Overwintering Sick Trees

[Gabler]

Last winter, I moved into a new place, and set up bonsai benches near a mulberry tree. Come spring, the mulberry sent out a flush of vigorous growth, which then promptly died. The tree lost about two thirds of its branches before sending out another flush of growth. Upon closer inspection, it appears to be a leaf blight that attacks both mature leaves and new buds. Unfortunately, it infected my mulberry in training. I've been treating with diluted neem oil and a strong concentration of Daconil, but that only temporarily halts the spread of the blight along the leaves. In other words, the tree is still blighted.

I am not confident the tree will survive the winter. While I work on finding a more effective treatment for the blight, is there anything in particular that you would recommend to help the tree handle the winter? Should I use any additional winter protection, or should I leave the mulberry on the bench to face the winter cold like I normally do? There are some who use neem oil as a dip in the winter to prevent the incubation of insects and fungi. Would that increase or decrease the tree's tolerance to the cold?

I was about to include a picture, but I worry that everyone would comment on the disease itself rather than my narrower question about overwintering a sick tree.

 

[Paradox]

I am not familiar with mulberry but my inclination would be to provide it with some additional protection such as mulching against the house with a wind break as well and hope for the best.

Once you are sure it's done pushing growth, I'd cut off the leaves and dispose of them in the trash. In addition, I would gather up all the leaves from the yard tree and also dispose of those. You don't want any chance of the old leaves keeping that disease in your yard to continue spreading.

I don't believe neem oil will effect its cold tolerance

 

[Wires_Guy_wires]

Neem oil is considered an antifungal because it stops insects spreading fungi. The insects themselves, not the fungi.
If you haven't removed the affected mulberry tree that caused all this, winter protection wouldn't matter because your bonsai will get a new case of the blight.

I would protect it as much as you can while still providing ample dormancy to slow down any disease. But if the daconil doesn't work, which seems to be the case.. I'd also try to investigate the type of blight and search for a solid biocide that does work. From what google tells me, mulberry is affected by bacterial blight. And using a fungicide on a bacterium can be compared to using a rabbit snare on a flea. You might catch a couple in their tracks by accident, but it's better to use something designed for the organism you want to kill.