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Controlling Mummy Berry in Organic Blueberry Systems
By: Bradley J. Burbaugh, Agriculture & Natural Resources Agent, UF/IFAS, Duval County Extension Service
Blueberry production in North Florida has increased significantly since the mid-1970's. Thus, blueberry is one of the most economically important fruit crop in Northeast Florida . A number of factors indicate considerable near-term potential for expansion of organic blueberry production: 1) higher prices for organic produce in general; 2) the need for alternative sources of income for farmers; 3) increased consumer demand for blueberries fueled by widely publicized health benefits (McCord 1999). If some significant production limitations can be conquered, organic production can become a significant part of the blueberry industry in the southeast.
This article will provide a review of timely mummy berry research presented at the Southeast Fruit and Vegetable conference in Savannah , Georgia . Most experts recommend the use of a rabbiteye cultivar in organic systems because it has the least amount of disease pressure.
However, all rabbiteye cultivars appear susceptible to mummy berry disease caused by a fungus, Monilinia vacinii-corymbosi . This disease is widespread in the Southeast and causes two symptom types: shoot blight in early spring and fruit mummification in early summer. In the absence of chemical management options, mummy berry is a major constraint to organic blueberry production. Here are some recommendations for controlling mummy berry.
The mummy berries are unable to germinate when covered with soil to a depth of 1” (Milholland 1974); thus, cultivation in the alleys between the plant rows reduces disease pressure. Unfortunately, most mummy berries rest near the crowns of the blueberry bushes where cultivation equipment cannot be used without damaging the shallow roots of the plant.
Sufficiently thick layers of pine bark or other mulch may suppress mummy berry by inhibiting germination on the ground. However, following decomposition of the mulch, germination of mummy berry may be enhanced due to the better water holding capacity of the mulch.
Few biofungicides approved for use in organic production have been tested against mummy berry. Of the three that are approved Serenade has shown fairly consistent control of both shoot blight and fruit mummification (Scherm, 2006). Mummification occurs during the bloom stage. Therefore, an application of Serenade at 10% bloom repeated every 7 days up to 90% bloom is most effective. It is better to start spraying later rather than stopping too early. Follow the Serenade label for spray formulations.
Mummy berry can be particularly troublesome in organic productions systems, but through early scouting and following the aforementioned recommendations producers can decrease crop losses.
The use of trade names in this publication is solely for the purpose of providing specific information. It is not a guarantee or warranty of the products named and does not signify that they are approved to the exclusion of others of suitable composition.
