Cottonwood leaf-blotch-miner moth project
John Smiley
Location: Owens Valley Lab near Owens River, Inyo County, CA

Host plant: Fremont Cottonwood (Populus fremontii; Salicaeae)
Herbivore: Cottonwood leaf-blotch-miner moth (Phyllonorycter sp. (possibly nipigon); Lepidoptera: Gracillariidae)

Reference:

Biology and Systematics of the North American Phyllonorycter Leafminers on Salicaceae, with a Synoptic Catalog of the Palearctic Species (Lepidoptera: Gracillariidae) 2001. Donald R. Davis and Gerfried Deschla, Smithsonian Contributions to Zoology number 614. Smithsonian Institution Press pp. 1-88.

Field Notes: This moth has persisted for the past few years (at least since 2002) in outbreak numbers on the cottonwood trees at the Owen Valley Labs (OVL). Local Bishop residents have noticed the moth both because of its abundance, swarming into screens and in yards in Bishop, but also because its infestation prevents the cottonwood foliage from turning bright yellow in the autumn. For example in November there was a short article in the Inyo Register about the moth and its effect on the fall colors in town.

In the summer of 2003 I observed a major emergence of adults in September, and collected large numbers. In late June of 2004 there was a smaller emergence, but even then it was easy to collect several hundred by sweeping a net through the air under the trees. In October 2004 there was a very large emergence, which persisted into early November.

In late November and early December there was a very hard freeze (as low as -15 degrees C) at OVL. It will be interesting to see if this reduces winter survivorship and next summer's populations.

Blotch mines on leaf of Fremont Cottonwood (Populus fremontii) 10-04 Click on photo to see larger version	Leaf undersurface 10-04 Click on photo to see larger version
	Leaf upper surface Click on photo to see larger version