Biology and harmfulness of Eriosoma (= Schizoneura) ulmi (L.) (Aphidinea, Pemphigidae) in elm

Abstract

The paper deals with the occurrence, development, natural enemies and harmfulness of a heteroecious aphid Eriosoma (= Schizoneura) ulmi (L.) which showed outbreaks in elm Ulmus glabra Huds. in Moravia in 2002. At main localities under study in Bílovice nad Svitavou and Brno-Jundrov, the aphid damaged about 63% leaves. Larvae of fundatrices hatched from mid-April and their development from hatching to maturity took about 14 days. Mature fundatrices occurred in May and reproduced for a period of 14 days. Their average physiological fecundity amounted to 311 larvae and ecological fecundity 291 larvae. Migrantes alatae occurred in galls from 18 May to 15 June and their physiological fecundity was about 22 larvae. Leaves were damaged even by 3 galls of an average length of 41 and width 11 mm. Sucking affected on average 11 cm<sup>2</sup>, i.e. 27% (in case of the occurrence of 2 or 3 even 100%) leaf area. Natural enemies killed 90% aphids. A bug Anthocoris confusus Reut. killing aphids in 80% galls was the most effective control agent. Its eggs occurred from 25 April to 25 May and nymphs from 3 May to 25 June. Larvae of Syrphidae [mainly Syrphus ribesii (L.)] killed the aphids in 4 and birds in 6% galls. E. ulmi should be considered to be an important occasional pest of orchards and forests.

Biological Flora of the British Isles: Ulmus glabra

“…The elm‐currant aphid Eriosoma ulmi L. produces rolled leaf galls, and alternates with secondary hosts of Ribes spp. Damage has been reported by this aphid on between 61% and 82% of leaves in the Czech Republic and Poland (Kmieć & Kot, ; Urban, ). Second, the elm sack gall aphid Tetraneura ulmi L. produces brown, bean‐shaped galls on elm leaves, with grasses as the secondary hosts.…”

“…Poland (Kmieć & Kot, 2010;Urban, 2003b). Second, the elm sack gall aphid Tetraneura ulmi L. produces brown, bean-shaped galls on elm leaves, with grasses as the secondary hosts.…”

Aphid galls as a double food source for woodpeckers

“…The great spotted woodpecker would seem the only bird species feeding on both aphids and their honeydew from galls. The Eurasian red squirrel Sciurus vulgaris would be the only other vertebrate behaving similarly, when the number of aphids and the amount of honeydew in galls of the elm‐currant aphid Eriosoma ulmi are largest (Janiszewska‐Cichocka, 1971 in Urban, 2003), although there is no mention of this occurrence in a recent review of the Eurasian red squirrel's diet (Krauze‐Gryz & Gryz, 2015). Such scarcity of previous reports, as well as the obvious lack of interest in galls on the part of several birds during my observations, would point to rare behavior.…”