(Question)
I hope you can help me save my 30-year-old dwarf blue spruce.
The new growth is bare, and I am wondering if it is the fungal disease called tip blight?
The spruce is growing in full south sun in Richmond Hill (York Region), in amended clay soil. It has thrived for 30 years so I don’t think it is related to how I look after it. It is more likely a disease. If so, what can I do to stop the spread?
Thank you in advance for your advice.
(Answer)
It is a little difficult to give you an definitive diagnosis but your problem could be one of three things.
- Diplodia blight, commonly called tip blight. This is a fungal disease which attacks Spruce trees, especially the Colorado Blue Spruce. It usually attacks trees that are already stressed and leads to needle browning & drop, tree disfigurement, loss of vigor and death of the terminal bud. If you look closely, you may see droplets of resin in the dead buds or shoots. If you suspect this is what you have, I would suggest you contact a certified arborist or tree care professional for an accurate diagnosis and a treatment plan, which may involve a fungicidal spray.
- Spruce Budworm could also be the culprit for the tree damage. This pest favors Balsam Fir, White Spruce, Black Spruce, Eastern Hemlock, Eastern White Pine, Larch and Jack Pine but if hungry, it will happily munch your Blue Spruce. Spraying the tree with Btk when caterpillars are actively feeding in mid to late June will control the population and keep your small tree safe.
- Gypsy Moth Caterpillar damage. This year has seen a tremendous increase in the Gypsy Moth population with many deciduous trees around the city of Toronto being totally defoliated. In the evenings, caterpillars will rappel down from the canopy of larger trees and feed on what is below. Their preferred diet consists of leaves of Oak, Birch, Beech, Aspen and Maple, but they will also eat evergreens such as Pine, Spruce and Fir. As above, spraying with Btk will help with population control but below you will find a link to more information on this pest with more control measures.
I hope this is helpful.