The following represents various compilations on the disease mummy berry in blueberries. Links will take you to various educational sites on the disease.
MUMMY BERRY DISEASE OF BLUEBERRY
http://ipmwww.ncsu.edu/small_fruit/mummybry.html
Mummy berry caused by Monilinia vaccinii-corymbosi is a fungal disease of major importance in the northern and southern highbush blueberry regions, where it causes considerable damage to the fruit. In addition, severe blighting of the leaves, shoots, and flower buds of rabbiteye cultivars Delite, Southland, Premier and Tifblue has occurred in North Carolina plantings.
Symptoms and Disease Development
In early spring, small cup-shaped spore-bearing structures called apothecia are produced from sclerotia. In southeastern North Carolina, overwintered sclerotia break dormancy around the first week in February and develop mature apothecia about one month later. Spores (ascospores) produced by the apothecia are liberated during cool, wet weather and are carried by air currents to the young emerging leaf and flower shoots. These spores infect and blight the young shoots, and secondary spores (conidia) are produced in great abundance on the blighted leaves. These conidia are carried by wind or insects to open flowers where the ovaries become infected. Prior to harvest, infected berries become light cream-color rather than normal blue and drop to the ground. These infected fruit, if left on the ground, form overwintering sclerotia and provide a source of disease the following year.
CONTROL
Avoidance can be used by anyone who is producing blueberries in an isolated location. Unless the disease is present in wild or cultivated bushes nearby, growers and homeowners can successfully avoid mummy berry by planting only dormant (leafless) bare-rooted plants. This avoids introducing sclerotia or infected leaf shoots into the new planting. If a new planting is established with potted plants, rake off and destroy any plant debris on the surface of the soil in the pot to prevent planting of sclerotia along with the new bush. This is especially important with plants purchased from other states, since new species or races of mummy berry might be introduced into NC as sclerotia in pots.
Fungicidal control, especially the use of triforine (Funginex) has proven very successful. Benomyl (Benlate) is also used in bloom to prevent secondary infection. Consult product labels or the blueberry spray schedule in the NC Ag Chem Manual for specifics.
Sanitation was the traditional means of controlling this disease for many years. Growers hand-raked fields to remove overwintering sclerotia (mummies). While raking is no longer practical on a large commercial scale, growers can still reduce disease by disking to bury sclerotia and by clean cultivation. Burying mummies at depths of one inch or more will help to prevent germination.
Resistance: All highbush cultivars appear to be susceptible to the mummy berry phase to some degree. Some of the most resistant cultivars are among the newly released southern highbush types (Bladen, Reveille). Note that the fruit infection stage of mummy berry has not been observed to occur on rabbiteye blueberry (Vaccinium ashei) in NC. This means that growers in the piedmont of NC may be able to avoid mummy berry by planting only this species, as they typically do. Rabbiteye blueberries DO get fruit infections in Georgia and Mississippi, perhaps indicating the existence of another species or race of the mummy berry fungus in those areas.
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Mummy Berry Disease Attacking Blueberries In Georgia (summer radio broadcast in Georgia)
Some mummies are attacking blueberries in Georgia.
The attacking mummy is a disease called mummy berry, which is caused by a fungus. Once infected blueberries harden and become mummified during the freeze-drying process, making products with frozen Georgia blueberries unmarketable. Economic losses suffered by the blueberry industry in Georgia caused by this disease could be quite high. But since the mid-90s, scientists with the University of Georgia College of Agricultural and Environmental Sciences have been conducting research to learn more about this disease. "Better understand the life cycle of this pathogen in Georgia, specifically in southern Georgia where most of the blueberries are grown, in other words how it survives when it becomes active in the spring, when the most important infection periods are." That was Harald Scherm with the College of Agricultural and Environmental Sciences, who adds research is also taking place to develop a reliable way to detect mummy berry disease in blueberry packing houses. College scientists are also working to get emergency labels granted on certain fungicides to help growers control this disease in fields. John Harrell, University of Georgia College of Agricultural and Environmental Sciences, reporting from Tifton.
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In Oregon: << http://eesc.orst.edu/agcomwebfile/edmat/em8538.pdf >>
Benlate, Captan, Bravo and Ziram are used.
