This is a 7 foot lily cane that I noticed had some white stuff on the leaves and on closer inspection find a hole. Its about a foot up the cane. We have lots of Carpenter Bees but I've never seen them in living plants.

It's some kind of borer, Papaipema nebris is one that is said to attack Lilium (it's a moth caterpillar). If you're seeing the white stuff (frass) increase then it's likely still in the stem feeding and I expect the top of the lily may wilt. Not sure but that may not be the only borer that can attack lilies. We'd need to see the culprit to ID it.

It isn't frass. It's some of the pith pushed out during excavation it think. I may just go sit there for awhile and see. It's cool and rainy for a few days though. That moth's range is Texas and to the east from what I see. I hope it isn't. I'll have to closely check the other stalk. So far the tops look OK. It's the far one here.

Just found this googling lily pith borers. [url] http://garden.org/nga/searchqa... [/url]

Papaipema nebris is a long way east from California..

http://mothphotographersgroup....

I found one the same but there's no scientific name.

http://www.petaltalk-jean.com/...

Lily weevil - Agasphaerops nigra is in the north of California ..

http://www.herbs2000.com/flowe...

https://www.google.co.uk/searc...

The same damage in Oregon:

https://ask.extension.org/ques...

Agasphaerops nigra in California ..

http://clade.ansp.org/entomolo...

https://books.google.co.uk/boo...

Papaipema nigris was an omission on my part since I failed to check Leslieray's location, although in my defence I'd add that I did say it may not be the only borer to attack Lilium I had seen an article that suggested P. nigris had been noted in British Columbia but also that that might have been a mis-identification.

Janet, I haven't checked any other references for it but the second link above for Agasphaerops nigra indicates it attacks the bulbs and underground stems whereas this seems to be higher up. Frass was white though on the extension.org page that incriminated it, although it could be for some kind of Noctuid moth also so that probably doesn't help.

I sent this photo of to Baldo Villegas a former UCD entomologist and Rosarian. I thought he might be interested because this plant is in the midst of the Historic Rose Garden. I'll have a look at both canes top to bottom tomorrow. Agasphaerops nigra adults emerge in March and April and feed on leaves. I see no sign of that. The damage in Oregon does look exactly the same. The white in my photos is pith.

Yes I read about Agasphaerops nigra attacking bulbs and underground stems Sue, but the person answering on extension.org thought it could be Agasphaerops nigra. I guess they tunnel up the stem, or down it, need to do more research on it.

I see you've done more research on it Leslieray.

The white may be pith, which suggests something has bored it's way in or out of the stem. It reminds me of woodworm which push chewed up wood out of the hole which happens I think when they escape but I need to refresh my memory on that.

Quoting from Janet's reference, "The white substance you see on the leaves beneath the hole is frass, or insect excrement". My understanding was that the poop often reflected the diet, so if it is munching its way in through the pith then the "end result" will potentially be white. Either way it is the sign of a borer of some kind.

So you're thinking it may be an exit hole, Janet? I thought that usually there was only frass/sawdust/whatever below the entry holes because with the exit holes the debris would be left inside the stem. Need to read up on that again too.

The text on google books states: "the larvae borrow into the lily stem and bulb".

https://books.google.co.uk/boo...

Have you looked carefully to see if the leaves have been eaten Leslieray?

The stems show brown marks like a sawfly would make when cutting in eggs. There is a brown patch on the leaf on the right stem, could that be from a weevil? I'm not sure how they feed!



I had come across a sawfly which attacks "other arborescent plant families" in California.

Larvae in the tribe Cephini are internal borers in
stems of Gramineae, while those in the tribe Hartigiini
bore in the twigs of Rosaceae or other arborescent
plant families.

http://essig.berkeley.edu/docu...

Yes Sue, I think as the adult beetle chews it's way out it pushes the debris out but it doesn't seem possible to do that until the exit hole is complete. Maybe the debris gets dragged out with the beetle? I have seen the holes with small piles of dust pushed out, and you don't see holes until the beetle has eaten it's way out.

http://www.rentokil.co.uk/blog...

NATURE OF INJURY

Both adults and larvae feed on lily plants and the injury they cause may be grouped under three types, as follows : ( 1 ) The adults eat shallow, crescent-shaped notches on the edges of the foliage (fig. i) — a feeding only slightly detrimental to the plants hut furnishing an indication of the presence of the insects; (2) the larvae feed in the under-ground parts of the stems and (3) in the bulbs, both types of injury being very serious in their effect. Some small larvae apparently feed on the surfaces of the stems without making any effort to burrow within (fig. 2). These, while still small, either reach the bulbs or succumb to natural influences. Others very distinctly eat their way through the outer stem wall, at or below the soil surface, or at times even a little above, and tunnel up and down within the pithy interior (fig. 3). The
stem often is completely severed by such feeding, and the bulb, failing to receive plant food which is necessary for development, practically
ceases growth.

