HORTSCIENCE 31(7):1219–1222. 1996. agement in New York (Eckenrode and Nyrop, 1995; Eckenrode and Webb, 1994). There is an urgent need to expand the range Variation in spp. Damage by of control options and to integrate them with still-effective chemicals. Rotation to Maggot non-allium crops for 1 year reduces OM popu- lations temporarily, but because adult OM James R. McFerson can travel several kilometers (Martinson U.S. Department of Agriculture, Agricultural Research Station, Plant Genetic et al., 1989), relatively large areas must be rotated for maximum effectiveness. Removal Resources Unit, Cornell University, Geneva, NY 14456-0462 of all bulbs from the field at harvest will Thomas W. Walters minimize food for overwintering OM popula- tions but does not prevent adult immigration Department of Fruit and Vegetable Science, Cornell University, Ithaca, from nearby sites the following spring. Addi- NY 14853-5904 tional control options might also help to avoid or delay development of resistance to insecti- Charles J. Eckenrode cides in OM populations. Department of Entomology, Cornell University, Geneva, NY 14456-0462 Plant resistance is an attractive but unexploited OM control strategy. Evaluations Additional index words. antiqua, , Allium ampeloprasum, plant resistance to of Allium germplasm for OM resistance have been reported from various regions (Ellis and Abstract. Nearly 350 germplasm accessions representing 25 Allium species were evaluated Eckenrode, 1979; Matthewman et al., 1953; for damage by onion maggot (OM) [Delia antiqua (Meigen)] in field experiments in 1989. McDonald et al., 1993a, 1993b; Perron et al., In 1990, 188 additional accessions and breeding lines were evaluated, and 36 entries from 1958; Scott and Franklin, 1972). Although the 1989 evaluation were re-evaluated. In both years, there were no significant differences some differences among A. cepa lines were in OM damage to seedlings among accessions within the species tested. However, differ- reported in these evaluations, A. cepa germ- ences among species were highly significant. Allium cepa L. (bulb onion) seedlings had plasm showed little evidence of variation for consistently high OM damage. Species with significantly less seedling damage than A. cepa resistance to OM in New York fields (Ellis et included: A. altaicum Pall., A. angulosum L., A. galanthum Kar. & Kir., A. pskemense B. al., 1979; Munger and Plage, 1974, 1975). Fedtsch., A. scorodoprasum L., A. ampeloprasum L. (leek), A. fistulosum L. (bunching However, bunching onion seedlings sustained onion), A. schoenoprasum L. (chive), and A. tuberosum Rottl. ex Spr. ( chive). Some low OM damage in New York (Ellis et al., species sustaining minimal damage as seedlings were nonetheless heavily damaged as 1979). mature plants by a later generation of OM. Allium cepa cultivars that were well-adapted The objectives of this research were to to local conditions were heavily damaged as seedlings, but their bulbs were less damaged evaluate Allium spp. injury levels from first- than those of poorly adapted A. cepa germplasm. Allium ampeloprasum seedlings and and third-generation (brood) OM in field plant- mature plants sustained low injury throughout both growing seasons. ings and to identify potential sources of resis- tance for onion breeding. We report here our survey of all Allium germplasm available in The onion maggot (OM) is a major pest of (A. fistulosum), garlic (A. sativum L.), leek (A. 1989–90 in the USDA–ARS collections, as onion and related crops in many temperate ampeloprasum), and chive (A. schoenoprasum) well as additional lines from the USDA–ARS regions of the world. Severe infestations can (Ellis and Eckenrode, 1979). and Univ. of Wisconsin onion breeding pro- destroy more than 50% of the seedlings in Each spring, gravid OM females lay eggs grams. Over 2 years, 535 Allium spp. acces- commercial fields when protection fails on or just under the soil surface near host sions and breeding lines were evaluated, in- (Eckenrode and Nyrop, 1995). In North seedlings. Larvae feed on the seedling bases cluding 380 A. cepa accessions and breeding America, the OM is particularly severe in New and roots, usually killing them. The first lines and 155 accessions of 24 other Allium York, Michigan, and Ontario, Canada, where above-ground symptom of OM injury on young species. conditions favor it and allium crops are grown plants is wilting. The whole plant subsequently in the same field or nearby fields year after collapses and dies. The most visible damage is Materials and Methods year. The host range of OM is limited to caused by first-generation larvae, which can and it has been reported on various destroy many young seedlings. Injury due to 1989 evaluation. A total of 365 entries economically important crops, including bulb second- and third-generation