"Pineapple" or "Pseudocone" galls occur on several species of Spruce trees including;
Norway, Sitka, Englemann and Colorado blue. They are a chemically induced growth distortion caused by a small aphid like insect called a "Pineapple gall adelgid" that lays up to one hundred eggs, one of each of up to 100 Spruce needles at the tip of the new growth. When the new aphids hatch they begin to suck on the soft new growth needles which in turn provokes the gall like growth reaction as the needles begin to swell and end up morphing into each other.
At first glance these pineapple shaped galls can be easily mistaken for cones (thus the name "pseudocone"). The image above shows a newly formed gall beside a seed cone on an Englemann Spruce tree.
The inside of the gall is rather fibrous and "woody" with small pockets. Spraying the galls to get rid of the insects is to no avail as the aphids are usually well protected inside the gall structure.
The pineapple galls end up drying out and dying leaving a dark brown carcas behind that does not do any real harm to the tree but can stunt growth to the branchet it has grown on. In some instances the branchlet will keep growing past the gall while in others the gall halts the growth all together for that branchlet.
"Pineapple" or "Pseudocone" galls occur on several species of Spruce trees including; Norway, Sitka, Englemann and Colorado blue. They are a chemically induced growth distortion caused by a small aphid like insect called a "Pineapple gall adelgid" that lays up to one hundred eggs, one of each of up to 100 Spruce needles at the tip of the new growth. When the new aphids hatch they begin to suck on the soft new growth needles which in turn provokes the gall like growth reaction as the needles begin to swell and end up morphing into each other.
At first glance these pineapple shaped galls can be easily mistaken for cones (thus the name "pseudocone"). The image above shows a newly formed gall beside a seed cone on an Englemann Spruce tree.
The inside of the gall is rather fibrous and "woody" with small pockets. Spraying the galls to get rid of the insects is to no avail as the aphids are usually well protected inside the gall structure.
The pineapple galls end up drying out and dying leaving a dark brown carcas behind that does not do any real harm to the tree but can stunt growth to the branchet it has grown on. In some instances the branchlet will keep growing past the gall while in others the gall halts the growth all together for that branchlet.
Galls are amazing... the huge variety of galls and gall forming insects never fails to astound me. This one's new to me so thanks!
ReplyDeleteThanks Micah, I´ll check out your blogs.
ReplyDeleteDo you think it would help to apply a systemic insecticide to the tree?
ReplyDeleteHi-Yield makes Di-Syston (systemic insecticide granules) which I've used to control aphids on my Crab Apple tree.
I'm considering using Di-Syston on a blue spruce tree that has pineapple galls. Your opinion, please ?? Thanks!