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This is a Joint Research-Extension project focused on improving control of mummy berry disease in blueberries while decreasing fungicide use. This project will benefit lowbush and highbush blueberry growers, and the people and environment near blueberry fields by decreasing the environmental impact and increasing the economic benefits of blueberry production. <P>Mummy berry disease, caused by the fungus Monilinia vaccinii-corymbosi, is a serious disease in all blueberry species grown in North America. Most lowbush and highbush blueberry growers in ME, NH and MA use a calendar method to determine the timing of at least 2 to 3 applications of fungicide during and post-bud break in the spring to control mummy berry disease. Unfortunately, the calendar method does not take into account variations in weather conditions and development of the plants and fungus, so in most years there is incomplete control of this disease as well as ill-timed and unneeded applications of fungicides. This excessive and unnecessary fungicide use costs money, may have effects on non-target species such as bees, and results in unnecessary environmental contamination. <P>The mummy berry forecasting model (MBFM) incorporates real-time weather events and the stages of phenological development of both the plant and fungus to determine the risk of infection occurring and therefore whether or not fungicides need to be applied. There is a low level of adoption of the MBFM in northern New England (NNE) due to lack of awareness, knowledge of disease dynamics and training of growers.<P> Extension objective E1 is to increase the adoption of the MBFM. We will use workshops, scouting meetings and presentations to introduce and train growers on how to implement the MBFM in their fields. Growers using the MBFM will be supported by guides to the development of the fungus, plants, and disease cycle, factsheets, and information on disease risk both on the web and on a toll-free telephone line during the spring. Participating growers will be surveyed before and after workshops and at annual meetings over two years to determine their use of pesticides and adoption of the MBFM. We expect 200 growers representing 70% of the lowbush production in ME, NH and MA to be trained. And we expect 100 or more growers will adopt IPM practices directly as a result of this project. <P>Conventional northern highbush and lowbush blueberry growers currently use the chemical fungicides propiconazole and fenbuconazole to control mummy berry disease since there are no lower risk (toxicity to animals) or organically-acceptable fungicides that have been demonstrated as effective to control the blight stage of the disease. To control mummy berry disease, organic growers only have two management techniques to rely upon; burn pruning their plants or mulching entire fields both of which decrease inoculum levels.<P> The research objective of this project is to test new, organically-approved (OMRI) materials for control of mummy berry disease. This will aid organic and conventional growers, as well as, the public by making available fungicides with lower toxicity to non-target organisms.
Non-Technical Summary: This is a Joint Research-Extension project focused on improving control of mummy berry disease in blueberries while decreasing fungicide use in northern New England (NNE). This project will benefit lowbush and highbush blueberry growers, the public, and the environment near blueberry fields by decreasing the environmental impact and increasing the economic benefits of blueberry production. Mummy berry disease affects all species of blueberry and can decrease yield up to 50% in highbush and 100% in lowbush blueberries Currently the majority of growers in Maine, New Hampshire and Massachusetts are applying up to 3 fungicide applications using a calendar schedule which often results in incomplete control and unnecessary fungicide applications. The adoption of a mummy berry disease forecasting model (MBFM) will produce science-based pest management that safeguards human health and the environment and promotes economic benefits for growers. Our extension goal is to increase the adoption of the MBFM by blueberry growers in NNE. Growers and consumers are also interested in reduced-risk fungicides and cultural techniques for managing disease. Our research goals are to determine the interactive effects of weed pressure, fertility and fungicide treatment on severity of mummy berry blight on lowbush blueberries, and test low-animal toxicity fungicides and cultural amendments for their disease control efficacy. <P> Approach: Research: The effectiveness of lower risk fungicides and organically acceptable materials for the control of mummy berry disease will be tested in two crop fields each in yr1 and yr 2 . Each treatment will be applied in plots 2 m wide and 10 m long in a replicated complete randomized-block design with 8 blocks. Treatments will include an untreated check, and currently used fungicide, propaconizole at the recommended rate, and low risk fungicides and organic materials applied at their recommended rate. In June, the incidence and severity of mummy berry blight and will be determined for 70 stems along a transect through the middle of each plot. In August before harvest, the percentage of stems with mummy berries and the number of mummy berries per stem will be determined for 70 stems in each plot. Yield will be estimated by harvesting a 45 cm wide strip down the center of each plot. Disease incidence and severity is proportional and so will be normalized by applying a square-root of the arc-sine transformation of the data. Analysis of variance will be used to determine the effectiveness of the treatments on mummy berry disease control and yield.