What insect (larvae?) is eating leaf (fronds) on my balled cypress?

Question: This spring leaf frond development on balled cypress is substantially less advanced and very small dark brown to black insect larvae shell appear to be pulling individual fronds together and forming a sack or possibly a cocoon.  There is also a very small white insects or sack on other branches without a dark brown to black larvae shell attached.  See three photos attached. What is the insect and how can I eliminate them?

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 15, 2023, 12:48 PM EDT
response: Unfortunately we can't identify the insect pictured, though it might be a moth larva (caterpillar) or sawfly larva. It's not quite in focus, plus being dark-bodied makes it hard to see any detail in this lighting. Are the insects doing notable damage to the tree? We don't see any foliage damage in the images, though not all insect larvae pupate (form a cocoon in this case) immediately adjacent to their feeding spot.  How large is the plant currently? If mature, this is an issue that likely is causing it no harm and no treatments are needed since the tree won't be stressed. If it's young or very small (a bonsai, perhaps?) then we can evaluate what to do next if you can share images of its overall canopy and share close-ups of damaged portions of the branches so we can see what kind of damage is being done. Some insect species only have one generation per year so once their larvae are done feeding and spin a cocoon (as appears to be the case here) there won't be any further damage to the plant for that year.  Baldcypress appreciate even soil moisture and the drought we experienced (well, it's not quite over yet, but it's better) to date so far this year might be impacting how readily moisture-sensitive trees expand their new foliage. Perhaps a cause of decline unrelated to these insects caused it to not produce the normal amount of leaf buds last year for this spring's growth. Otherwise, we would suspect damage to the trunk or roots as a primary cause of canopy thinning, or exposure to certain herbicide ingredients (was a weed killer product used on any nearby lawn or garden beds?).  Miri

responder: The Question Asker Replied May 15, 2023, 2:50 PM EDT
response: Miri, thanks for your very prompt and thoughtful reply and sorry for my lack of context and background.  My inspection of the affected bald cypress resulted after comparing the new leafs development to an older (about 9 years older) nearby BC on which the spring time new leaf growth is substantially longer, more robust and developed.  The “impacted” tree is about 10 -12 feet tall with a  2-3 inch diameter and planted (by Tree Montgomery Program) 2 years ago in winter.  It has more full sun exposure than its older companion so assumed lesser annual rain in recent years and this spring  might be a contributing factor.  It benefits from water flowing down from slightly higher but distant roof down spout.  Surrounding soil for both BCs of old pasture land dominated by clay and shale rock fragments.  Both BCs display evidence the same assumed insect presence but I didn’t notice it on the older more developed tree because the leaf development is so rebuts.  Photos provided were the best I could produce.  In retrospect, I really didn’t see evidence of chewing damage to the leaves just the presence of the assumed insect and the leaves being pulled together as if forming a protective space like a cocoon.  I will continue to monitor both tree for observed  problems to see they continue or change,

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 16, 2023, 9:57 AM EDT
response: Ok, thank you for the added information. It's probably not a pest of concern since Baldcypress have very few serious pests or diseases in our area, and we don't recognize the insect you'd pictured as one that commonly is found on these trees as a problem pest. If the one tree's leaf growth appears to be stunted or otherwise unthrifty, perhaps something in its growing conditions or a girdling root (if planted too deeply, for instance) is impacting its vigor instead.  Miri