PLANT RESISTANCE Evaluation of Vaccinium spp. for Illinoia pepperi (Hemiptera: Aphididae) Performance and Phenolic Content 1 CHRISTOPHER M. RANGER, JENNIFER JOHNSON-CICALESE, SRIDHAR POLAVARAPU, AND NICHOLI VORSA Philip E. Marucci Center for Blueberry and Cranberry Research and Extension, Rutgers, The State University of New Jersey, 125A Lake Oswego Road, Chatsworth, NJ 08019 J. Econ. Entomol. 99(4): 1474Ð1482 (2006) ABSTRACT Host acceptance and population parameters of the aphid Illinoia pepperi (MacGilli- vray) (Hemiptera: Aphididae) were measured on highbush blueberry, Vaccinium corymbosum L. ÔElliottÕ, and the wild species Vaccinium boreale Hall and Aalders, Vaccinium tenellum Aiton, Vaccinium pallidum Aiton, Vaccinium hirsutum Buckley, Vaccinium myrsinites Lamarck, and Vaccinium darrowi Camp. After 24 h of exposure, signiÞcantly fewer aphids remained in contact with V. boreale and V. hirsutum compared with V. corymbosum Elliott, V. darrowi, and V. pallidum. Length of the prere- productive period of I. pepperi was signiÞcantly longer on V. boreale and V. myrsinites, in contrast to V. corymbosum. Fecundity was also lower on V. boreale, V. hirsutum, V. myrsinites, and V. darrowi. Survivorship of I. pepperi 42 d after birth was signiÞcantly lower on V. hirsutum compared with the remaining Vaccinium spp. Reduced I. pepperi performance resulted in signiÞcantly lower intrinsic rate of increase (rm) values being associated with V. myrsinites, V. boreale, V. hirsutum, and V. darrowi, compared with V. corymbosum. Net reproductive rate (R0), generation time (T), and doubling time (Td)ofI. pepperi also were affected by the Vaccinium spp. Total phenolic and ßavonol content varied between Vaccinium spp., with some high phenolic content Vaccinium spp. having reduced aphid performance. However, no signiÞcant correlation between phenolics and I. pepperi performance was detected. Results from this study identiÞed several potential sources of aphid resistance traits in wild Vaccinium spp. KEY WORDS Illinoia pepperi, Vaccinium, blueberry, host suitability The aphid Illinoia pepperi (MacGillivray) (Hemi- Aphid-transmitted viruses have become a major ptera: Aphididae), is the most abundant aphid infest- threat to highbush blueberry production in New Jer- ing cultivated highbush blueberry, Vaccinium corym- sey and the PaciÞc Northwest. Since Þrst being de- bosum L., in the northeastern and upper Midwest of tected in the late 1970s, blueberry scorch virus the United States (Elsner and Kriegel 1989). I. pepperi (BlScV) has become one of the most economically is monoecious, spending its entire life cycle on Vac- important diseases affecting highbush blueberries on cinium spp. (Elsner 1982, Morimoto and Ramsdell both the east and west coasts of the United States 1985). Consequently, although within-Þeld move- (Stretch 1983; Martin and Bristow 1988, 1995; Bristow ment of alate and apterae I. pepperi occurs, movement et al. 2000). BlScV belongs to the carlavirus group and outside of cultivated highbush blueberries is rare is transmitted in a nonpersistent manner (Hillman et (Elsner 1982, Morimoto and Ramsdell 1985). I. pepperi al. 1996). Because I. pepperi is the most abundant aphid also has been collected from wild V. corymbosum, infesting cultivated highbush blueberries in the north- Vaccinium angustifolium Aiton, and Vaccinium myr- eastern United States, it is recognized as the primary tilloides Michuax (Elsner and Kriegel 1989). The ho- vector of BlScV within this region (Hillman et al. 1996, locyclic life cycle of I. pepperi consists of overwinter- Bristow et al. 2000). ing eggs that hatch into wingless, parthenogenic The primary tactic currently used for reducing the fundatrices during the spring (Elsner and Kriegel spread of BlScV in conventionally grown blueberries 1989). Subsequent summer generations consist of is the use of insecticides to control aphid vectors, along alate or apterous virginoparae giving birth partheno- with rouging symptomatic plants. However, BlScV has genetically to live young. In the fall, sexual morphs of a latent period of 1Ð3 yr before symptoms manifest, apterous females and alate males are produced. and certain cultivars are asymptomatic (Bristow et al. 2000). As such, an infected plant could continue to 1 Current address: Application Technology Research Unit, USDAÐ serve as a source of inoculum. By using host plant ARS, 1680 Madison Ave., Wooster, OH 44691. resistance to reduce aphid population Þtness, trans- 0022-0493/06/1474Ð1482$04.00/0 ᭧ 2006 Entomological Society of America August 2006 RANGER ET AL.: Vaccinium RESISTANCE TO I. pepperi 1475 mission of the nonpersistent BlScV could potentially Table 1. Vaccinium spp. used for measuring behavioral and be reduced. For example, certain selections of peach, biological responses of I. pepperi Prunus persica (L.) Batsch, are highly resistant to both Selection ID Ploidy Species Source Myzus persicae (Sulzer) and Myzus varians (David- or cultivar level son). Transmission of nonpersistent plum pox virus is V. darrowi NJ88-06-46 2x Santa Rosa Co., FL reduced on certain aphid-resistant