Wednesday, January 25, 2023

2023 Insect Predictions

I start this blog with a fair warning that is incredibly hard to predict which insects will emerge or be an issue from season to season.  But I'm pretty confident, based on the weather last year, I can make a fair  prediction.... borers in trees will be seen in 2023!

It may be hard right now to remember the intense heat we experienced for months this summer, but we are all well aware of the continued lack of rain.  Heat and drought are stresses on trees that we often overlook. We tend to baby our smaller plants, but ignore our larger ones.  I often assume mine get what they need - they've been there forever, after all!

Trees DO need water.  Tree ARE damaged by heat.  The damage and stress these trees experienced, likely caused them to be attractive to boring insects.  Boring insects are OPPORTUNISTIC.  I say that because we always love to blame insects for the reason a plant, tree, etc. is failing.  Boring insects take advantage of a good situation, detecting a wound or that the tree cannot fight them off naturally.  They lay their eggs in a crevice or on the bark of the tree and that baby beetle (grub) starts to burrow through the tree.  When they've fed enough, they pupate.  This egg to pupa stage can last up to a year or more!  The resulting adult that emerges, leaves holes it's chewed to get out of the wood.  These holes are noticed by tree owners and we assume the poor tree is weak due to the borers.

Exit holes from Roundheaded Borer in tree.

Remember!  When you see the boring beetles exiting, they've already done the damage!  They were attracted to a tree a year prior, when it exhibited signs of stress.  You can't do anything now... this is unfortunately a sign of what you didn't do.

Red Oak Borers - Round headed Borers

Metallic Wood Boring Beetle - Flatheaded Borer
Hanna Royals, Museum Collections, USDA APHIS PPQ

The best course of action is to care for those trees.  Water them, fertilize them when you should, don't hit them with the mower or weed wacker.  Prune them properly, don't choke them with soil or mulch, don't compact the soil.  Overall, just treat them like you do your flowering plants... they need your attention too! 

The other thing to consider is the age of the tree.  Is is at the end of it's life anyway?  Trees don't live forever and boring beetles detect this and are attracted to them.  They aren't killing the tree, they are putting it out of it's misery.

Moral of the story- if you start to see boring damage this spring and summer (holes from emergence), don't panic!  There's no need to treat - the beetles are leaving!  If your other trees are healthy, you don't need to worry!

There are some exceptions to the rule that boring beetles are secondary and opportunistic.  Learn more about the invasive and highly destructive Emerald Ash Borer.

Click here for more information on wood boring beetles.