4.16.12 Mummy Berry Forecast: Monday, April 16

By Seanna Annis

When are my plants susceptible to mummy berry fungus?

Your plants are susceptible to infection by the mummy berry fungus from when they have 40% of the stems at the crown stage throughout their development.  The flowers and leaves are susceptible at every stage of development past when the bud scales have opened up enough to expose green tissue. While mature mummy berry cups are producing spores in a field, there is the risk of infection. Fortunately, the fungus does not produce spores for the whole season. In different years, mature cups have been found from one week to three and a half weeks in a field, depending upon the weather. Data are being collected this year which will hopefully help predict when cups mature and how long they remain in a field.

Lincoln, Knox, Waldo Counties

Most plants are now susceptible and mature mummy berry cups producing spores have been found in Liberty and Appleton. Numerous pinheads (not yet producing spores) are present indicating the threat of mummy berry infection will still be around for a while.

There were no infection periods over the weekend reported from Appleton and Belfast. Rain is not predicted until Friday, but fog may produce an infection period for the fungus. In the Belfast field, the fog was present for seven hours but temperatures were too cool to produce an infection period.

If your field typically has fog, you may have an infection period this week.

South Hancock County

Plants are susceptible and cups should be present in the field in these areas by this time.

There was an infection period reported at both north Ellsworth and in Ellsworth on Sunday night starting from 6:00 to 10:00 p.m. and continuing until about 8:00 a.m. Monday morning.

If you have NOT applied fungicides to your field, you have until approximately 6:00 p.m on Wednesday to apply propiconazole or fenbuconazole to kill off any infection that may have occurred from the Sunday night infection period.
If you have applied fungicide on or after Sunday, April 8, your plants were protected during this infection period.

Fog may produce more infection periods this week.

Northern Hancock and Washington Counties

Mummy berry pinheads have been found in fields in Aurora, Deblois, Jonesboro, and Montegail Pond.

Plants are approximately 25 to 30% with susceptible flower buds (at the crown stage). With the warm weather predicted for this week, we will have mature mummy berry cups and plants at the fully susceptible stage this week.

Fog can produce conditions for an infection period for the fungus to get into the plants.  The conditions for infection did occur on Sunday night in many areas, BUT there were likely no spores present since mature cups have not been found yet. Therefore there was no infection on Sunday night.

If your field typically has fog and your plants are early, you may have an infection period this week.