Archives: Plant Answer Line Q & A

We have 5 acres that are covered in 50-year-old fir and cedar forest,
with lots of salal and evergreen huckleberry. The huckleberries have
what looks like mummy berries that I have seen in photographs of
blueberries before. They have a dry grey peeling that feels like old
garlic skin with a very hard brown inside. There doesn’t appear to be
any problem with the foliage. These bushes are naturally growing, and
are all over through the property. Mulching and cultivation would be
nearly impossible on this scale, and I’d really prefer not to spray if
possible. Can you suggest a safe method of control that would be
possible on this large scale? Or is this something that nature will take
care of on its own? Or do we even need to worry about it since we don’t
harvest the berries? I can live with a few shriveled berries. I just
don’t want it to spread wildly or kill off half of our underbrush.

 

If mummy berry is what you are seeing (and it does sound like it), it is
caused by a fungus which overwinters in the fallen berries, so anything
you can do to collect them might help. The following, from Ohio State
University Extension, describes the life cycle of this fungal problem.

The Organic Gardener’s Handbook of Natural Insect and Disease Control by
Barbara Ellis (Rodale, 1996) recommends removing the berries and in
spring, cultivating around the bushes to bury any fallen mummies, or
adding mulch to cover fungal spores.

Beyond the good hygiene of removing the fallen fruit, there may be a
chance that wettable sulfur spray might help, as described in this information from McGill University. Excerpt:

“Clean cultivation can reduce the incidence of mummy berry disease. This
practice destroys the fallen mummified fruit, which harbors the inoculum
for the next season’s infection. Wettable sulfur sprays have also been
effective in reducing mummy berry infection. In New Jersey, researchers
used three sprays roughly one week apart with the first spray timed for
leaf emergence in the spring.”

However, I found Ohio State University contradicting this information,
indicating that organic fungicides such as sulfur and copper were
ineffective against mummy berry.

Here is additional information from National Sustainable Agriculture
Information Service. Excerpt:

This fungus overwinters in mummified berries that have fallen to the
ground. Sod or moss directly under the plant will contribute to spore
production. To control this fungus, remove infested fruit (“mummies”)
from the plant, rake and burn mummified berries, or cover the fallen
berries with at least two inches of mulch. Cultivation during moist
spring weather will destroy the spore-forming bodies. Strategies that
lead to early pollination of newly open flowers may be useful in managing
mummy berry disease in the field, since studies show that newly opened
flowers are the most susceptible to infection and that fruit disease
incidence is reduced if pollination occurs at least one day before
infection.(Ngugi et al., 2002)

The fungus survives the winter on dead twigs and in organic matter in the
soil. The disease is more severe when excessive nitrogen has been used,
where air circulation is poor, or when frost has injured blossoms.
Varieties possessing tight fruit clusters are particularly susceptible to
this disease. Remove dead berries, debris, and mulch from infected plants
during the winter and compost or destroy it. Replace with new mulch, and
do not place mulch against the trunk of the plant.

I’m afraid there is not an easy solution for such a large expanse of
huckleberries. Then again, if you are not concerned about harvesting the
fruit, then you can probably just let it be. Since the fungus seems to be
a problem primarily for plants in the blueberry family, I do not imagine
it will harm other plants on your property.