Peeled open a late-germinator from ‘New Dawn’ OP and found this white grub instead of an embryo…
What in the PNW do we think it is?
I threw out the rest of the baggie of seeds to be safe.
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When I was in Chicago last fall I had the opportunity to liberate some OP hips. Some of them had these same looking pests inside the achenes. Most failed but a few managed to sprout and grow while the grub was still eating them. Took me a few days to figure out what was going on, but I managed to save a few where they went for the cotelydons instead of the radicle.
I did the same as you and ditched the seeds since I couldn’t identify the pest. Wasn’t worth the uncertainty.
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I like to claim l found the same problem … on R penndulina seeds a couple years ago.
Except not me. Some exceptional observational skills of a sharp expert in Canadain heritage roses spotted the same problem on a photo of my seeds.
Little holes drilled into small seeds. Dump the bag and sure enough dead white grubs with wriggle or two left can out of bag. Cold doesn’t terminate everything on the prairies.
If they see this note they might give you a suggestion what the wriggle rats were- l don’t recall the tech name.
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I believe that, in this case, it is a species from the genus Rhagoletis in the family of fruit flies, Tephritidae. I see larvae like this in my rose hips almost every year, and in 2019 I even asked an entomologist I know about it. He confirmed my suspicion. However, the species Rhagoletis alternata (Europe) or Rhagoletis basiola (USA, Canda), rose hip flies, do not eat the seeds inside the hip. These usually continue to develop even when infested.
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Crikey that’s a rose defiling monster compared to the little wriggle rat grubs l had that made holes in seeds. Got c if l can find the pictures l took.
From the expert X and AI “
“ megastigamus - a genus of tiny, parasitic wasps (not true flies) within the Chalcidoidea superfamily, often called “seed chalcids” due to their larvae feeding inside plant seeds, particularly conifers and roses”
Could it be the more common larvae of the rose cucurlio?
Always nuking them in my garden when caught in the act of drilling the buds … easy target, bright red here with a wicked looking drill stem - no doubt tip with a diamond studded tri-cone drill bit.
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I’ve never had this kind of infestation before, but your suggestion fits even better! Interesting and fine that the pest has been identified.
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I have had a bunch of these in my hips before. They might affect the germ rates some but I still managed to pop some from those batches.
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Found this old thread (which came up on a google search) and I think we have a match.
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Looks like a match. Yet another introduced species. Multiflora roses are the gift that keeps on giving.
Those little stinkers are sure a pest! I’ve found they tend to like certain roses, having far more in some than others. They will completely eat a seed up, leaving only an empty shell.
I have, however, kept some seeds after discarding partially eaten ones. The seeds seemed fine and even had some germinate. Of course perhaps there is a risk in keeping some? Perhaps separate them in their own bag?
Duane
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Here we go again:
Now a different MOFO, of similar look but larger, is appearing inside newly opened flowers (in this case ‘Mrs. Oakley Fisher’), with eaten stamens and a LOT of frass/“bug poop”. What the Sam Helliot are they and how can I control them? They’re messing with my plans.
Possibly related, I did see small, long-n-skinny, black wasps earlier on the buds of many of my roses, and they seemed to be ovipositing (is that even a word?!?) onto/into them. I consider wasps allies for the most part; must I declare war on certain species, and how?
Please advise,
Dusty.
Do I not see a translucent looking larvae of something curled up inside the anthers? (Rose slug? Sawfly?)
Yup. But it’s not a pest I’m familiar with, have done battle against the rose-slugs in another yard. In my current space, it’s caterpillars of various types, burrowing into blossoms and down into the cane.
I curse and squish them with prejudice! Very satisfying to see their insides burst outside, IMO. #HeHadItComing
This particular pest though seems content enough to curl up within the bud and consume the anthers and stamens. Furthermore, it seems to really be mostly ‘Mrs Oakley Fisher’ that is suffering the brunt of this pestilence. I’m quietly raging, with regular bursts of profanity.
Dusty.
Declaring war on specific species is difficult. Insecticides don’t discriminate between the insects you love and the insects you hate. Since it seems to prefer that one rose maybe you could buy or propagate another to place in a more appealing area as a trap crop? From there I’m sure soapy water or other kinetic measures could prove more effective.
Notable exception being BTK.
But that’s a one off, and not really appropriate to use on something munching INSIDE a closed bud.
I’m pesticide-certified and a big proponent of IPM, so that’s why I do mixed plantings in large containers, and encourage ladybugs, wasps, and other predators with appropriate feed and host plants.
A beautiful, rather large lacewing landed on my hand yesterday, as if to let me know they are here!
It’s nice when a plan works out.
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