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American elm leaf aphidOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
All adult viviparae of Tinocallis ulmifolii are alate. Immatures (see first picture below) are greenish yellow with long capitate hairs. Alatae (see second and third pictures below) are pale yellow to greenish to reddish green to dark gray-green (for latter see Jensen in Aphidtrek). The antennal terminal process is about equal to the length of the base of segment VI, and antennal segment III has 5-12 secondary rhinaria. Tinocallis ulmifolii usually have several (wax-bordered) dusky longitudinal streaks on the head and pronotum, but they never have just a single narrow dark mesial stripe (cf. Tinocallis zelkowae, a Japanese species invasive in USA, which has a single narrow dark dorsal mesial stripe). The Tinocallis ulmifolii head and pronotum are without spinal processes (cf. Tinocallis ulmiparvifoliae, another invasive species, which has 2 pairs of spinal processes on the pronotum).
Images above, copyright Claude Pilon, all rights reserved.
On abdominal tergites I & II there are two pairs of finger-like dorsal tubercles (see lateral view above); these are large and prominent, usually longer than their basal widths, with smaller ones on succeeding segments. There are also longitudinal rows of white wax spots on the abdomen, as well as dusky spots around hair-bases (see dorsal view below). The forewing veins are not dark-bordered (cf. Tinocallis platani, which has the forewing media vein and Cu1b veins thickly and rather evenly dark-bordered). The siphunculi are short, truncate, and more or less widened at the base. The cauda is knobbed and the anal plate is bilobed. The body length of Tinocallis ulmifolii alatae is 1.5-2.0 mm.
Note: There is some seasonal variation in this species. The vertex in the early summer form is pale. In the late summer form there is dark mottling around the antennal sockets, and on sides of the head, front, and muscle plates (Quednau, 2001).
Image above, copyright Claude Pilon, all rights reserved.
Tinocallis ulmifolii feed on the undersides of leaves of elm (Ulmus spp.), especially American elm (Ulmus americana). Apterous oviparae and alate males occur in September-October (Palmer, 1952 as Myzocallis ulmifolii) and eggs are laid near the buds. The American elm leaf aphid is widely distributed in North America.
Other aphids on the same host
Tinocallis ulmifolii has been recorded on 3 species of Ulmus (Ulmus alata, Ulmus americana, Ulmus thomasii), but is mainly found on Ulmus americana.
Blackman & Eastop list 14 species of aphid as feeding on American elm (Ulmus americana) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 7 as occurring in Britain (Show British list).
Damage and control
The American elm leaf aphid produces abundant amounts of honeydew which in some situations can produce serious nuisance problems. High aphid populations cause premature leaf yellowing and drop. Soil injected applications of imidacloprid have given effective control of elm leaf aphid.