KMXT 100.1 FM Public Radio in Kodiak, Alaska
Close up of spruce aphids. Photo by Elizabeth Graham
Kayla Desroches/KMXT
Kodiak residents have seen aphids chewing away at their trees before, but this year they’ve arrived earlier and spread further into southcentral Alaska. A few residents have noticed the change in their trees over time, like naturalist Stacy Studebaker, who wrote “Wildflowers and Other Plant Life of the Kodiak Archipelago”.
She says she and her husband came back from vacation in mid-July and got a call from her neighbor about the trees in the area, which she says were brown.
“And then we also noticed that there were just an unusual amount of spruce needles falling on our deck and driveway, absolutely everywhere. So, I got out my hand-lens, my magnifying glass, and my macro-lens on my camera, and I went out and took pictures of some of these dead needles and lo and behold, there were the wee beasties.”
While the green bugs don’t kill trees, Janice Chumley – the integrated pest management research technician with the Kenai Cooperative Extension Office – says in large numbers, they can suck Sitka spruce trees dry. Literally.
“Aphids have sucking mouth parts,” says Chumley. “So, they stick their proboscis in there and they suck some of the juices out, and as you know, when spruce needles don’t have any juice, they tend to turn brown and fall off.”
Chumley says in addition to showing up in Kodiak, aphids this year have been found across Kachemak Bay by Halibut cove and along the other side in the Homer area.
“This time, due to our mild winters and warmer, dryer summers, the number has grown significantly, and homeowners are now noticing that their trees appear to be losing their needles from their tree trunk all the way out to the tips.”
But by the time people start to notice that damage, she says the aphids have already left the tree.
“They’re looking for new hosts, and they will lay eggs in those trees over winter and if there is not a significantly cold winter to kill a large portion of them, you can expect this damage to continue. Historically, spruce aphids have a boom-bust cycle, and the boom cycle lasts one-to-three years. Possibly three.”
She says landowners should expect another summer of aphids, but there are measures you can take to strengthen the trees on your property.
“Our trees have adapted to being cooler and wetter than they have been for the past few years. So, watering a tree, and that means one to two inches around the drip-line of the tree each week, is important to provide tree health. Also, not compacting the soil, not running it over with putting four wheelers or parking snow machines under them, stacking wood underneath them on their root zone.”
She says spring is a good time to water the trees. For more information, check out this flyer about the spruce aphid.
