god knows what else. You also have big time red spider mite, none of our eyes are good enough to see this until its took hold, the back of the leaves should feel like fine sandpaper. The previous comment about diluted jeys fkuid is quite correct but this should be standard practice whether you have had a problem or not. I stopped feeding 1st August. Don't usually feed again after that. Foliar feed won't be much use I don't think. Most of the leaves will have gone by the time i've finished stripping them off |
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Post by Deleted on Aug 21, 2014 18:04:37 GMT
Don't feed with nitrogen beyond June. Makes the plant more susceptical to fungal diseases later on. I also find that over feeding with potash after mid August, makes my dahlias produce weaker stems. If you've prepared your ground throughly over the winter and spring months, the soil should carry almost all you need to get the plants through the summer months. This combined with a sustained spraying regime throughout the season, coupled with good husbandry, should see you through the season.
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