Ophiomyia nasuta Melander

Ophiomyia nasuta (Melander)

(Fig. 94)

Material examined. MASSACHUSETTS: Franklin Co., Northfield, 276 Old Wendell Rd., 5.v.2016, em. 20– 21.v.2016, C.S. Eiseman, ex Taraxacum officinale, #CSE2476, CNC654194 (1♂).

Host. Asteraceae: Taraxacum officinale F.H. Wigg.

Leaf mine. (Fig. 94) Frost (1924) stated that the larvae “mine on the stalks and the petioles of leaves, sometimes working their way to the leaves themselves.” He reported that the petiole mines are so shallow that they are essentially invisible after the larvae have moved on. The mine of our specimen was first noted on 21 April, when the young dandelion plant had just two small leaves, the lowermost being 4–5 cm long. At this time the mine occupied the entire petiole of the lowermost leaf and extended to within 1 cm of the leaf apex. It was visible as a broad, whitish track extending irregularly to either side of the midrib, without evident frass. On 5 May, the second leaf was now larger than the first, and it now had a similar mine, likewise extending almost to the apex. The plant now had a third leaf, which was not visibly mined on the upper surface, but on the lower surface the larva had mined up the petiole and was visible in a small blister to one side of the midrib, at the base of the leaf blade. It was pale yellow and was evidently in the process of pupariating.

Puparium. The puparium remained pale until 17 May, at which point it darkened due to the adult developing within. When the adult emerged 3–4 days later, the empty puparium was colorless and transparent.

Distribution. Across northern North America from YT to QC, south to northern CA, CO, and NC; Europe;

Japan.