Wow good work I knew it attacked the new growth, that's a good idea to cut into it's supply to the bacterial infection it has to grow past it but not compartmentalize it nice job
The fruit is hight in pectin but Watch out for thorns on the branches. the wood has a beautiful burnt orange color and strong too, one bow made from this wood was worth a horse and a blanket. http://www.eattheweeds.com/maclura-pomifera-the-edible-inedible-2/
If the tree is mature enough it might fight it back, I believe it's bacterial not fungal so it does matter what you put on it it needs to grow up past it but not grow so much the new growth gets it again, proper cuts while cleaning your tools allot otherwise your spreading the blight.