Host preference of the crapemyrtle aphid (Hemiptera: Aphididae) and host suitability of crapemyrtle cultivars.

Crapemyrtle aphids, Sarucallis kahawaluokalani (Kirkaldy), are a common pest of crapemyrtle (Lagerstroemia spp.) throughout the southeastern United States. Breeding programs have produced >100 crapemyrtle cultivars that vary in floral color, plant height, and disease resistance, but these programs did not evaluate insect resistance as part of the selection process. In this study, the host suitability of crapemyrtle cultivars and host preference of the crapemyrtle aphid were tested using the following seven crapemyrtle cultivars: 'Carolina Beauty', 'Byers Wonderful White', 'Apalachee', 'Lipan', 'Tuscarora', 'Sioux', and 'Natchez'. Host suitability or aphid preference may be affected by cultivar attributes of plant parentage, source of Lagerstroemia fauriei Koehne germplasm, and mature plant height. Host suitability was evaluated by measuring daily and total fecundity under no-choice conditions. Host preference of the crapemyrtle aphid was tested in a choice experiment that used eight crapemyrtle cultivars; the seven used in the no-choice experiment plus Lagerstroemia speciosa L. In the no-choice experiment, aphid daily fecundity was not different among the crapemyrtle cultivars, but aphid total fecundity was different for the factors cultivar, plant parentage, source of germplasm, and mature plant height. Crapemyrtle aphid host preference in the choice experiment indicated that there were differences among cultivar, parentage, source of germplasm, and mature plant height. Results from this study are useful for plant breeding programs that have the objective of producing aphid resistant cultivars.