P. persica selections V. darrowi NJ88-09-04 2x Polk Co., FL (Massonie and Maison 1980). Additional examples of V. darrowi Fla 4B 2x Marion Co., FL reduced virus transmission on aphid-resistant cultivars V. tenellum NC83-09-15 2x Bladen Co., NC exist for maize, Zea mays L. (Milinko et al. 1983); V. pallidum NJ88-18-32 2x Ocean Co., NJ V. boreale NJ88-29-35 2x Cape Brenton, NS, Canada muskmelon, Cucumis melo L. (Lecoq et al. 1979), soy- V. myrsinites NC84-06a-04 4x Lake Co., FL bean, Glycine max (L.) Merr. (Gunasinghe et al. 1988); V. myrsinites NJ88-07-43 4x Highlands Co., FL tobacco, Nicotiana sp. (Gooding and Kennedy 1985); V. hirsutum NJ90-54-07 4x Graham Co., NC and watermelon, Citrullus lanatus (Thunb.) (Gray et V. corymbosum Elliott 4x USDA Breeding Program al. 1988). Extensive information currently exists on the levels Vaccinium of pathogen resistance exhibited by spp. rooted shoots from single parent plants for V. tenellum, and blueberry cultivars (Stretch and Ehlenfeldt 2000, V. pallidum, V. boreale, V. hirsutum, V. myrsinites Ehlenfeldt and Stretch 2001, Stretch et al. 2001), yet NC84-06a-04 and NJ88-07-43, and V. darrowi NJ88- to date only one published study has examined aphid 06-46, NJ88-09-04, and Fla 4B. Thus, with the excep- resistance. In a Michigan Þeld trial, densities of adult tion of V. corymbosum Elliott, all replicates of a par- I. pepperi were recorded on 16 highbush blueberry ticular Vaccinium spp. possessed the same genetic cultivars on two dates in 1980 and three in 1981 (Han- identity. After removal from the parent plants, rooted cock et al. 1982). SigniÞcantly fewer aphids were de- cuttings were placed in a sand:peat moss (1:1) mixture. tected on four of the 16 cultivars, indicating potential One-year old V. corymbosum Elliott plants were pur- sources of resistance. Wild Vaccinium spp. represent a valuable source of chased from DeGrandchampÕs blueberry farm (South Haven, MI). All plants were maintained in a green- useful genes for insect and disease resistance. In an Ϸ attempt to identify possible sources of aphid resistance house for 6 mo before their use in experiments. for introgression into highbush blueberry cultivars, we Osmocote 14Ð14-14 (NÐPÐK) (Scotts-Sierra Horticul- characterized host acceptance, developmental, repro- tural Products, Marysville, OH) was used as a con- ductive, and life table parameters of I. pepperi in re- trolled release fertilizer. sponse to seven Vaccinium spp. Because carbon-based Colony Maintenance. A colony of I. pepperi was defense mechanisms are associated with long-lived established by collecting several apterous virginop- woody perennials adapted to nutrient poor environ- arae during June 2004 from a commercial blueberry ments (Berryman 1988), total phenolic and ßavonol planting in Atlantic Co., NJ. Because the overall ob- content also was measured in each of the Vaccinium jective was to identify sources of resistance against I. spp. to determine whether such compounds were cor- pepperi, multiple clones were used to establish the related with aphid resistance. colony. Apterous I. pepperi were occasionally added to the colony to ensure the presence of multiple geno- types. Aphids were reared on excised shoots of V. Materials and Methods corymbosum Elliott conÞned to plastic rearing con- Plant Material. Seven Vaccinium spp. were used in tainers. Cages were changed weekly and plant mate- this study: V. darrowi Camp, V. tenellum Aiton, V. rial was added as needed. The colony was maintained pallidum Aiton, V. boreale Hall and Aalders, V. hirsu- in a laboratory under ßuorescent lights with a photo- tum Buckley, V. myrsinites Lamarck, and V. corymbo- period of 16:8 (L:D) h. sum L. A single accession was tested for each species, Aphid Host Acceptance. Settling behavior of I. pep- with the exception of three accessions being tested for peri was measured on seven Vaccinium spp.: V. tenel- V. darrowi (NJ88-06-46, NJ88-09-04, and Fla 4B) and lum, V. pallidum, V. boreale, V. hirsutum, V. darrowi two accessions for V. myrsinites (NC84-06a-04 and NJ88-09-04, V. myrsinites NJ88-07-43, and V. corym- NJ88-07-43) (Table 1). For V. corymbosum, the highly bosum Elliott (Table 1). Approximately 6 to 7 cm of a susceptible highbush cultivar Elliott was used. All of single intact shoot from each of the aforementioned the Vaccinium spp., except V. corymbosum, were col- Vaccinium spp. was positioned in an individual dialy- lected from wild populations (Table 1) and partly sis-tube cage (4 cm in diameter, 13 cm in length) comprise the Vaccinium germplasm collection at the (WardÕs National Science, Rochester, NY), which was Philip E. Marucci Center for Blueberry and Cranberry sealed at both ends by using split foam plugs. Cages Research and Extension, Rutgers University, Chats- contained only leaf and stem tissue in the vegetative worth, NJ. Collection of these Vaccinium spp. were state and were positioned on the plants 24 h before described by Bruederle and Vorsa (1994). The parent their use in experiments. Five recently emerged apter- plants are potted in a (1:1) sand:peat moss mixture and ous I.