Blue Spruce loosing needles
I have four Blue Spruce. They are 50 years old an 40 feet tall. The needles are turning brown and dropping. We do not see any bag worms. I have read that these trees are prone to a fungus. Any help on treatment would be appropriated. Thank you, Pat Bristow
New Castle County Delaware
Blue spruce in our area has suffered from environmental extremes in temperature, wind, and irregular rainfall. With stress comes more susceptibility to disease caused by fungi, and insect pests. One common needlecast disease is Rhizosphaera needlecast caused by a fungus. It can be managed by reducing stress by improving soil and by watering trees during times of drought. A fungicide can be applied to help control the fungus, but proper timing and application coverage could be challenging on a large 50 ft tree. Chlorothalonil, sold as Bravo, is the best choice to apply, but you would need good spray equipment. It might be best to call a tree company, a certified arborist who will treat the tree to save it. Fungicide treatments should go on in early May, and then at least two more times, about 10 days and 20 days later. It will be costly. Affected needles will still drop, but the fungicide protects the new needles emerging and elongating in the spring.
Thank you for contacting Cooperative Extension,