Development of a cover crop system for management of flatheaded borers in red maple production

Abstract

In woody ornamental production, winter cover crops have been used to successfully reduce flatheaded borer (Chrysobrothris sp; FB) damage to red maple trees(Acer rubrum L.). FB is especially damaging during the first two years following transplant. After tree establishment, attacks decrease, but they may still occur at some level during subsequent production years. The trees in the experiment were assigned to four treatments: cover crop, cover crop + insecticide, bare row and bare row + insecticide (recommended treatment) and replicated four times in a randomized complete block design with 25 trees per block. All treatments were evaluated for FB damage and tree growth for the first two years. The winter cover crop prevented FB damage during years 1 and 2, with results similar to the recommended treatment of systemic imidacloprid. Direct competition for nutrients and water negatively impacted tree growth in the cover crop treatments. During years 3 and 4, trees were further evaluated for growth and additional FB attacks. Tree rows in all previous treatments were maintained similarly, with tree rows kept bare with pre- and post-emergent herbicide.  At the end of year 4, trees in the cover crop treatment showed some growth recovery, however, they remained smaller than trees grown under standard insecticide and herbicide production practices for all four years (24% smaller trunk diameter, 18% shorter). Additional management techniques will be required to mitigate the growth disparities between trees grown with cover crops and standard production methods