larvae, although representing 25 Allium species were planted onion and (A. cepa), bunching onion less visible above ground, is significant be- with a hand seeder in randomized complete cause damaged bulbs must be sorted out and blocks 20 to 21 Apr. in a commercial field near discarded after harvest (Ellis and Eckenrode, Potter, N.Y. (lat. 42°40’N, long. 77°0’W). Received for publication 29 Nov. 1995. Accepted 1979). Plots were 4.6 m long with two replications. for publication 9 July 1996. Mention of a vendor or Where are grown year after year in Seeding rates were adjusted to ≈30 viable proprietary product does not constitute a guarantee cool-season climates favoring OM develop- seeds/m. The center 1.5 m of each single-row or warranty of the product by the U.S. Dept. of Agriculture and does not imply its approval to the ment, an in-furrow insecticide application is plot containing the most even stand was marked exclusion of other products that also may be suit- essential. However, the has developed for subsequent stand and OM damage counts. able. This research was supported in part by funding resistance to insecticides, due in part to its Eighteen commercial cultivars of A. cepa were from the USDA–ARS, contract 58-43YK-9-0013, narrow host range, which maximizes selection used as treated controls and received an and by the New York State Onion Research and pressure for resistance to the few chemicals in-furrow insecticide application of Development Program. Onion breeding lines were used for OM management (Ellis and chlorpyrifos (Lorsban 15G; Dow Elanco, In- generously supplied by W.H. Gabelman, Univ. of Eckenrode, 1979). Thus, many compounds dianapolis, Ind.) at 1.4 g/4.6 m row. To mini- Wisconsin–Madison and M.J. Havey, USDA–ARS. recommended in the past have become inef- mize onion smut (Urocystis cepulae Frost), all Technical support was provided by the USDA–ARS fective (Harris and Svec, 1976; Harris et al., plots were treated with zinc ion and manga- Plant Genetic Resources Unit staff and by P.S. Robbins. The cost of publishing this paper was 1982). There is increasing evidence that the nese ethylene bisdithiocarbamate (mancozeb) defrayed in part by the payment of page charges. OM has developed low but significant levels (Dithane DF; Rohm and Haas, Philadelphia) Under postal regulations, this paper therefore must of resistance to O,O-diethyl-O-(3,5,6-trichloro- at the recommended rate of 0.6 g/4.6 m row. be hereby marked advertisement solely to indicate 2-pyridinyl) phosphorothioate (chloropyrifos), Cultural and other pest management practices this fact. the current insecticide of choice for OM man- followed commercial recommendations.

HORTSCIENCE, VOL. 31(7), DECEMBER 1996 1219 BREEDING, CULTIVARS, ROOTSTOCKS, & GERMPLASM RESOURCES

To determine initial plant populations be- had species and blocks as main effects and true extent and utility of their response to OM. fore serious OM injury occurred in the plots, transformed seedling loss and mature plant Significantly lower first-brood injury was mea- emerged seedlings were counted 2 to 5 June. damage as dependent variables. Species means sured in A. altaicum, A. angulosum, A. Plots infested with first-brood OM were as- were compared to the mean of the untreated A. galanthum, A. pskemense, A. scorodoprasum, sessed twice weekly, 2 June to 10 July. Plants cepa accessions using Dunnett’s comparison and in the cultivated species A. ampeloprasum, were considered damaged if they showed ob- with a control. Transformations and analyses A. fistulosum, A. schoenoprasum, and A. vious wilting. Damaged plants were removed were performed with JMP Version 3 Statisti- tuberosum. Other species (A. cernuum Roth, and examined for larvae to confirm OM at- cal Software for the Macintosh (SAS Institute, A. fuscoviolaceum Fomin, A. glaciale Vved., tack. In both years, infestations by first-brood Cary, N.C.). A. prostratum Trevir, and A. OM were uniformly heavy, allowing clear pseudoampeloprasum Miscz. ex Grossh.) sus- distinction between damaged and undamaged Results and Discussion tained even less first-brood injury, but the few plants during the ≈20,000 individual observa- entries within these species precluded statisti- tions throughout the season. Second-brood 1989 evaluations. Differences among spe- cal significance. Numerous accessions of A. OM injury was not evaluated. However, third- cies for both first-brood OM seedling loss and ampeloprasum (52), A. cepa (192), A. brood assessments were made 4 Oct. by re- third-brood OM mature plant damage (Table fistulosum (35), and A. schoenoprasum (17) moving up to 10 remaining plants per plot and 1) were highly significant (ANOVA, P ≤ were evaluated, but there was no significant examining their bases for naturally occurring 0.001). Block effects were also highly signifi- effect of accession