Mummy Berry Post #6: May 27th, 2021

Thursday, May 27, 2021

 A quick update on Mummy Berry Development:

 

We want to share an important update regarding our Highbush Monilinia monitoring. As of May 26, all the mummy berries have dried up and cannot release ascospores (Figure 1). What we see now, are the symptoms of ascospore damage which were released earlier in the season.




Figure 1(above). Dried mummy berries.  

 

In early maturity varieties, shoot blight symptoms such as drooping of affected shoots, followed by brownish purple discoloration of the upper sides of the midribs and lateral veins of affected leaves and flower cluster blight can be observed (Figure 2, and 3). 









Figure 2 and 3(above). Twig blight caused by Monilinia.

The tufts of grayish conidia appear along the petioles, midribs of affected leaves, and on the infected peduncle or flower pedicels (Figure 4). These conidia that are forming on the diseased leaf shoots and flower clusters will now be spread further by bees, flies, and wind to open flowers where they will grow down the flower style and eventually form a mummy berry. 

 




Figure 4(above): Grayish mycelium of the fungus on the petioles.

  • Most of mid and late maturity varieties are clean but regular scouting of the fields is highly recommended to help plan for next years mummy berry management.
  • Usually, fungicide sprays targeted to prevent these flower infections are not cost effective but can be practiced. The pruning of branches is not recommended but the easiest way to prevent further conidial spread would be to simply pick off diseased leaf shoots and flower clusters and drop them to the ground or collect them in a bag. This would limit the spread of conidia that are present now.  

Mummy Berry Post #5: May 20th, 2021

Thursday, May 20, 2021

 A quick update on Mummy Berry Development:

 

Floral bud counts on May 19, 2021 from the Annapolis Valley Nova Scotia.

All the varieties in the valley are beyond F2 stage (Figure 1 and 2).

 

 


Figure 1(above). Floral buds of Burlington.

 


Figure 2 (above). Floral buds of Duke.

Most of the apothecia cups (the fruiting bodies that produce the infectious ascospores) were mature and have dried up, eliminating the risk for infection (Figure 3).

 


Figure 3(above). Drying apothecial cups

Though the weather conditions will be conducive for the next coming week, new infection events from ascospores will not occur. Farms with a history of mummy berry should have put on 1-2 protectant sprays that would protect the plants from further infections.

 

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

As a reminder, these recommendations are based on conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. Infection periods only occur when bud development has reached the F2 stage, monilinia apothecial cups are present, and temperature and moisture levels are ideal.