Efficacy of Organically Acceptable Materials for Control of Mummy Berry Disease on Lowbush Blueberries in Maine

Abstract

The efficacy of biological controls and application of mulch for control of the blight stage of mummy berry disease was examined in different lowbush blueberry fields in Maine over 5 years. Biological controls tested included compost teas and commercial products containing Trichoderma harzianum, Bacillus pumilus, B. subtilis, Streptomyces lydicus, and plant extracts of neem, garlic, citrus, and giant knotweed. Treatment with compost teas did not affect numbers of fungal and bacterial colony-forming units on leaves compared to controls. Early application of peat mulch before leaf bud break was partially effective at controlling disease in the field. In 2010, extracts of citrus and giant knotweed and a B. subtilis commercial product were effective at controlling disease in at least one of two fields. The other biological controls did not significantly decrease disease incidence compared to untreated controls.