Blueberry IPM - Mummy Berry

ID/Life Cycle:

The first symptom of this disease is browning along the major leaf veins on newly emerging leaf clusters. The leaves wilt quickly and the tips of the twigs bend to resemble a shepherd's crook. A light gray powdery layer of spores develops at the leaf base. Infected green berries appear healthy but cutting them open reveals a white fungal growth inside. When berries start to ripen, infected berries appear pinkish tan and slightly ridged. They feel rubbery and contain a gray to black fungal mass inside. Infected berries eventually become faded, shrivel up, and fall to the ground. After the fruit skin has weathered off, the mummified berries look like tiny black pumpkins.

The fungus overwinters in the mummified fruit on the ground. In early spring, trumpet-shaped fruiting bodies produced on the mummies eject windborne spore that infect young shoots. Frost may increase susceptibility of blueberry shoots to infection.  Spores are produced on blighted shoots and are carried to flowers by wind, rain, and pollinators (bees), resulting in fruit infections. Mummies that fall to the ground provide inoculum for the disease in the following year. 

Damage:

The fungus infects and invades the developing fruit rendering it unmarketable.

Management Strategies

Monitoring:

Consult scouting records from previous years to determine if build-up of this disease is indicated.  Monitor weather conditions to identify likely infection periods.  Scout fields beginning at budbreak for symptomatic tissue.

Cultural/Biological tactics

• Plant resistant varieties whenever possible.
• Prune bushes to open the canopy to light, air, and spray penetration.
• Cultivate beneath plants in fall and again in early spring to disrupt overwintering inoculum.
• Apply a 3-4” layer of mulch material over the soil surface in early spring before fruiting bodies emerge to create a physical barrier to spore release.
• Application of 46% urea at a rate of 200lbs/A prior to budbreak can decrease the number of viable fruiting bodies.

Chemical tactics

• Refer to the New England Small Fruit Management Guide for specific materials and rates recommended for managing mummy berry.

•  Apply recommended fungicides at budbreak if scouting and weather monitoring indicate risk of infection.
• Time fungicide applications closely to frost/freeze events that predispose tissue to infection.
• Repeat fungicide applications at recommended intervals if weather conditions are conducive to infection.
• Rotate fungicide materials from different FRAC groups to avoid promoting the development of resistant strains of this disease.

Date: March 2020
Author(s): Angela Madeiras & Sonia Schloemann, UMass Extension

Additional information available on the MYIPM app: https://apps.bugwood.org/apps/myipmseries/

Note: This information is for educational purposes only and is reviewed regularly for accuracy.  References to commercial products or trade names are for the reader’s information. No endorsement is implied, nor is discrimination intended against similar products. For pesticide products please consult product labels for rates, application instructions and safety precautions. The label is the law.  Users of these products assume all associated risks.

This work was supported in part by funding provided by USDA NIFA Extension Implementation Program, Award No. 2017-70006-27137