Euura lasiolepis

According to Smith's photos and Russo's drawings, Euura lasiolepis forms narrow, tapered stem galls. However, abrupt, potato-like galls have also been observed on Salix lasiolepis. These may be induced by a distinct species, though Smith speculates that "it is very unlikely more than a single [Euura] species attacks 1 species of willow." Smith also states that the stem gallers on his "lasiolepoid willows" are "virtually identical structurally," further suggesting that the morphological differences between Euura lasiolepis and its sister species Euura lemmoniae are not diagnostic in the absence of a host ID and likely do not indicate distinct morphological species on either host. In his 1970 paper Smith notes that the lasiolepis-group stem gallers form galls that are "usually more bulbous than those of the exiguae group."

Euura lasiolepis n. sp.

[Photos of many examples of this gall appear in Figure 35, page 16 of the pdf]

GALL.—Lasiolepoid-type (Fig. 35); thick walled, tortuous; surface smooth, shiny, or corrugated; color yellow-green except purple to red in bright sun; 20-70 mm long X 3-21 mm wide; 1-5 larvae/gall; willow a shrub or small tree usually under 5 m, but to 10 m in wet sites.

Host.—Salix lasiolepis Bentham.

Range.—With the willow at least from Monterey County north to Mendocino County, California, and from the coast to the west face of the Sierra Nevada (but see subsequent discussion).

Remarks.—Emergence and oviposition from late February to early June, peaking in early March; coast and valley populations with cocooning from October through February. Locally very abundant on susceptible willow clones along roadside ditches and sloughs, and marshy areas along foothill streams. East of the Sierra Nevada Divide from 1225—1825 m is a black Euura on S. lasiolepis, average saw L:W = 17.5:1, dimensions 1.56 mm X 0.09 mm, body slightly paler and smaller than coastal (black) phase. For status of this, another form on 3". rigida, and sibling species on S. scouleriana, see discussion of speciation in stem-galling Euura.

Euura lasiolepis

Image Details

Further Information (4)