within any of these species, larvae and feeding damage. Percent plants cant and the coefficient of variation was 37%. except for seedling loss within A. damaged was calculated from these assess- The physical extent of the experiment and an ampeloprasum (ANOVA, P ≤ 0.05). Insecti- ments. early season flood that retarded or killed plants cide treatments reduced first-brood injury in 1990 evaluations. Selected entries from in one block are possible explanations for this this test (50% in treated plots vs. 74% in the 1989 evaluation were re-evaluated in 1990, large variation, which reduced our ability to untreated plots), but not to commercially ac- with six replications and third-brood damage detect statistically significant differences ceptable levels. Flooding in May followed by levels enhanced by providing OM eggs from a among accessions. Seedling loss in untreated exceedingly dry soil conditions through July laboratory colony. A total of 36 entries repre- A. cepa was high (74%). Although there were may have reduced effectiveness of the insecti- senting four commonly cultivated species (A. no significant differences in seedling loss cide treatments. ampeloprasum, A. cepa, A. fistulosum, and A. among the A. cepa accessions, the range of Mature plant damage from third-brood OM schoenoprasum) were planted 24 to 27 Apr. in seedlings lost (22% to 100%, detailed data not feeding on untreated A. cepa was only 4%, a commercial field near Prattsburg, N.Y. (lat. shown) suggests that low or moderate resis- significantly less than the injury levels of 42°30’N, long. 77°15’W). Seeded rows were tance may exist within these A. cepa acces- some other species (Table 1). Intact mature A. 1.5 m long and later trimmed to 1-m plots in sions. The accessions within Allium Sect. Cepa cepa bulbs frequently are less damaged by randomized complete blocks. Insecticide- and A. ampeloprasum showing the lowest OM larvae than are immature plants treated and untreated plots of two commercial levels of first-brood OM damage (Table 2) are (Eckenrode and Nyrop, 1986; Finch et al., cultivars (Spartan Banner 80 and Buccaneer) of most interest for breeding purposes, but 1986). Like immature A. cepa, many of the were included as controls. Chlorpyrifos was further evaluation is necessary to clarify the non-bulbing Allium species evaluated lacked drenched into the seed furrow of treated con- trols at 0.15 ml/1.5 m row. Seedling emer- gence and first-brood OM damage were deter- mined 30 May and twice weekly, 30 May to 5 Table 1. Mean response of Allium spp. accessions evaluated in the field for onion maggot (OM) attack, July, respectively. Unless otherwise noted, Potter, N.Y., 1989. Response expressed as percent seedling loss (first-brood OM) and percent plants plot establishment, evaluations, and manage- damaged (third-brood OM). ment were as described for the 1989 evalua- Mean (%) tions. Seedling Mature plants To enhance uniform OM pressure on ma- Allium species No. accessions loss damaged ture plants, ≈250 eggs were applied to the soil albidum 18325 surface 10 to 14 Sept. next to five plants in altaicum 742* 12 each plot with sufficient surviving plants. Eggs ampeloprasum 52 39*** 9 were obtained from a laboratory colony estab- angulosum 324** 37* lished with larvae collected earlier in the year cepa 192 74 4 cepa (treated controls) 18 50*** NDz from nearby plantings and were flushed onto *** the soil surface with distilled water. Third- cernuum 1 24 100 dictyoprasum 25010 brood (percent plants damaged) evaluations fistulosum 35 49*** 2 were made 17 Oct. fuscoviolaceum 1650 In another 1990 experiment, 188 A. cepa galanthum 727*** 7 accessions and breeding lines from the USDA– glaciale 12 0 ARS and Univ. of Wisconsin breeding pro- ledebourianum 25148** grams, in which selection has taken place lineare 13740 under natural OM pressure, were compared obliqum 13340 with 12 insecticide-treated controls in four oreoprasum 1305 prostratum 1010 replications, using procedures described for pseudoampeloprasum 11415 the 1989 evaluation. pskemense 14* 20 Analysis. Seedling losses (first-brood OM pyrenacium 16060* damage) counts from each evaluation date ramosum 4449 were summed and divided by initial stand schoenoprasum 17 47** 55*** counts to calculate percent seedling loss for scorodoprasum 332* 32 each plot. Arcsin transformation of percent senescens 23645** seedling loss and of percent mature plant dam- tuberosum 45*** 21 age (third-brood OM damage) data was re- vavilovii 65420 quired to satisfy the normal distribution re- zND = no data. quirement for analysis of variance (Sokal and *, **, ***Seedling loss or mature plant damage significantly different from that of A. cepa accessions at P ≤ 0.05, Rohlf, 1981). Analyses of variance (ANOVA) 0.01, or 0.001, respectively, according to Dunnett’s comparison with a control.

