Conifers/Brown needles on Loblolly Pine Tree
QUESTION: Sir: I have about 500 loblolly pines on my property that were planted by Tennessee Forestry Service; I noticed last fall that one of the pines had developed an unusual browning of the needles. At first I thought this was a normal process where the tree sheds its needles but became very concerned after it became worse. At this point, about 2/3 of the needle end is brown; Can you please tell me how I can save this tree and keep this problem from spreading? thank you very much... Rod
ANSWER: Looks like a disease called needle cast. Needle cast is a broad group of fungal diseases that cause conifers to shed needles. The symptoms of needle cast first appear on needles as light green to yellow spots, which eventually turn red or brown. Growth of the fungal pathogen from the spots on the needle will cause the death of the entire needle. This shedding of needles can be more serious to conifers than losing leaves is to deciduous hardwoods. There are over 40 kinds of needle casts in North America. Infected needles usually turn red to brown from their tips beginning in winter or early spring. By mid to late spring the death of infected needles is well advanced giving diseased trees a red to brown "fire-scorched" appearance. Tiny black fruiting bodies (spore producing structures) form on the surface of the needles before or after the infected needles are shed.
Pines have two sets of needles. Since this effects only the older needles it will not kill the tree. You can get growth loss but after the old needles fall and the new growth has matured you will not be able to tell much difference. In a plantation no control is necessary. There are fungicides that can be sprayed on the foliage but with 500 trees it is not needed. IF you use a fungicide (which will be a large job with this many trees and not necessary) here is the recommendation. Fungicides also can be used as part of a management program. Infected trees can be sprayed with bordeaux mixture 8-8-100 (8 lb hydrated lime, 8 lb copper sulfate, 100 gal water) or chlorothalonil fungicide. Fungicides should be available at local nurseries, garden supply stores, or feed stores. Fungicides provide protection against infection and prevent spread of the disease within the tree. They should be applied to the tree when the new needles are half developed and again when they are full length.
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QUESTION: Sir -- thank you for your prompt response. The Loblolly that is infected has not lost its needles (yet); however there is new growth (candles) - I presume I should spray these and the trees in the immediate area of the infected tree? I certainly do not want this to spread to my other trees. I have Daconil and also Fung-onil are these effective against the needle cast; If not, I will spray the trees with the bordeaux and/or chlorothalonil - what ever is the most effective to arrest this fungal disease.
How effective is the fungicide treatment - will it save the tree? Look forward to your response. Thank you very much - I really appreciate your expertise. regards Rod Boysen
I would try the daconil. The treatment on the new needles is very effective. Do not expect any change in the needles that have already turned brown. The new needles should be green and not have the spores on them. Good Luck. I would spray them now and again in about two weeks.