Larvae Raining From Pine Trees

One afternoon last week I came home from work, and when I got out of the car I found it had already accumulated a large number of wriggling white larvae, which were dropping onto it from the white pine tree overhead.  This exact thing had happened on May 24 last year, and I was expecting it this time around because I knew it would coincide with the week that I’m sneezing from all the pine pollen filling the air.  The ~4 mm larvae appear pretty much featureless to the naked eye, but under magnification you can see that they have six legs and a round head with two eye spots and a pair of short antennae.



Last year I dropped a number of them into a jar of soil to try and raise them, and they immediately burrowed down into it and disappeared.  Nothing has emerged, but I’m pretty sure they are sawflies in the genus Xyela (Xyelidae).  I first became aware of their life cycle early last April when I started seeing the adults in and around the house.  I posted this photo (taken April 6) on BugGuide…


…and when it was identified to genus I read up and learned that the larvae develop in the male (pollen-producing) cones of pines.  After feeding for two or three weeks, they drop to the ground, burrow down, and wait there through the winter before pupating.  Adults emerge in early spring, mate, and females lay eggs in the developing cones.  On April 17 this year, I took the photo below of an adult (4 mm long, like the larvae) showing off her ovipositor below the very same tree from which I’ve seen the larvae raining down.


Added 9/29/2013: Sawfly specialist Dave Smith has just confirmed that these are Xyela larvae.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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35 Responses to Larvae Raining From Pine Trees

  1. Cindy says:

    Love your book – love this blog – maybe even more! Great to see pictures of the actual stages. Thank you so much! — Cindy

  2. Scott says:

    I have the same thing. Over several years I have noticed the tree is less healthy. Can I do anything to protect the tree?
    I’m afraid they will kill the tree.

    PS. Nice pics

  3. Seth Carter says:

    I was outside today in NH (6/9/14) speaking with some friends and as a breeze picked up we began getting hit with what we thought were little seeds. When I looked at my crossed my arms I noticed 15-20 of these little buggers had accumulated. There are many white pines in the business park where we were standing and the “seeds” were coming from their direction. Thanks for the information and photos, they were clearly sawfly larvae.

  4. Anonymous says:

    We live in north central MA and have a great (new this year) patio that is unusable due to the larvae that are pelting. Will they stop falling when the pine pollen stops?

  5. Hi Charley! Glad I’ve never encountered these as I harvest the male pollen cones to eat as well as their pollen. (Guess I may be getting some extra protein without even knowing it!) Are they so super tiny that I could be missing them?

    • Hi Blanche! They’re ~4 mm long when full-grown, so you would probably notice them if they were there. I’m sure they’re fine to eat–just extra protein, as you said!

  6. Pingback: Four Years of Bug Tracking | BugTracks

  7. Anonymous says:

    I just saw these in New Hampshire. I was fly fishing a trout pond on 6/14/2016 on windy day. They’d blow off the pines into the water and the trout were having a feeding frenzy! Most were very tiny and thin. Tied on the smallest white fly I could find and bang, bang, bang! Thanks for posting this!

  8. Haf Gaemer says:

    Hi, I have been listening to these larvae drop from the trees every night for the last week or better. I have a hammock that I sleep in sometimes and sometime after midnight these things will begin falling from the trees until around dawn at which point they stop dropping. I can’t sleep in my hammock as it fills up every night with these little larvae and It’s hard to sleep when your being pelted with small maggots. I figured they would be done spawning these little buggers by now, but not yet.. Do you know how long they do this?

  9. Kathy says:

    I noticed today that there are lots of tiny white worms falling off an Ash tree (similar to maggots) but very easy to squish, which tells me that they are not maggots. I squished a few and it is all white, inside and out.
    Never seen something like it! I live in town in southern Manitoba, and the tree is next to my house. Any suggestions what to do about that??
    Or what they may be???

    • I would have to see them to offer an informed opinion, but there are a few species of midges that form galls on ash leaves, whose larvae drop to the ground to pupate. The larvae are white in both species that come to mind–Dasineura pellex and Dasineura tumidosae. Neither would have any effect on the health of the tree, and there is no reason to do anything about them.