1220 HORTSCIENCE, VOL. 31(7), DECEMBER 1996 protective dry outer scales. Likewise, under wheat (Triticum aestivum L.)/hessian Table 2. Accessions of Allium Section Cepa and A. our conditions of daylength and temperature, (Mayetiola destructor Say) (Buntin et al., ampeloprasum showing lowest percent seed- some of the A. cepa accessions did not bulb, 1992); wheat/greenbug (Schizaphis graminum ling loss to first-brood onion maggot attack in possibly altering their response to third-brood Rondani) (Porter et al., 1994); wheat/Russian field evaluations in Potter, N.Y., 1989. Number OM. Allium angulosum, A. cernuum, A. wheat aphid (Diuraphis noxia Mordvilko) of accessions tested per species indicated in parentheses. ledebourianum Roemer and Schultes, A. (Kindler et al., 1993); barley (Hordeum vulgare pyrenacium, A. schoenoprasum, and A. L.)/Russian wheat aphid (Webster et al., 1991); Allium accession Mean seedling loss (%) senescens L. all had significantly higher third- sorghum [Sorghum bicolor (L.) Moench]/ altaicum (7) brood injury than A. cepa. No third-brood greenbug (Andrews et al., 1993); maize/Euro- PI 483406z 31 injury measurements were made for treated A. pean cornborer (Ostrinia nubilalis Hübner) PI 280551 36 cepa since too few mature plants remained. (Reid et al., 1991), and carrot (Daucus carota PI 280552 38 The inconsistency between seedling loss and PI 369523 40 L.)/carrot rust fly (Psila rosae Fabricius) (Ellis PI 280549 45 mature plant damage suggests that resistance et al., 1993). While strong resistance within A. cepa (192) based on seedling data alone may not provide cepa would be highly useful to onion breeders, PI 262984 22 season-long protection. we found only moderate levels of resistance in PI 261768 25 1990 evaluations. As in 1989, the species certain accessions and differences among ac- PI 262921 28 effect on seedling loss and mature plant dam- cessions within a species were not statistically PI 275964 29 age was highly significant (ANOVA, P ≤ significant. Nevertheless, subsequent experi- PI 264315 35 0.001). Allium ampeloprasum, A. fistulosum, ments have demonstrated that these acces- PI 264225 35 A. schoenoprasum, and treated A. cepa again sions may have useable levels of resistance Dg11278 37 lost significantly fewer seedlings than untreated PI 249902 39 when combined with other management strat- PI 264323 41 A. cepa (Table 3). Commercially acceptable egies (Walters and Eckenrode, 1996). The PI 432714 41 levels of first-brood OM control were pro- resistance in related species may be difficult to fistulosum (35) vided by the chlorpyrifos treatments (12% exploit, given sterility barriers limiting suc- PI 462348 10 damage vs. 83% for the untreated plots). The cessful production of interspecific F1s. Such PI 280665 13 A. cepa accessions sustained much higher hybrids are highly male and female sterile, and PI 461393 16 mature plant damage than did the A. cepa their meiosis is abnormal (McCollum, 1971, PI 462359 20 accessions in 1989 (34% vs. 4%, respectively), 1982; Saini and Davis, 1967; van Raamsdonk PI 462355 22 probably because eggs from the laboratory et al., 1992). However, more intensive use of galanthum (7) colony were added in 1990 to increase infesta- conventional techniques, such as embryo res- C565 0 PI 280666 25 tion levels. In spite of the added eggs in 1990, cue (Gonzalez and Ford-Lloyd, 1987), as well PI 280565 27 control plots of two commercial A. cepa culti- as emerging molecular technologies, may even- PI 280566 33 vars adapted to New York growing conditions tually permit introgression by avoiding barri- PI 280091 38 sustained low third-brood injury levels (0% to ers to sexual recombination among Allium pskemense (1) 3%). These cultivars had already developed spp. Protoplast regeneration methods for A. PI 280577 4 protective dry outer scales by the time eggs ampeloprasum have been reported (Schum et vavilovii (6) were applied. In fact, two other well-adapted al., 1993) and might be applied to exploit first- PI 392509 27 cultivars (Norstar and Ruby) are suggested for and third-brood OM resistance in A. PI 406677 33 New York (Cornell Univ. Press, 1995) for low ampeloprasum through asexual hybridization. C567 63 C566 67 third-brood OM injury. Among species