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Purple-spotted lily aphidOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
Adult apterae of Macrosiphum lilii (see first picture below) are yellow to yellow-orange, with the anterior half of the abdominal dorsum red. Antennal segments I-II are pale, but segments III-VI are dusky or dark. The secondary rhinaria on segment III are limited to the basal half or less (cf. Macrosiphum perchumani on Convallaria, which has the rhinaria scattered over almost the entire length). The antennae are set on prominent antennal tubercles, but the median frontal tubercle is small or undeveloped. The longest hairs on antennal segment III are 0.6-1.0 times the basal diameter of that segment. The apical rostral segment (RIV+V) is 0.8-1.1 times the length of the second hind tarsal segment (HTII). There is no sclerotization on the abdominal dorsum (cf. Macrosiphum badium & Macrosiphum insularis on Maianthemum, and Macrosiphum wilsoni on Disporum, all of which have the dorsum sclerotized and 'leathery') . The legs are mainly pale, with darkened 'knees', distal tibial apices and tarsi. The siphunculi are entirely black, contrasting with the pale yellow cauda (cf. Macrosiphum euphorbiae, which has the siphunculi pale like the cauda, albeit sometimes darker distally). The siphunculi are a little under twice as long as the cauda. The body length of adult Macrosiphum lilii apterae is 2.5-3.2 mm.
Note: The Macrosiphum species above that we compare with Macrosiphum lilii all feed on lilies, but except for Macrosiphum euphorbiae they usually occur on lily genera other than Lilium.
Images above by permission, copyright Hadel Go, all rights reserved.
Image above copyright Quaa under a Creative Commons License.
Macrosiphum lilii is monoecious holocyclic on lilies (mainly Lilium spp.). Monell (1880), who first described the species, reports that, if disturbed, all aphids in the colony unite in a swaying motion, presumably in an attempt to dissuade any potential predator. The aphids were described from bulbs imported to USA from Japan, and the species is now found widely in eastern USA. Interestingly though, Blackman in Aphids on Worlds Plants notes that the species has not subsequently been recorded in Japan.
Other aphids on the same host
Macrosiphum lilii has been recorded on 5 lily species (Lilium canadense, Lilium henryi, Lilium lancifolium, Lilium speciosum, Lilium superbum).
Damage and control
Monell (1880) reported that even when Macrosiphum lilii were present in great numbers "they did not injure or disfigure the plant to the same degree as other Aphides". This may be because they tend to spread out in a regular pattern over the stem and older leaves, rather than develop dense populations on the growing shoot. Advice on control methods if required can be obtained NCSE (North Carolina State Extension).