  10. Lora Arthur says:

    Can these larvae be harmfull? I was sanding furniture outside for a couple of days and broke out in small itchy hives. After investigating, I noticed what I thought was pollen was actually very teeny worm-like larvae. Could this have caused the hive like bug bites?

  11. kunal says:

    How to kill them ???

  12. StephF says:

    Thank you for your article. We live in Central Wisconsin, and had put our swimming pool up for the day right under our favorite white pine. Our fun was cut short by hundreds of tiny white larvae raining down onto us. I’ve been looking all over the internet to figure out what they are, and if I should be worried about my tree. Glad they are harmless, and glad to have a name to put on the phenomenon!

  13. CA says:

    We had so many of these and as you broom them away they keep falling down. They stopped falling however, they have settled onto surfaces and are hard and difficult to remove. They are all over our furniture, cars, and decking. Do you know how to remove them from surfaces? Also, was it the unusual high temperatures in September that caused this or is this a yearly thing that I may have missed in the past?

    • It seems unlikely that the larvae you’re seeing are these sawflies, given the season. I wouldn’t think the pollen cones would be far enough along for the larvae to develop–not to mention that adults wouldn’t be laying eggs in the cones until next spring.

  14. Anna-Maria says:

    October 31, 2018. I went out this morning to discover what looked like bright orange accumulations of pollen in depressions in my grassless horse paddock. Upon closer inspection I saw the things were bigger than pollen and some were leaping in the air like popcorn. They could leap about 3” high. They looked like minuscule, hairless caterpillars, ranging in colour from bright yellow to bright orange, with some of them being bi-coloured. They are so tiny it is difficult to see any features but I see no evidence of eyes or any other markings. They were only in places under Douglas fir trees. Not knowing for sure if they were falling from the trees or coming up from the ground, I put a black tarp under a fir and it didn’t take long for several to drop onto it. They were everywhere on my forested property, not just in the horse paddock…just harder to see in the grassier areas as opposed to just damp dirt. We had a heavy rain last night and I wonder if the rain caused them to fall in such numbers as I have lived here for 17 years and never seen anything like it. They sound like they could be sawfly larvae but they are the wrong colour and are appearing at the wrong time of year. I live in south central British Columbia at an elevation of 3,500ft. We’ve had several hard frosts. I have tried to find out what they are and if I should be worried about some kind of later outbreak when they mature but have found nothing just like them. I have pictures but did not see how to post them here. Please help. Thank you.

    • Tiny, orange, featureless larvae sound like gall midges to me. If you post the photos to the ID Request page on I can take a look. But assuming that’s what they are, I just checked my gall midge book, and orange larvae dropping from Douglas-firs in the fall could be any of several species that develop in the cones. The species that feed on needles and twigs, which are the only ones that could conceivably damage the trees, all either have white/yellow larvae or don’t drop to the ground. So as with the sawfly larvae, these orange larvae are nothing to worry about.

  15. greg says:

    Great information! I’m in Colorado near the foothils, june 12th. When I woke up this morning I saw probably 100 of the larvea on a tarp on the ground. Right underneath a pine tree covered with pollen pods.
    You satusfied my curiosity.

    • Isn’t the internet great? I love that a post I wrote six years ago is so easy to find and helps people solve the mystery of what’s dropping from their pine trees en masse in the spring.

  16. frank says:

    I cut down a small white pine this year cut the pieces up for campfire. Still in pile I started hearing crunching. So I split a couple pieces open and found the same larvae in your pictures boy do they make a lot of noise.

  17. Janette says:

    How long do these tiny white worms last, my backyard neighbour has a long needle green tree and it’s branches are overlapping into our backyard and these tiny critters are falling right into my in ground pool, which makes it “uncomfortable “ for swimming knowing they are in the pool! My skimmer basket is loaded with them and the deep end at the bottom is also loaded with them , in constantly scooping them out from the bottom and those that are floating on top! It’s no enjoyment swimming with these things !

  18. Louvenia Azzan says:

    This was very helpful in identifying these worms we saw in our pine spruce candle. Thank you.

  19. Linda Hendrickx says:

    How long do they continue to fall? I’m not going outside until they stop.

  20. Leslie Page says:

    I have a small tiny larva or maggot like worm falling on me when i lay in my is so small it very hard to see. I did take pictures.. i can email them to you. I really love you article, it is very informative..will they borrow into my skin, eyes..

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