I have a blue spruce and sections of the needles are turning rust colored. It...
I have a blue spruce and sections of the needles are turning rust colored. It is next to another pine tree that has the same problem. A third tree, a Norway Spruce is starting to get rust colored needles as well. I've attached pictures of the blue spruce.
There are several fungal issues and diseases that Colorado blue spruce trees can develop over time that will result in needle loss and dead branches. Some diseases are treatable and some are not. It is important to get a proper diagnosis on what is causing the damage before applying any chemical or fungicide. For a proper diagnosis you may want to consider consulting with a certified arborist in your area. A certified arborist can diagnose your tree and make the necessary recommendations. To locate an arborist in your area visit the following website and in the top right corner click on - find a tree care service. From that point you can search by applying your zip code: http://www.treesaregood.com You may also consider sending a sample to MSU Diagnostic Lab. Call 517-355-4536 for sample instructions and fees or visit their website at: http://pestid.msu.edu
There are many issues that spruce trees encounter. I am including additional information with a brief explanation regarding them.
Links to issues that plague Blue Spruce trees. http://msue.anr.msu.edu/news/spruce_tree_problem_shows_symptoms_of_both_needlecast_and_branch_death
Cytospera Canker - This fungal disease tends to infect older spruce trees. You may begin to notice branches dying near the base of the tree first and eventually see it progress upward. You may also see a white resin on the trunk or branches. The white resin on the branches will resemble bird droppings. The following website will give you details on this condition and with pictures that will help you determine if your Spruce is dealing with this condition. http://www.pestid.msu.edu/LinkClick.aspx?link=Factsheets%2fCytospora.pdf&tabid=218&mid=834
Phomopsis - The initial symptoms are very subtle, just a slight discoloration of the needles. Eventually needles may turn brown or purple and drop. In the spring new shoots will expand and then rapidly wilt and die. Fungicides are available.More information and photos can be found at this website. http://web2.msue.msu.edu/bulletins/Bulletin/PDF/E2417.pdf
Setomelanomma - Very little is known about this pathogen. Needles on infected branches will turn yellow, then brown and will drop by the end of summer. Only the needles on the tips of the branches will remain. At this time there is no known control strategy.
Rhizosphaera needle cast. Rhizosphaera is a fungus disease that tends to infect inner needles first. The needles turn brown or purple and drop from the tree. If you have a good hand lens you can see the black fruiting bodies in the white bands of the needle. The following website provides more details and photos. http://ohioline.osu.edu/hyg-fact/3000/3059.html and
Stigmina - Very little is known about Stigmina. The symptoms are similar and the fruiting bodies could be confused for those of Rhizosphaera. Unfortunately the controls for Rhizosphaera do not appear to be effective for Stigmina. The following website gives some information on Stigmina. http://www.ipm.iastate.edu/ipm/hortnews/2008/2-6/Stigmina.html
I realize this is a lot of information but proper diagnosis is the key to successfully treating your spruce and maintaining its health. I hope this information helps you out in making the right decision.