Growing season effects on wild blueberry (Vaccinium angustifolium) in Maine and implications for management.

摘要

The growing season in Maine has increased by more than a month over the last 50 years. The advent of warmer temperatures, a longer growing season and more uneven precipitation has increased the weed, insect and disease pressures for wild blueberry (Vaccinium angustifolium) growers. Because wild blueberries are pruned every other year there is an opportunity to use the cultural management practice of spot mowing or burning to control pests such as thrips, tipworm and Valdensinia leaf spot in the non-bearing year. To evaluate the current growth status wild blueberry plants were pruned in the fall and at intervals from April to August in 2004 to 2009 over two growing cycles to see if there was a cumulative effect on potential yield as measured by number of flower buds per stem. There was a progressive decline in buds over the season reaching zero by the end of July or early August. A cumulative decline in flower buds was seen when plants were pruned late in the season in consecutive production cycles. When compared to data from a 1960 study, if May 1 is considered to be 100% buds then the 1960 study had a decline of 60% for June 1 and 100% for July 1 versus this study with a only a 20 and 50% decline for the same dates of pruning indicating that spot pruning may be done later in the year with less of a reduction in wild blueberry yield than was previously reported.