Boxwood Leaf Miner: "Dr. Z's" Tip of the Week

We have had many customers bring in Boxwood Leaf Miner this season!    It is a major pest of boxwood.
The damage is easy to spot.  The leaves are puckered or blistered.  The insect has eaten all the plant tissue between the two leaf surfaces.  The leaves will then turn yellow and drop prematurely off the boxwood.  Sections of the plant will die off, eventually leading to the death of the whole plant.
The maggots (pupae) that do the mining come from an orange, gnat like fly.  These flies hover over the boxwood and lay their eggs onto the leaf surface.  These in turn burrow into the leaf and begin mining.  It is very hard to kill once it has entered the leaf.
The objective of our intervention with sprays is to kill those eggs before they burrow into the leaf. Several treatments may be necessary since the flies are around for most of the summer.  A good organic spray to use would be Neem Oil.
If Boxwood Leaf Miner is a reoccurring problem each year, you may want to consider applying a chemical systemic, such as Merit, to the soil in early spring to provide protection for the whole season.    Please stop in to see me about your particular garden situation!