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BLUEBERRY DISEASE MANAGEMENT
From the University of Connecticut: << http://www.hort.uconn.edu/ipm/fruit/htms/bluedismgt.htm >>
Management of Mummy berry. Management of the disease includes several strategies, the most important being sanitation. Mummies should be raked up and discarded in smaller plantings. In larger plantings, the mummies should be buried by cultivating between the rows or by adding two inches of mulch. An application of 50% urea prills in the spring helps speed the degradation of the mummies via soil microorganisms. The susceptible cultivars Bluehaven, Bluegold, Coville, Northblue and Sierra should be avoided. Bluejay, Darrow, Duke, Elliott, Jersey and Stanley have resistance to the shoot blight phase of the disease. Fungicide applications should be targeted against primary infection; the first application at the green tip growth stage should be followed by a second application 10 days later. Additional fungicides can be applied during bloom to control secondary infection. In general, any diseases caused by fungi that affect the above-ground portion of the plant can be more effectively managed by proper planting and regular pruning to allow for good air circulation around the plants. In addition, if plants must be irrigated, this practice should be done in the early morning hours to allow for rapid drying of the leaves, flowers and berries.
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Extracted from the West Virginia University Extension Service, 1990, by Juanita Popenoe and Richard K. Zimmerman << http://www.wvu.edu/~agexten/hortcult/fruits/groblueb.htm >>
Mummy Berry is caused by a fungus (Monilinia vaccinii-corymbosi). The fungus overwinters in mummified berries that have fallen to the ground. With moisture in the spring, these mummified berries produce small, brown, cup-shaped fruiting bodies that produce spores carried by the wind and insects to the young, succulent shoots. Sod or moss directly under the plant will contribute to the spore production. The infected shoots will curl up, turn brownish black and die. The fungus in the twig then produces a second kind of spore that infects the newly forming berries. The berries will not show signs of the infection until the other berries start to turn blue. At this point, the infected berries will turn beige-brown and start to shrivel to a mummy. To control this fungus, rake and burn the mummified berries, or cover over the fallen berries with at least two inches of mulch. Cultivation during the moist spring weather will destroy the spore forming bodies in the spring. Another technique is to apply urea and sand (50/50) at the rate of 200 lbs. per acre in the spring when the cup-shaped fruiting bodies appear.
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EMERGENCY USE FUNGICIDE FOR MUMMY BERRY IN VERMONT
Compiled by Vern Grubinger, University of Vermont Extension
(802) 257-7967 or vernon.grubinger@uvm.edu
<< http://www.uvm.edu/vtvegandberry/newsletter/05012001.html >>
Mummy berry disease has been a serious problem in highbush blueberries at some locations in Vermont. In early spring, overwintering sclerotia of the fungus produce small cup-shaped spore-bearing structures (mushrooms) called apothecia. Spores produced by the apothecia (called ascospores) are released during cool wet weather and carried by the wind to emerging blueberry leaf and flower shoots. These shoots become infected and blighted (primary infection). Secondary spores (called conidia) are produced in abundance on blighted leaves, and are carried by wind and insects to open flowers, infecting the ovaries (secondary infection). Infected flowers produce berries that become cream colored rather than normal blue, and prior to harvest infected berries drop to the ground. These infected fruit, if left on the ground, form overwintering sclerotia that provide a source of disease the following year.
This year, EPA has granted a ‘state emergency exemption' for use of INDAR 75 WSP fungicide (fenbuconazole) to control mummy berry disease on blueberries in Vermont from April 1 to September 1, 2001. Indar 75 WSP has been shown to be effective against both primary and secondary mummy berry infection. It should be applied at a rate of 2 ounces (one Water Soluble Pouch) per acre, by ground. Begin applications at early green tip and make subsequent applications at 10 to 14 day intervals. Restrictions include: Applications through any type of irrigation system are prohibited. Do not make applications within 30 days of harvest. Do not make more than 5 applications or apply more than 10 ounces per acre per year. Do not use any spray adjuvants with INDAR 75WSP. Do not graze livestock in treated areas or feed cover crops grown in treated areas to livestock. Do not make applications within 75 feet of streams, rivers, ponds, lakes, or reservoirs. The Re-Entry Interval (REI) after application is 12 hours.
You must have the special state label in your possession at the time of application. Contact me for a copy. Also, EPA has asked the state to maintain a record of the names of growers using Indar and the quantity they apply. Please report this information to me.
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