ddhlakebound
Addicted to ArboristSite
I visited a site today to take a look at a Red Oak in distress. It's root flare was buried an unknown number of years ago (more than 6) with 12"-14" of soil out to 6'-8' radius from the trunk. It's foliage was somewhat sparse, but that wasn't the only problem.
The tree had been attacked by what appeared to me to be twig girdlers laying their eggs. No insects were to be found, only the damage they did to 20-30% of the new growth on the tree. Many 8"ish new growth leaf clusters were dangling straight down, barely hanging on, and already brown and dry. They were severed at the base of this years growth, about 1/8" beyond the woody twig of last years growth.
The way I understand these insects, the larva will grow and eat through the summer, and at some point consume all the woody material leaving only bark to hold the branch, and in late summer/early fall the branch will fall. Then the larva winters in the branch on the ground, and emerges in the spring to continue the cycle.
Is this correct? (Assuming I've properly identified the pest)
Can the larva survive if the pruned branch hangs up in the tree? Or do all the insect pruned branches need to be cleanup up and disposed of, on the ground and airborne?
There were a few other trees showing signs of distress from having dirt piled on the root flare, one White Oak in particular, but no other trees had been attacked by the twig pruners the way the one Red Oak had been.
Another ?.....Where are the adult insects now? Do they expire shortly after laying their eggs?
I only had my cell phone camera onsite, attached are a pick of the trunk/grade change, and a pic of a dead end hanging from the twig.
I did bring a small sample home, to get a bit better pic of a damaged sample still dangling from the green twig.
I disected the twig, shaving small layers off with each slice, looking for a small larva, but either the egg hadn't hatched yet, or I somehow missed the evidence of the egg/larva being there. There was no damage to the interior of the twig.
Should the eggs be hatched by now? If it wasn't, would the egg be visible to the naked eye inside the twig?
I'll be recommending an immeadiate root flare excavation, and a fresh layer of organic mulch, and cleanup/destruction of all the insect pruned branches when they fall, to break the cycle of destruction. Is there anything else I should do?
The tree had been attacked by what appeared to me to be twig girdlers laying their eggs. No insects were to be found, only the damage they did to 20-30% of the new growth on the tree. Many 8"ish new growth leaf clusters were dangling straight down, barely hanging on, and already brown and dry. They were severed at the base of this years growth, about 1/8" beyond the woody twig of last years growth.
The way I understand these insects, the larva will grow and eat through the summer, and at some point consume all the woody material leaving only bark to hold the branch, and in late summer/early fall the branch will fall. Then the larva winters in the branch on the ground, and emerges in the spring to continue the cycle.
Is this correct? (Assuming I've properly identified the pest)
Can the larva survive if the pruned branch hangs up in the tree? Or do all the insect pruned branches need to be cleanup up and disposed of, on the ground and airborne?
There were a few other trees showing signs of distress from having dirt piled on the root flare, one White Oak in particular, but no other trees had been attacked by the twig pruners the way the one Red Oak had been.
Another ?.....Where are the adult insects now? Do they expire shortly after laying their eggs?
I only had my cell phone camera onsite, attached are a pick of the trunk/grade change, and a pic of a dead end hanging from the twig.
I did bring a small sample home, to get a bit better pic of a damaged sample still dangling from the green twig.
I disected the twig, shaving small layers off with each slice, looking for a small larva, but either the egg hadn't hatched yet, or I somehow missed the evidence of the egg/larva being there. There was no damage to the interior of the twig.
Should the eggs be hatched by now? If it wasn't, would the egg be visible to the naked eye inside the twig?
I'll be recommending an immeadiate root flare excavation, and a fresh layer of organic mulch, and cleanup/destruction of all the insect pruned branches when they fall, to break the cycle of destruction. Is there anything else I should do?
