Back on 18 August, I noticed Rob Edmunds’ post on Twitter about his find of Liriomyza pisivora mines on the Everlasting pea in his garden, which led me to check, the next day, the plants growing at Cardiff’s Grangemoor Park. I found plenty of leafmines but my finds were inconclusive – there are several species that form similar mines so I needed to get better photos, if possible transparent images that showed the frass distribution in the mines.
So, when I visited Grangemoor again on 28 August to look for the Wasp spiders that had been reported the previous day, I also took the opportunity to look again at the Everlasting pea plants and took several more photographs. From them, I could see that in some of the mines the frass had been deposited as thin lines alternating from one side of gallery to the other.
Those images were good enough for Barry Warrington, the national recorder of the Agromyzidae family of flies, to confirm that I had indeed found Liriomyza pisivora and, a splendid surprise, that this was the first ever record of these flies in Wales!
The host plant in this instance, Broad-leaved everlasting-pea (Lathyrus latifolius), is a relatively recent arrival at Grangemoor, though it is now sprawling abundantly over bramble bushes and along scrubby hedgerows in several parts of the park. So far, I’ve only found Liriomyza pisivora mines in one relatively small area but, perhaps, in time, they will spread throughout the park.