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This Joint Research-Extension project is to improve 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 time at least 2 fungicide applications during bud break in the spring to control this disease. The calendar method does not consider 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 unnecessary fungicide use costs money, may have effects on non-target organisms, and results in unnecessary environmental contamination. The mummy berry forecasting model (MBFM) incorporates real-time weather events and the stages of development of both the plant and fungus to determine the risk of infection occurring and therefore whether or not fungicides need to be applied. <P>There is a low level of adoption of the MBFM in northern New England due to lack of awareness, knowledge of disease dynamics and training of growers. Extension objective E1 is to increase the adoption of MBFM. We will use workshops, scouting meetings and presentations to introduce and train growers on how to implement MBFM in their fields. Growers using MBFM will be supported by disease risk information on the web and at a toll-free telephone line during the spring, and factsheets on the disease cycle, MBFM, and development of the fungus and plants. Growers will be surveyed pre and post- workshops and at annual meetings over 2 years to determine their use of pesticides and adoption of 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 Northeastern blueberry growers currently use conventional fungicides to control mummy berry disease, since there are no lower risk or organically-approved fungicides that are effective controls. Organic growers only have the expensive methods of burn pruning or mulching entire fields to decrease inoculum for control. <P>Research objective 1 is to test new, organically-approved materials for control of this disease. This will aid organic and conventional growers and the public by making available fungicides with lower toxicity to non-target organisms. In an organic field in 2005, there were significantly higher levels of mummy berry blight and a higher percent cover of weeds in plots with minimal weed control and high levels of fertilizer than plots that were treated with half the fertilizer or not-fertilized. <P>Research objective 2 is to conduct field experiments to determine the interactions among the above management practices and their consequences on disease and yield.
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: Extension: The mummy berry forecast model (MBFM) developed by Paul Hildebrand and Rick Delbridge tracks fungus and plant development and weather conditions to determine the probability that ascospores have infected the plant. Grube and Schloemann will come to ME in 2010 for training in the MBFM and then Yarborough and Annis will visit NH and MA in 2011. We will use grower meetings, scouting schools, winter workshops and presentations to train growers in the MBFM. Weather and fungus monitoring stations will be established each year (5 in ME, 2 in NH, 1 in MA) to provide disease risk forecasts and demonstrations of MBFM. Growers using MBFM will be supported by information on disease risk on the web and on a toll-free telephone line during the spring. For maximum effectiveness, growers will need to measure plant development, weather conditions and track mummy berries that occur in their fields. Participating growers will be surveyed pre and post-workshops and annual meetings over 2 years to determine their use of pesticides and adoption of MBFM. Presentation materials, a guide to the development stages of the fungus and plants, and updates of existing wild blueberry fact sheets 217 and 219, and new factsheets will be developed to explain the model and how to use it effectively. These will be available on the web and in print. We will send surveys to over 770 growers and stakeholders on the wild Blueberry Newsletter mailing list and get input directly from the Wild Blueberry advisory committee and growers in NH and MA. Research: R1: The interactive effects of weed pressure, fertility and fungicide treatment on severity of mummy berry blight on lowbush blueberries will be determined in a field experiment at 2 sites. A split-plot design with 8 blocks with compare levels of N and P fertilizer, weed control and fungicide control of mummy berry disease. Weed cover will be rated in 2009 and plant samples processed to measure nutrients and fertility. In 2010, insects, weeds, mummy berry disease and yield will be measured. Analysis of covariance (split-plot design) will be performed on the main effects of fungicide and the nested crossed effects of fertilizer and weed control. Contrasts among selected treatment combination will be determined by the presence of the interaction of effects and tested. R2: 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 a replicated complete randomized-block design with 8 blocks. Treatments will include an untreated check, the current fungicide, propiconazole, and low risk fungicides and organic materials applied at their recommended rate. In June, the incidence and severity of mummy berry blight will be measured. In August, the incidence of stems with mummy berries and number of mummy berries per stem will be measured per plot. Yield will be estimated by harvesting a center strip in each plot. Analysis of variance will be used to determine the effectiveness of the treatments on mummy berry disease control and yield.