Project Description: (2016-04-15) This project includes observations about trees that may be infested by spruce aphids Elatobium abietinum. According to the Alaska Region U.S. Forest Service - Symptoms of spruce aphid infestation have been observed on the Kenai Peninsula. "The spruce aphid is a small green, soft-bodied insect about 1 to 1.5 mm in size. Both winged and wingless forms occur. Spruce aphids feed by inserting their needle-like mouth-parts into host foliage and sucking the sap from the needles. First symptoms of feeding are yellow patches on the needles. If the population increases, discoloration intensifies and affected needles turn brown and drop prematurely." USDA
Start Date: April 15, 2016
Project Lead: Pending
Observer Invite: In recognition of the expansion of spruce aphid in Alaska, the LEO Network is inviting observations about outbreaks of spruce aphids. Photos showing infected trees as well as close-ups of aphids on branches preferred.
Past LEO AK Webinar & Presentation Resource:
March 21, 2017 – Presentation: Aphids, Caterpillars, and Moths, HO MY! Presenter: Jessie Moan, Statewide IPM Technician, Integrated Pest Management Program , Cooperative Extension Service, University of Alaska Fairbanks
Forest Health Protection and State Forestry Organizations: Recognizing Spruce Aphid, by Dwight Scarbrough writes, "Spruce aphids are small (1/16 of an inch), soft-bodied, mostly wingless insects. They are light green when young and turn an olive green when mature. Winged adults have two pairs of wings, with the front pair being much larger than the hind pair. Like other aphids the spruce aphid has sucking mouth parts which they use to suck the sap from foliage. They feed gregariously and secrete “honeydew” which attracts ants. Foliage damage appears similar to some needle cast diseases. The presence of the insect is necessary to identify spruce aphid as the cause." Source: USDA U.S. Forest Service
Reference Materials:
Forest Health Conditions in Alaska - 2013, by A Forest Health Protection Report. Page 24 - Spruce Aphid Elatobium abietinum (Walker), "Little defoliation was attributed to spruce aphid during the 2013 aerial detection survey. A small amount of damage, totaling 158 acres, was found near the Petersburg Airport on Mitkof Island, across from the airport on Kupreanof Island, and near Tee Harbor in Juneau. Weather plays a major role in controlling aphid populations, which cannot survive long exposures to temperatures <15 F°. Southeast Alaska experienced a moderate winter in 2013, with temperatures rarely falling below 15 F° in some areas, yet little damage was recorded. Spruce aphids reproduce asexually, which contributes to sudden increases in activity when conditions are ideal. Large scale outbreaks of spruce aphid have occurred in Southeast Alaska following mild winters in 1992, 1998, and 2010. Spruce needle aphids feed on older needles of Sitka spruce; often causing significant needle drop (Figure 27). After a few years of defoliation, some trees retain only the most recent year or two of foliage. Spruce aphids usually favor the same trees year after year and outbreak after outbreak." Citation: FS-R10-FHP. 2014. Forest Health Conditions in Alaska 2013. Anchorage, Alaska. USDA Forest Service, Alaska Region. Publication R10-PR-035. 81 PAGES
Sap-Sucking Insects, Gall Fromers and Mites – "Symptoms/Signs: The spruce aphid is a small green, soft-bodied insect about 1 to 1.5 mm in size. Both winged and wingless forms occur. Spruce aphids feed by inserting their needle-like mouthparts into host foliage and sucking the sap from the needles. First symptoms of feeding are yellow patches on the needles. If the population increases, discoloration intensifies and affected needles turn brown and drop prematurely." Source: U.S. Forest Service, Field Guide to Insects and Diseases of Arizon and New Mexico Forests
Spruce and Giant Conifer Aphids – "Sitka spruce is periodically subjected to attack by the spruce aphid, which can produce severe needle drop and death of the tree. Spruce aphid outbreaks are usually preceded by mild winters, and normally last for a short time, perhaps two or three years. Since spruce aphids can reproduce throughout the year, large colonies may develop during mild winters. Aphid damage may become apparent in March or April before the new spruce growth begins. Populations continue to increase until early summer, when many of the aphids develop wings and fly off to infest new spruce. By midsummer the populations may reach a low point. This decline in aphid numbers during the late summer is due to numerous factors including migration by winged individuals, increased parasitism, and changes in the chemistry of the spruce needles. In the fall, the aphids may increase in number and infest the shoots that were produced earlier in the year. This second peak in September and October is usually not as damaging as the spring population, but significant defoliation may still occur if the autumn is a mild one." By Mark Schultz, Entomologists, USDA Forest Service, Alaska Region, and Ed Holsten, State and Private Forestry
Media:
Alaska Dispatch News – (2016-05-25) New bug brings back memories of spruce bark beetle devastation, "CHINA POOT BAY – It looks like the start of the spruce bark beetle kill of the 1990s, when mountainsides across the Kenai Peninsula turned gray, the biggest tree blight in North American history to that time. But it started just last year. A warming climate has powered the explosion of the spruce aphid (Elatobium abietinum) in the same areas where the bark beetle took off, on the south side of Kachemak Bay. Trees are losing their needles and turning gray, and some owners are cutting them down for fear of fire." Author: Charles Wohlfort, Alaskan Author, Broadcaster, Jounalist