The larvae frequently complete their development in their burrows, which are more or less filled with frass (fig. 4). The stem tissue seems to be preferred by the larvae to bulb tissue. In older plants, with correspondingly large stems, more larvae have been found attacking stems than bulbs. The more extensive injury noted on bulbs of smaller and younger plants is possibly clue to the failure of the smaller stems to furnish sufficient food for the larvae.

The brown marks on the stems could be from small larvae?! Size of the stem seems to determine whether they feed more on the stem or the bulb, as this is a large stem then it would provide plenty of food.

Look for shallow, crescent-shaped notches on the edges of the foliage.

https://archive.org/stream/lil...

I found this in an extension.org article about powderpost beetles in wood(not suggesting that's what this is):

"Active infestations are characterized by frass streaming from or accumulating around the exit hole on the wood’s surface. Adult powderpost beetles are rarely seen. Exit holes with no frass present is evidence of a prior infestation, but not necessarily one that is still active. "

I did read somewhere else on borers in plants that some may push debris/frass out of the hole to keep it from accumulating in the hollow where they're still feeding.

I would think if the culprit was long gone the debris/frass would have been blown or washed away. Perhaps, Leslieray, you could clear away the white stuff and see if more accumulates again, that might indicate whether it is still in there.

I found the illustrations on a pdf. On page 17 an illustration of leaf mines made by newly hatched larvae. Page 3 shows the elongated scars on the stem from immature larvae.

https://ia601704.us.archive.or...

A thought, if there's no chewed leaves that doesn't mean there was no beetle. It might have been taken for food once it emerged!

Good find on the article, Janet. It does seem to fit, there appears to be mining injury on the leaves and stems as described in the article.

It's rained since the photos and more rain tonight so it may be clean of debris. The damage on the canes does look like grazing. I'll bring a hand lens and have a look maybe take some micros if I can manage it. Anything is better that the weeding and rose deadheading when it's wet. One question though as I mentioned before that these adults emerge in April and May after pupation. Maybe earlier here and then mating and egg laying and hatching and then the small larvae eat the exterior cane in this instance and make there way down the cane and into the bulb or through the cane at ground level so there should be larvae of holes at ground level maybe? I'll give both canes a thorough photo. Easier to see after it's blown up. I find a bug in every photo I take it seems. Thanks for all the help.

It is possible that the grazing on the stems is from a new batch of eggs. I didn't read all the article so don't know how long it would take for eggs to hatch but I doubt it would take long, the lily won't have been in growth over winter so it has to be a quick process.

If the larvae make their way into the stem when they are very small, which they would do, then you might not easily find their entry holes which could be further up the stem. It's a large stem so with plentiful food they might not go to the bulb, they do that when the stem is small and doesn't provide sufficient nutrients.

Once you start to look seriously, you will find a myriad of bugs you never knew existed. It's a real eye opener, your recognition skills when looking at plants develop into spotting tiny insects where once you wouldn't have seen them.

Sue, we have to thank all those people who put billions of old documents on the internet, there's teams of people who do this for free. 20 years ago there was very little on the internet, it was still quite new.

Yes, I remember way back when the internet was text only and there was nothing like the availability of information there is now. Although now one has to do more sifting through articles that are trying to sell something

Figure 18 on the PDF is a chart that shows the timing of when the life stages occur - there's apparently a long period of "inactivity" which extends the life cycle to two years, so you can have two alternating broods.

sooby said:Yes, I remember way back when the internet was text only and there was nothing like the availability of information there is now. Although now one has to do more sifting through articles that are trying to sell something

Figure 18 on the PDF is a chart that shows the timing of when the life stages occur - there's apparently a long period of "inactivity" which extends the life cycle to two years, so you can have two alternating broods.

I shouldn't have been lazy, the document in book form isn't very long.

For extended breeding the larvae must then reside in the stem and bulb underground. Nature is marvellous, making their survival chances more likely!

I just had a quick read, on page 20 it says egg deposition doesn't begin until the end of April or early May. The larvae remain in the larval form for the first winter, then as adults in cells in the soil formed by the larvae. That suggests, as the hole is new, the larvae has gone to ground to make it's cell? If it resided in the bulb or underground stem for last winter, it could have then made it's way up the stem to feed then ate it's way out?