The genus Lagerstroemia L. is native to Southeast Asia and comprises between 50 and 80 species, most of which are concentrated in tropical latitudes (Cabrera, 2004; Egolf and Andrick, 1978; Pooler, 2003). Of these, however, less than 10 species have been cultivated as ornamental plants, in particular L. indica L., L. fauriei Koehne, L. subcostata Koehne, and L. speciosa Pers. (Pooler, 2006b). Breeding and selection efforts in the United States, and specifically at the U.S. National Arboretum, have been instrumental in the development of modern cultivars that have the typical lengthy flowering period during the summer months and a diversity of flower colors as well as disease (powdery mildew) resistance, cold-hardiness, showy exfoliating bark, and a range of sizes (from 40 cm to greater than 6 m) and growth habits (Pooler, 2003; 2006b). All these traits have led to a wide distribution and use of crape myrtles throughout southeastern U.S. gardens (Byers, 1997; Egolf and Andrick, 1978) and its categorization as a “naturalized” U.S. plant (Everett, 1981). Attesting to this status, in 1997, the common crape myrtle, L. indica, was designated as the official shrub for the state of Texas (Resolution 14, 75th Texas State Legislature).
The ruggedness and low-maintenance requirements of crape myrtles both in production and in the landscape have also been associated with relatively low insect and disease pressures. The very few insects that may regularly affect the appearance and performance of crape myrtles include aphids (Tinocallis kahawaluokalani Kirkaldy), Japanese beetle (Popillia japonica Newman), Florida wax scale (Ceroplastes floridensis Compsock), azalea bark scale Acanthococcus azaleae Comstock), and several species of flea beetles (Altica spp.) (Byers, 1997; Egolf and Andrick, 1978; Mizell and Knox, 1993). In recent years, there have been numerous reports by nursery growers of sudden and severe damage to young crape myrtle plantings by the Altica flea beetle with some reports of it becoming a serious pest in containerized nursery production throughout the southeastern United States (Braman and van de Mark, 2001; Pettis et al., 2004). A number of cultivated and weedy plants in the Oenothera, Calylophus, and Ludwigia (primrose) family and Lythracea (loostrife) family are the most common hosts for the primrose flea beetles (Altica litigata Fall) with both adults and larvae damaging the foliage in these plants (Center et al., 2002; McKenney, Reinert, and Cabrera, unpublished data; Schultz et al., 2001). However, only the adult flea beetles have become a pest on crape myrtles, where substantial populations of this insect can suddenly appear and severely damage and defoliate young and containerized plants (Byers, 1997; Pettis et al., 2004). To date, there have been only limited and anecdotal reports of extensive flea beetle damage to landscape-established crape myrtles.
We report on the differential resistance of containerized liners of crape myrtle species and cultivars to a severe attack of flea beetles in a nursery setting, which was followed by a no-choice feeding trial in the laboratory to verify flea beetle-feeding preference.
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