Canadian Forest Service Publications
Seasonal natural history of aphidophagous Syrphidae (Diptera) attacking the balsam twig aphid in balsam fir (Pinaceae) Christmas tree plantations. 2016. Berthiaume, R.; Hébert, C.; Pelletier, G. (Georges); Cloutier, C. Can. Entomol. 148: 466-475.
Issued by: Laurentian Forestry Centre
Catalog ID: 36242
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The balsam twig aphid, Mindarus abietinus Koch (Hemiptera: Aphididae), is one of the most important pests of balsam fir (Abies balsamea (Linnaeus) Miller; Pinaceae) grown as Christmas trees in eastern North America. Aphid feeding on the current-year shoots results in needle distortion and shoots stunting, which reduces the aesthetic value of balsam fir trees and can have substantial economic impact. Syrphidae (Diptera) fly predators attacking this aphid are poorly known. We identified four species attacking the balsam twig aphid. Syrphus torvus Osten Sacken (Diptera: Syrphidae) was the most abundant species followed by Eupeodes lapponicus (Zetterstedt) (Diptera: Syrphidae) and Eupeodes americanus (Wiedemann) (Diptera: Syrphidae). We described the seasonal natural history of the two most abundant syrphids feeding on this aphid and we studied their synchrony with their prey. Syrphid larval density on balsam fir shoots increased rapidly and closely followed density of the balsam twig aphid. We also reported heavy parasitism of syrphid pupae by two Hymenoptera on tree foliage but lower parasitism on pupae in the soil under trees. Several cases of multiple parasitism and hyperparasitism were observed in syrphid pupae under trees. Abundance of predaceous syrphid species was higher in untreated balsam fir plantations compared with treated plantations. More research is needed to understand the role and the impact of these predators on balsam twig aphid population dynamics.
Plain Language Summary
This study made it possible to identify four species of syrphid flies (order Diptera) that attack the balsam twig aphid. These are little-known predators. Researchers described the biology of the two most abundant species and studied their synchrony with aphids. The density of syrphid larvae on balsam twig shoots increases rapidly early in the season (May-June) and nearly matches the density of balsam twig aphids.
Further studies are needed to understand the role and impacts of these predators on aphid population dynamics.
The balsam twig aphid is one of the most important pests affecting balsam fir grown in Christmas tree plantations in eastern North America. The aphid causes damage to the needles and small branches that can lead to significant financial losses for these plantations.