Species and Cultivar Influences on Infestation by and Parasitism of a Columbine Leafminer (Phytomyza aquilegivora Spencer)

Abstract

Columbine, Aquilegia spp., are regularly attacked by agromyzid leafminers, Phytomyza spp. Effects of columbine species and cultivars on infestation by the leafminer Phytomyza aquilegivora Spencer, and subsequent parasitism by hymenopterous parasitoids was evaluated in two-year field trials at four locations in central and north Georgia. Among 20 columbine taxa planted in non-irrigated, wooded sites in central and north Georgia, two selections (A. flabellata and A. caerulea ‘Dwarf Fantasy Mix’) were comparable to the moderately resistant native species A. canadensis. In irrigated sites in central and north Georgia, all cultivars were equally infested by the leaf miner. The most heavily attacked selections among all sites were A. alpina, A. chrysantha ‘Yellow Star’, A. caerulea, A. caerulea ‘McKana mix’, A. caerulea ‘Music hybrid’, A. skinneri, and A. x hybrida ‘Ruby Port’. The variegated selection, A. vervaeneana ‘Woodside’, sustained intermediate infestation levels as did A. vulgaris ‘Winkie Blue & White’. Cultivar influences on parasitism of leafminers was quantified at two sites. Eleven species of hymenopteran parasitoids representing three families were recovered. Leafminers infesting A. chrysantha ‘Yellow Star’ were most heavily parasitized at both locations. Chrysocharis pentheus Walker was the most abundant parasitoid, representing 41% of all parasitoids collected and 48.4% of the species reared from leafminers in central Georgia. Seladerma sp. was the only parasitoid reared from leafminers collected in north Georgia and represented 22.1% of all parasitoids obtained.