Jack pine pest

Question: Hello. I have a few jack pine that are infected with a pest that is currently in larval stage I think. Could you please help to identify this pest and offer possible treatments?

responder: Julie Crick  Replied August 28, 2024, 8:42 AM EDT
response: Hi Tom, This looks like the zimmerman pine moth in the larval stage. Have you observed dieback of branches? If not, then you caught it early.  https://hort.extension.wisc.edu/articles/zimmerman-pine-moth/  https://extension.entm.purdue.edu/publications/E-40/E-40.html  The larval stage you found will overwinter in those sap encrusted havens. In the spring, the larvae will emerge and bore into the bark where it feed under the bark. Best chance for control is to use an insecticide to coat the bark and branches before it emerges next spring.  If your pines are small, you may have some success picking off the larvae at this point. Look in the crooks where the branch connects to the trunk (as you have already likely seen).  The articles describe insecticide options and treatment schedule. Always read and follow label directions when using a chemical application.   Please let me know if you have any questions.  Thank you! -Julie

responder: The Question Asker Replied August 30, 2024, 12:19 PM EDT
response: Plant diseases:  Hello Julie and Extension.  Thank you for your reply. I appreciate it.  This is a degraded five acre site that I purchased four years ago. Existing tree species:  White Pine (~12-15’)  Douglas Fir (~20+’)  Red Pine (mature)  Jack Pine (seedlings and one ~10’)  Norway (?) Spruce (one only, 5’)  Blue Spruce  (one only, 5’)  Choke Cherry (mature)Planted by me:  White Pine   Red Pine   Jack Pine   Norway Spruce   Concolor Fir   Green Giant Arborvitae   3x Locust (2.5” dia.)  American Larch  Tulip Poplar  Sugar and Red Maples  Various fruit trees     It seems like my trees are suffering from multiple pests at this site. An arborist identified White  Pine Weevil on my White Pines and I identified Swiss Needlecast on my Douglas Fir two years ago. I imagine that the weevil may be infesting other species.  I have treated the weevil with pyrethrum (not pyrethroid) and the Needlecast with Actinovate the past two Springs.  The 10’ Jack Pine showed signs of dieback last Fall and is now totally brown.   On my site visit last week I noticed the damage to the Jack pine and Blue Spruce. You have identified these pests as Zimmerman Pine Moth and Cooley Spruce Gall Adelgid respectively. Thank you. Obviously I have my work cut out for me.   My treatment plan is something like the following:Physically remove any visual signs of disease.Next Spring treat all Pine, Spruce and Fir with a pyrethroid.Continue to treat Doug Fir with Actinovate (this has been vey effective as I have seen no signs of the Needlecast since application has begun).       Can you please comment on the current situation and my proposed treatments?  Thank you again.Regards, Tom Sent from my iPad On Aug 28, 2024, at 07:42, Ask Extension wrote:﻿

responder: Julie Crick  Replied September 04, 2024, 4:12 PM EDT
response: Hi Tom! Wow, thank you for planting and watching over your trees!  I do think you treatment plan is a good one. I looked up growing degree days (base 50) to help with the timing of your spring treatment and it looks like the zimmerman pine moth can emerge in a range of 25-100 GDD. So, if you watch growing degree days, you may want to start treatment at 20 then repeat to ensure you effectively kill the larvae.   Below is a link to learn more about growing degree days: https://www.canr.msu.edu/ipm/agriculture/christmas_trees/growing_degree_day_information  Also, are you in contact with Rod Denning, the conservation district forester in Oceana County? It might be nice to have him come out to the site to make recommendations on future plantings, or keeping the existing trees health. Rod's contact information is at the link below: https://www.oceanaconservation.org/our-team  Good luck, Tom!! -Julie

responder: The Question Asker Replied September 14, 2024, 7:57 PM EDT
response: Hello Julie.   Thank you for your reply. I appreciate it.  I will work on the timing for the spraying and think that it will be mid to late March. Since I am dealing with multiple pests, I plan on spraying at least twice. Also, I realize that this will be a multi year task at best.  Rod has been to my site at least once, probably twice. I also had an arborist from Bartlett Tree Service walk the site. He is the one that told me about the White Pine weevil.    I was at the site (I call it Knapweed Knoll) and found something very interesting. The photos are not all that good, but it is a woody growth on an immature Jack Pine. It is about 3” in diameter and there is a smaller one below and to the right. I scraped it with my thumbnail and it is green underneath. Any ideas? Something that may be related to this; there is a larger Jack Pine on the site that started to turn brown last Summer but I did not pay much attention as it seemed that it was fairly well established in under no immediate threat. Well, this Spring it was completely dead. I took a quick look but could not see any readily apparent reason for this. Any suggestions on that?   Photos attached.Regards and thanks again, TomSent from my iPad On Sep 4, 2024, at 15:12, Ask Extension wrote:﻿

responder: Julie Crick  Replied September 16, 2024, 10:16 AM EDT
response: Hi Tom, Glad you are connected to the local professionals! The round woody growth on the jack pine is a rust gall, caused by a fungus. It could be a pine-pine rust gall, or an oak-pine rust gall.  https://extension.umn.edu/plant-diseases/pine-gall-rusts Because there is no treatment for these galls, or cankers, it is best to prune them out when discovered. The issue is when they are found on the main stem, and pruning out the gall is destructive to the tree. Because you are establishing a forest, I would recommend removing (and replacing!) all jack pine with a gall.  The fungus is endemic in the landscape, so hopefully fungal spores will more often land on branches rather than the trunk of trees.  Not great news, but at least you caught it early!  Thanks, Tom, -Julie