What Is Blueberry Mummy Berry – What To Do About Mummified Blueberries

Mummified blueberries are not Halloween party favors, but are actually signs of one of the most destructive diseases affecting blueberries. Mummified or dried out blueberries are only one stage of the disease that, if left unchecked, can destroy an entire blueberry crop. So what exactly is blueberry mummy berry and can it be controlled? The following article contains blueberry mummy berry info regarding blueberries with mummified berries.

What is Blueberry Mummy Berry?

Mummified blueberries are caused by the fungus Monilinia vaccinii-corymbosi. Primary infections begin in the spring, arising from overwintering mummies. At this time, tiny mushroom-like structures called apothecia begin growing from mummified berries. The apothecia release spores, lots of them, which are then carried by wind to leaf buds.

Symptoms of a Blueberry with Mummified Berries

The first symptom of a blueberry with mummified berries is browning along the leaf veins on new leaves. These leaves wilt and curve. A light grey powdery mat of spores develops at the base of the leaf. These spores, in turn, infect flowers and fruit.

Infected berries become slightly ridged, rubbery, and a pinkish-tan in color as the fruit begins to ripen. The interior of the berries contains a grey fungal mass. Eventually, the infected berries fade, shrivel, and drop to the ground. Once the exterior of the fruit sloughs off, the infected berries look like small black pumpkins.

Additional Blueberry Mummy Berry Info

The fungus overwinters in mummified blueberries on the ground and then begins to grow in the early spring as the leaf buds begin to open. Tiny, trumpet shaped brown mushroom cups begin to protrude from the dried out blueberries. This fungal disease many not appear until years after planting. Once it does make an appearance, control measures need to be taken every year.

To control mummy berry, ideally, plant resistant varieties but in lieu of that, thoroughly rake under the blueberries in the early spring prior to bud break to remove as many mummified berries as possible. Do a thorough job, as mummies may be partially hidden in the soil, mulch, or leaf debris. Also, apply a couple of inches (5 cm.) of mulch to bury any remaining fallen mummies.

You may also choose to apply urea, lime sulfur or a concentrated fertilizer beneath the blueberry bushes to try and “burn” out any exposed apothecia. This last cultural practice can be a bit tricky since the application has to be timed just right to be effective.

Keep a close eye on the blueberries. If you see any apothecia, you may need to apply a fungicide. Fungicides also are time sensitive and must be applied at primary infection; early in the spring at bud break. New growth is still susceptible until the shoots are a couple inches (5 cm.) in length so reapplication of the fungicide is crucial. Reapplication should occur about every week depending upon the fungicide. As always, read the manufacturer’s instructions and follow them.

Diagnosis - sick blueberry plant

I ask for help on behalf of my mother, who has a potted blueberry plant in her garden: the label says Vaccinium corymbosum, "giant American blueberry". About a month ago my parents left for a week, and since no one was there to water the plants it completely dried out. After a while it started sprouting again, but never completely recovered: branches have dark/grey marks and leaves soon become red, then develop black spots and fall out. She tried repotting it but without any effect. The blueberry has been watered daily and is exposed to full light during the course of the day. Summer has been quite hot here (almost everyday around 30 C°) but I don't know if that could be a factor. (I'll load pictures as soon as the stack exchange app allows me)

Cold Exposure

The new, young leaves put on by blueberries in the spring are typically tinged with red, but once foliage has established itself on the twig it should exhibit a uniformly bright green hue. Blueberries are fairly cold hardy, growing comfortably within U.S. Department of Agriculture plant hardiness zones 3 through 8, but unseasonably low temperatures can cause leaves to become tinged with red or purple. This discoloration should fade gradually as temperatures warm. If the red leaf color persists despite the return to normal seasonal temperatures, then another culprit is likely to blame.

Final Thoughts

Eating a bowl of blueberries every day can protect you against food-related chronic health issues like diabetes, heart disease, and obesity. What is better than having several shrubs dotting your yard producing these life-saving berries for decades to come? However, you have to put in some work when it comes to caring for the plants including:

  • Ensuring they grow in soil with the right nutritional balance
  • Giving them systemic treatments in advance
  • Clearing the area around them
  • Cleaning the floor of the orchard

The good news is that blueberry plants are forgiving plants so they can bounce back if you catch the problem before it advances too far.

Watch the video: Blueberry Disease Management

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