This week, we looked 2-year-old loblolly showing dieback in the tips of branches. This turned out to be damage from tip moths, Rhycacionia genera. There are different species. Loblolly’s are susceptible to tip moths, especially young, less than 5 -6 feet tall. The damage is similar: the tips of terminals and laterals are killed as result of larval boring into base of the needles or buds, and then into the shoot itself. They can also kill small trees.
Eggs are laid on the base of needles. When the eggs hatch, larvae bore into the needle sheaths and mine needles near their base. By midwummer, larvae move to buds and burrow in them. They stop feeding in August. They overwinter in the wound area. On the terminal of branches, we observed resin-coated webs, frass from worms, brown needles, and where worms were still present, you can see the tunnel in the branch. We also found a few caterpillars inside the stem. This is something we probably need to think about treating, though we are past effective treatments now. Here is a table from the book “Insects That Feed On Shrubs & Trees” showing species and hosts.
When it comes to treating, UGA Extension Forestry Specialist Dr. David Moorhead has a detailed guide to spray control. See the weather station locations in Table 4 to choose a site closest to your site for the spray date times. There are numerous insecticides in the 2016 UGA Pest Control Handbook that are effective for control. These can be applied by fixed wing crop dusters or by ground rigs.
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