Effects of Pruning Method on the Incidence of Mummy Berry and Other Lowbush Blueberry Diseases

A shift from biennial burning to mowing as the pruning technique for lowbush blueberry (Vaccinium angustifolium) resulted in a 90-fold increase in mummy berry disease (Monilinia vaccinii-corymbosi) over six crop cycles (12 yr), relative to the disease levels present under burning. After light burning was resumed in a previously mowed field, relative disease incidence was reduced twofold to threefold in each of the two following crop cycles. Two minor diseases of lowbush blueberry, red leaf (Exobasidium vaccinii) and powdery mildew (Microsphaera penicillata var. vaccinii), were not decreased by burning. A return to burning will reduce disease inoculum but is not likely to produce immediate control of mummy berry disease