BIOLOGICAL AND MICROBIAL CONTROL Sucrose Octanoate Toxicity to Brown Citrus Aphid (Homoptera: Aphididae) and the parasitoid Lysiphlebus testaceipes (Hymenoptera: Aphidiidae) C. L. MCKENZIE, 1 A. A. WEATHERSBEE III, 1 WAYNE B. HUNTER, 1 AND GARY J. PUTERKA 2 J. Econ. Entomol. 97(4): 1233Ð1238 (2004) ABSTRACT We report the toxicological effects of a new biorational, synthetic sucrose octanoate (AVA Chemical Ventures L.L.C., Portsmouth, NH), on brown citrus aphid, Toxoptera citricida (Kirkaldy), nymphs and adults and to its native parasitoid Lysiphlebus testaceipes (Cresson). Sucrose octanoate topically applied was equally toxic to brown citrus aphid adults and nymphs with LC 50 and LC 90 values ranging from 356 to 514 and 1029 to 1420 ppm, respectively. Mortalities of both stages did not differ signiÞcantly over time during the 3Ð24-h sampling period. Dry residues of sucrose octanoate exhibited similar levels of toxicity to both nymphs and adults. Mortality ranged from 60 to 70% at 6,000 ppm 4 h after exposure. L. testaceipes was not harmed by treatments as high as 4,000 ppm of sucrose octanoate as long as the parasitoid had mummiÞed before treatment. Based on these results, sucrose octanoate would be a useful biorational in citrus integrated pest management programs. KEY WORDS suger ester, biorational, Toxoptera citricida BROWN CITRUS APHID, Toxoptera citricida (Kirkaldy), causes serious economic damage to citrus crops throughout the world, primarily as a vector of citrus tristeza closterovirus (CTV) (Bar-Joseph et al. 1989). Brown citrus aphid is an efÞcient vector of CTV (Yokomietal.1994),andalthoughaphidscanbekilled with insecticides, virus transmission may occur before death. As a result, large quantities of insecticides are currently used that are expensive to apply, and whose use raises concern over negative impacts to the crop ecosystem and human health. Brown citrus aphids feed on citrus and its close relatives. Once established, these aphids affect the same trees year after year, causing severe leaf curl during high populations and potentially spreading CTV to new plantings of citrus in the absence of any efÞcacious control measures. The heavy use of a single insecticide often leads to the rapid development of insecticide resistance, a major concern to growers. Imidacloprid, a systemic insecti- cide, is currently used against brown citrus aphid and whiteßies; however, whiteßy tolerance to imidaclo- prid has already been observed in Arizona and Spain afteronly4yrofuseintheÞeld(Cahilletal.1996)and more recently in Guatemala (Byrne et al. 2003). The potential to develop resistance has motivated our group to develop biorational control products for the management of brown citrus aphid. Plant compounds from glandular trichomes and their exudates have been shown to contain toxicants, repellents, and adherents for killing, repelling, and trapping insect pests (Johnson and Severson 1982, DimockandKennedy1983,Duffey1986,Waltersetal. 1990). Severson et al. (1985) demonstrated that ma- terials secreted by plant trichomes contained sugar esters,includingsucroseestersandglucoseesters,that provide wild tobacco, Nicotiana species, with resis- tancetoaphidsandthataretoxictothetobaccoaphid, Myzus nicotianae Blackman (Severson et al. 1991, Xia et al. 1997); whiteßies (Buta et al. 1993); pear psylla, Cacopsylla pyricola Foerster (Puterka and Severson 1995); and other horticultural insect pests (Neal et al. 1994). For these reasons, we evaluated a synthetic analog of sucrose octanaote found in leaf trichomes of wild tobacco to determine its efÞcacy as a potential compound for use in an integrated pest management (IPM) program aimed at controlling brown citrus aphid in citrus, and to describe its potentially negative effects on Lysiphlebus testaceipes (Cresson), a native parasitoid of brown citrus aphid. Materials and Methods Insect Source and Rearing. Brown citrus aphids were collected in 1996 from Þeld populations infesting citrus near the USDAÐARS Research Laboratory at Orlando, FL, and used to start a laboratory colony. Insects used in the experiments were obtained from thisoriginalcolonyofbrowncitrusaphidthathasbeen Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that also may be suitable. 1 USDAÐARS, U.S. Horticultural Research Laboratory, 2001 South Rock Rd., Fort Pierce, FL 34945. 2 USDAÐARS, Appalachian Fruit Research Station, 45 Wiltshire Rd., Kearneysville, WV 25430 .