HOSTS AND DENSITY OF LYONETIA SPP (LEPIDOPTERA, LYONETIIDAE) MINING THE FOLIAGE OF WOODY ERICACEOUS AND ROSACEOUS PLANTS

Hosts and density of multivoltine Lyonetia latistrigella Walsingham an d L. prunifoliella Hubner were determined by sampling larvae and pupae on shoots of cultivated and wild plants in Connecticut between May an d October 1989 and 1990. Other hosts were determined by rearing adults from mines of L. latistrigella L. ledi Wocke, and L. prunifoliella co llected in Connecticut, Massachusetts, and British Columbia, and by ex amining the literature and the collection of D. L. Wagner. L. latistri gella mined 14 ericaceous species in 5 genera; L. ledi infested 2 Rhod odendron spp.; and L. prunifoliella used 5 rosaceous species in 3 gene ra, 2 Betula spp. (Betulaceae), and 2 Ceanothus spp. (Rhamnaceae). Whe n several hosts were compared, the density of L. latistrigella and L. prunifoliella was highest on Rhododendron 'P.J.M.' in a nursery at Wes tbrook and on Malus domestica Borkhausen 'Mutsu' in an orchard at Sout hington, CT, respectively. At Westbrook, the Ist generation developed on wild plants, and later ones mostly on potted Rhododendron; leafmine rs apparently moved from wild to potted plants. By contrast, mining at Southington started on apple and spread to other cultivated and wild species in later generations. At the nursery and orchard, cultivated p lants nearest to wild hosts had the greatest density of leafminers. In no-choice rearing, L. prunifoliella developed to adult on quince, Cyd onia oblonga Miller, and on pin cherry, Prunus pensylvanica L., but no t on 5 other rosaceous species. If susceptible plants in nurseries or orchards were grown further from wild hosts or if wild hosts near orch ards were removed, injury caused by Lyonetia spp. might be lessened.