Creepy Crawlies

 

If you have boxwoods, you probably know that now is the perfect time to prune them, during their dormancy. While I was out pruning yesterday I also ran into these fauna: boxwood leaf miners (Monarthropalpus flavus).

I have been learning about them over the last few years but am reading up again as I do most winters. There is always something to learn.   One source says that the Boxwood leaf miner is most common on American boxwoods, not seen as much on English or Korean boxwoods.

So what do we know about them? The boxwood leaf miners emerge as adults in late April to early May depending on the temperatures. The adult is a flying insect which briefly lives to deposit eggs in the newest flush of spring leaves. Then the larva grows in the leaf until next spring.

These creatures were on a series of dwarf boxwoods in a south Nashville garden. There are large boxwoods on the property, probably English, that showed no signs of leaf miners.

 

Here, note the front and back side of the leaves;  both sides look blistered. The affected leaves are only at the outer several inches of the twigs. Inside the blisters are larvae which are growing between the leaf’s front and back surface. If you carefully tear open the leaf, you may find a larva. Or two.  Maybe wiggling. Tiny yellow bits of life.These larvae will pupate this spring. And start the cycle again.

How bad is this? Depending on who you ask, not so bad, just an aesthetic buzz-kill.  Or they can weaken and kill your plant over time. I cannot give specific treatment advice,  but there’s plenty of research to be found on chemical controls. I have also heard about a wasp predator, either the Diglyphus isaea or possibly Dacnusa,  which might be worth learning more about.

Happy pruning!