Tree problems · Insect
Sawflies: signs and what to do
Sawflies is an insect pest, often seen on pines, spruces, flowering dogwood. Look for: groups of caterpillar-like larvae feeding together on needles or leaves.
General information, not a diagnosis. A certified arborist or your county extension office can confirm.
- Insect
- Pines
- Spruces
- Flowering dogwood
- Oaks
- Other trees, depending on the sawfly
Signs to look for
Tick what you see. More ticks make it more likely, but only an on-site look can confirm.
0 of 5 signs ticked. Ticks stay in this browser only.
Season
Timing depends on the species. One extension source says red-headed pine sawfly feeding peaks in May and June, and yellow-headed spruce sawfly larvae feed from mid-June to mid-July. Some species have more than one generation a year.
How it spreads
Adult sawflies fly to host trees and cut slits in needles or leaves with a saw-like egg-laying tool to lay eggs. Larvae then feed, often in groups, before dropping to the ground to pupate.
Where it is found
Sawflies of many kinds live across the United States. Check your state official map and your county extension office for the species near you; ranges change.
Official sources
What to do
- 1
Look closely at the larvae. Take clear photos and note the tree species.
- 2
Check the tree often in the weeks when feeding is likely, because groups of larvae can strip branches fast.
- 3
For a few larvae, extension sources suggest removing them by hand or pruning off the affected branch tips.
- 4
Ask your extension office what to use if numbers are high. Caterpillar products may not work on sawflies, and the right choice depends on the species.
- 5
Water the tree in dry weather to help it recover.
- 6
Take photos and ask a certified arborist if a tree is losing most of its needles.
Safety first: do not climb, do not cut near power lines and do not use a chainsaw on storm-loaded wood. Call the utility for downed lines and 911 if anyone is in danger.
Prevention
Check pines and spruces each spring and early summer. Keep trees healthy with watering and mulch. Catching larvae while they are young and in small groups makes control much easier.
When to call a pro
Call a certified arborist if feeding is heavy, if a young or valuable conifer is losing many needles, or if the tree is too tall to check safely. Large trees need trained, insured crews and proper equipment.
Not sure who to call? Read how to hire a tree service or check is my tree dangerous?
Trees it affects
Usually seen on: Pines, Spruces, Flowering dogwood, Oaks, Other trees, depending on the sawfly.
- Eastern White Pine
- Red Pine
- Jack Pine
- Pitch Pine
- Norway Spruce
- White Spruce
- Flowering Dogwood
- Pin Oak
See all species in our tree library, or pick a tougher tree with the tree picker.
For tree companies
How to explain sawflies to a customer
Teach owners to tell sawfly larvae from caterpillars, because the best product can differ. Be honest that severe feeding on conifers can kill a tree, but most deciduous damage is cosmetic. Offer clear steps: confirm, remove by hand if few, treat if many.
Send this page to the customer after your visit so they can read the signs in plain words. See also selling plant health care and the job photo checklist.
Questions
What are sawflies?
They are related to wasps. The young stages look like caterpillars and feed on leaves or needles, often in groups.
How can I tell sawflies from caterpillars?
Sawfly larvae have one eye on each side of the head and no tiny hooks on their stubby legs. Caterpillars usually have six eyes on each side and hooks. Ask an expert if unsure.
Will sawflies kill my tree?
Severe feeding can kill conifers. On many other trees the damage is mostly to looks. Ask your extension office about your tree.
Is it too late once I see them?
Not always. Young larvae are easier to control. Check often and act quickly.
Will the usual caterpillar spray work?
Not always. Some caterpillar products do not work on sawflies. Ask your extension office for the right product for your species.
Will they come back next year?
Possibly. Larvae drop to the ground to pupate, and adults return the next season. Check your trees at the same time each year.
Can Lirevon diagnose sawflies on my tree?
No. Lirevon is a remote marketing team for tree service companies and does not do tree work. This page is general information, not a diagnosis. A certified arborist or your county extension office can confirm what is wrong with your tree.
How do I find a good local pro for this?
Search Google Maps for certified arborists or tree services near you, read their reviews and ask for proof of insurance. Get two or three written quotes. Our guide on how to hire a tree service lists the questions to ask.
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