Wednesday, June 30, 2010

Mulberries and Popcorn Disease

Ah, late June and the taste of mulberries and cream. One of my favorite bits of summer. Every day the boy and I go out and pick a big steel colander worth of fresh, ripe black mulberries. Then we put them in the freezer. The next day, we whip them up in the food processor, add a bit of milk and sugar, and voila! Ice Cream (like substance)!

I have been noticing that since last year, there were a lot of fruits that seemed to be turning gray, swelling up, and rotting on the tree. And they were always so huge, it really bothered me. "Why are all the good ones dying?" I thought. So I took to cutting them off and letting them drop to the ground.
Now let me tell you, if you have a mulberry tree, and some of the fruit turns gray/white and large, don't cut it and let it lay on the ground! Apparently, there is a fungus out there (Ciboria carunculoides) that gives the trees a disease called popcorn disease. It is perpetuated by letting the infected fruit fall to the ground! D'oh! So, from next year, all the infected fruit will be collected on a tarp, and burned in a slow fire. And hopefully, after that, it will grow less and less each year.
More info on popcorn disease- apparently white mulberries and hybrids are the most susceptible to the fungus, which overwinters in the soil, and releases spores in the spring to infect the fruit. After it infects the fruit, it replaces the carpels with sclerotia (whatever that means), which causes them to swell well beyond normal size- that is why it looked like only the biggest fruit got it. They weren't supposed to be so big, it was just the fungus.

At any rate, sanitary practices should control my disease from the year after next. And I still have quite a lot of fruit from the tree this year.


  1. I have a horrible problem this year and will be spraying with Bordeaux mixture often next spring. It's just called "bordeaux mixture".

  2. How did the mulberry popcorn disease work out for you? I noticed a few white berries on my tree last year, then this year it has taken over and wiped out the whole crop! Major disappointment...

    1. I cut all the branches off and let it grow out new sprouts from the 4 foot high trunk. But then the goats escaped, and.... well, I think it has given up the ghost. I will get another and plant it far from that place and see what happens.