Effects of summer and fall applications of foliar boron on fruit bud winter injury in wild blueberry (Vaccinium angustifolium Ait.)

The effects of single and multiple applications of foliar B to two commercial wild blueberry sites during 1999 to 2001 were determined. The effects on tissue B concentrations and winter injury to developing fruit buds was evaluated. At one site, applications of foliar B in summer or fall or in both seasons increased tissue B levels in the first crop fruit buds, but the increases were not observed 1 yr later in the second crop fruit buds. At the other site, applications of foliar B in both the summer and fall of two successive cropping cycles reduced winter injury compared with untreated controls, indicating that multiple foliar B applications may be required to reduce winter injury to developing buds of wild blueberry.