Camperdown Leaf Hole Treatment Summer?

Question: I recently purchased about an 8 ft tall Camperdown. The nursery gave me a discount and did not have much info on the leaf damage, so I am trying to do my own research. It seems like leaf miners are the most common issue, but all suggestions say the the tree needs to be treated in spring/before too much damage and nothing about summer/already damaged. Right now there are little holes all over. I haven't seen any actual bugs. It's still in its pot and I want to know what I can do to treat or prevent whatever it is that is causing these holes. I saw a full grown one and just fell in love with immediately and hope I can properly care for this one. Thank you :)

responder: An Ask Extension Expert Replied July 01, 2024, 12:21 PM EDT
response: Based on the photos and some other Ask Extension Q&A's I've read, I'm don't think you are dealing with leaf miners.  They tend to leave more of of "white tunnel" type damage, whereas your photos show little holes with clean edges.  Here's an Ask Extension from two years ago that seems to be addressing your problem as well:    Camperdown Elm Tree infected with small insects #792633 Asked May 25, 2022, 3:26 PM EDTI live in Ashland, Oregon and my Camperdown elm has small, 1/2 inch insects that fly and eat holes into the leaves, which then turn brown. Pictures are attached. I have just put a systemic around the trunk but was wondering if there is anything I could spray on the leaves to save them. They are full of small round holes and its all over the tree. Some of the leaves are turning brown and dying. The tree is infested with the insects. Thank You, Elizabeth Moore, <personal data hidden>. or <personal data hidden> Jackson County Oregon Expert Response This is likely the leafminer sawfly. Adults are tiny, black, fly-like sawflies which can be seen on new foliage on sunny days. Small, legless leafminer larva feed between the layers of leaf epidermis, resulting in large brown blotches that gradually coalesce into one large mine consuming the entire leaf. Large trees may be completely defoliated; however, as new growth continues in May, the trees begin to leaf out at the branch tips and replace lost leaves with little apparent effect. On Camperdown elm, however, the mines do not coalesce and the dark blotches are visible on the leaves that remain on the tree.  These sawflies overwinter as pupae in the soil. As trees begin to leaf out, adults emerge from the soil and are seen as black specks on the leaves. They begin to lay eggs, at first, in the angles where the secondary vein meets the midrib. As the larvae feed and grow, the mines appear to coalesce. Mature larvae drop to the soil to pupate. There is only one generation per year.  Pest monitoring Look for the small black adults as leaves unfold in the spring. They are most active when it is sunny within the tree canopy. The little black adults are easily visible on the upper leaf surface. Sticky cards placed on the sunny side of the plant in early April to provide early warning that monitoring should begin.  Infested trees can be treated with systemic insecticide. Once damage is obvious, it is usually too late to treat for the season. However, if treatment it timed correctly, the condition is easily controlled. Young leaf miners live in the ground through the winter.  https://pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/elm-ulmus-elm-leafminer  Other possibilities are leaf beetles or leaf weevils. Check out this publication:  https://extension.colostate.edu/topic-areas/insects/elm-leaf-beetles-5-521-2/    Chris Rusch Replied May 26, 2022, 11:51 PM EDT

responder: The Question Asker Replied July 03, 2024, 10:58 AM EDT
response: Hello, Thank you so much for taking the time to respond.  I am a bit confused as the other post you referred me to is talking about leaf miners, but you said you didn’t think I was dealing with leaf miners?  Also, all info says "Infested trees can be treated with systemic insecticide. Once damage is obvious, it is usually too late to treat for the season”… So my question is: Is my tree going to die? Or do I just have to wait until next spring to monitor and treat? Is there anything I can be doing right now.  Thank you so much and I apologize if I am not processing the information and missing something :)    On Jul 1, 2024, at 9:21 AM, Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied July 03, 2024, 11:42 AM EDT
response: Hi again, just consider the "leaf miner sawfly" as a "sawfly", I'd ignore the leaf miner reference because that is confusing.  Leaf miners leave dead, white tunnels in the foliage, not little holes.    The Pacific Northwest Insect Management Handbook has the following information on controlling sawflies:  Cultural control - pick off any larvae you see (caterpillars), possibly hose off plants with a strong stream of water.  You could hang up yellow sticky traps to possible catch one of the little bugs for better identification.    Biological control - insect predators include hemipterous sucking insects (for example, cicadas, leafhoppers, treehoppers, planthoppers, froghoppers, aphids, whiteflies, scale insects).  Chemical control for home use - applied as foliar spray you could try acephate, neem extract, carbaryl (Sevin), cyfluthrin, or spinosad.    Because your tree is about 8' tall, you should be able to use an all-purpose ornamental contact insecticide and a hose end or pump-up sprayer.    I would suggest going to a really good, well-stocked garden center and ask for their recommendations for contact sprays.  You could also ask about any systemic insecticides appropriate for ornamental trees.  In the past, there used to be a variety of water-in/drench type products, tablets that could be inserted into the cambium layer of the tree, as well as sprays.  I am not sure what is available these days.  One caution, systemic insecticides can harm beneficial insects such as honeybees, so my recollection is that systemic insectides have been gradually taken off the market.  Reading some on-line posts, one person's tree died the next year while another person's recovered and was fine.  If it was my tree, I would "baby it", care for it, spray it, water it, maybe fence it to keep away deer or mice from any further damage/stress, and wait and see.  Prune it in the late winter months then fertilize in early spring.  Rake up any fallen leaves from below the tree for good sanitation.    Good luck!

responder: The Question Asker Replied July 07, 2024, 11:22 PM EDT
response: Sorry for the late reply. Wow, what an extensive answer! I can’t tell you how much I appreciate all the time and effort you put into helping me. Yes, the names were confusing me :). I. Will continue to research and I will take all this info to the best nurseries I know to get the best info on contact sprays. And will make sure I am not harming any of those precious little bees!  Well, I’ve already named it Seymour, so he will be getting lots of TLC and crossing my fingers.   Thank you so much again! Kristen :)  On Jul 3, 2024, at 8:42 AM, Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied July 11, 2024, 11:22 AM EDT
response: Best of luck nursing Seymour back to health!  I think that tree is in good hands.  Cindy Brown