Arthropod-Plant Interactions (2014) 8, 9-15

Lori A. Nelson, Dylan N. Dillaway and Lynne K. Rieske (2014)
Effect of an exotic herbivore, Adelges tsugae, on photosynthesis of a highly susceptible Tsuga host, with notes on conspecifics
Arthropod-Plant Interactions 8 (1), 9-15
Abstract: Hemlocks are significant components of temperate forests of Asia and North America, and in eastern North America, they are threatened by an exotic herbivore, the hemlock woolly adelgid, Adelges tsugae. The adelgid is native to Asia and northwestern North America, but is highly invasive in eastern North America where natural enemies are unable to regulate populations and eastern hemlock, Tsuga canadensis, is highly susceptible. In order to gain a better understanding of the metabolic effects of A. tsugae on eastern hemlock, we evaluated its effects on photosynthesis and also evaluated photosynthesis on Tsuga species from various geographic origins. We measured light-saturated photosynthesis (A_sat) and dark respiration of T. canadensis that were infested with adelgid and found a significant decrease in A_sat and a small but significant increase in dark respiration, suggesting that A. tsugae triggers a physiological response in eastern hemlock by decreasing metabolic activity. In a separate experiment, we also measured A_sat of five different hemlock species, including eastern hemlock, the Pacific Northwestern T. heterophylla and T. mertensiana, and the Asian T. diversifolia and T. chinensis. Only weakly significant differences in A_sat were found, with the highest rate in the eastern North American T. canadensis and the lowest in the Pacific Northwestern T. mertensiana. The relatively high photosynthetic rate of T. canadensis could possibly play a role in its susceptibility to A. tsugae. A better understanding of this metabolic response could help develop effective management strategies for combating the highly invasive A. tsugae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Lynne K. Rieske

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Adelges tsugae	Hemlock (Tsuga)