evalu- Related techniques could be applied to other PI 281727 68 ated in both years, only A. ampeloprasum had alliums as well. ampeloprasum (52) consistently low first- and third-brood injury, PI 255582 2 suggesting that this species has some resis- Literature Cited PI 256050 5 tance to first- and third-brood OM. PI 254535 5 A total of 188 untreated A. cepa accessions Andrews, D.J., P.J. Bramel-Cox, and G.E. Wilde. PI 296381 9 and breeding lines were evaluated in the sec- 1993. New sources of resistance to greenbug, PI 219900 13 Biotype I, in sorghum. Crop Sci. 33:198–199. z ond 1990 experiment. Seedling losses for the Buntin, G.D., S.L. Ott, and J.W. Johnson. 1992. PI = plant introduction. PI accessions supplied by untreated accessions in this planting averaged Integration of plant resistance, insecticides, and USDA–ARS germplasm collections, Geneva, N.Y., 83% compared to 21% in the 12 planting date for management of the Hessian fly and Pullman, Wash. Other accessions supplied by insecticide-treated controls. No third-brood (Diptera: Cecidomyiidae) in winter wheat. J. W.H. Gabelman, Univ. of Wisconsin–Madison and damage data were collected from this planting. Econ. Entomol. 85:530–538. M.J. Havey, USDA–ARS. There were no significant differences in seed- Cornell Univ. Press. 1995. Cornell pest manage- ling loss among the A. cepa accessions evalu- ated in 1989 or in the second 1990 experiment, but the range of seedling loss (1989 range 22% to 100%, 1990 range 47% to 100%) suggests that low or moderate resistance may exist Table 3. Allium spp. accessions evaluated for onion maggot (OM) damage, Prattsburg, N.Y., 1990 with mean within these accessions. As in 1989, block percent seedling loss (first-brood OM) and mean percent plants damaged (third-brood OM). effects for both 1990 experiments were highly Mean (%) significant, but CV values were lower, 20% and 19%, respectively. Nevertheless, more Allium Accessions Seedling Mature plants species evaluated (no.) loss damaged extensive testing is required to clarify the ampeloprasum 435*** 12* extent and utility of differences among acces- cepa cvs.—treatedz 212*** 3** sions. cepa cvs.—untreatedz 283NS 0* Our results are the first to demonstrate cepa—accessions 24 84 34 significant and consistent differences among a fistulosum 462*** 60* broad array of alliums for OM damage. This is schoenoprasum 439*** 37NS the first step in understanding and exploiting zTreated and untreated plots of A. cepa cvs. Spartan Banner 80 and Buccaneer were planted with and without genetic variation for host plant resistance to in-furrow insecticide, respectively. insect pests, as has been accomplished in a NS,*,**,*** Seedling loss or mature plant damage not significantly different, or significantly different at P ≤ 0.05, number of crop/pest interactions, including: 0.01, 0.001, respectively, according to Dunnett’s comparison with a control (A. cepa accessions mean).

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ment recommendations for vegetables and po- Harris, C.R. and H.J. Svec. 1976. Onion maggot results in testing for onion maggot resistance. tato production. Cornell Univ. Press, Ithaca, resistance to insecticides. J. Econ. Entomol. Veg. Improvement Nwsl. 16:4–6. N.Y. 69:617–620. Munger, H.M. and R.F. Plage. 1975. Further results Eckenrode, C.J. and J.P. Nyrop. 1986. Impact of Harris, C.R., J.H. Tolman, and H.J. Svec. 1982. in testing for onion maggot resistance. Veg. physical injury and commercial lifting on dam- Onion maggot (Diptera: ) resis- Improvement Nwsl. 17:4–5. age to onion bulbs by larvae of onion maggot tance to some insecticides following selection Perron, J.P., J. Jasmin, and J. Lafrance. 1958. Vari- (Diptera: Anthomyiidae). J. Econ. Entomol. with parathion or carbofuran. Can. Entomol. etal resistance of seeded onions to the onion 79:1606–1608. 114:681–685. maggot, Hylemya antiqua (Meig.) Eckenrode, C.J. and J.P. Nyrop. 1995. Onion mag- Kindler, S.D., K.B. Jensen, and T.L. Springer. 1993. (Anthomyiidae: Diptera). Can. Entomol. 90:654– got management in New York, Michigan, and An overview: Resistance to the Russian wheat 656. Wisconsin. New York Food & Life Sci. Bul. aphid (Homoptera: Aphididae) within the pe- Porter, D.R., J.A. Webster, and B. Friebe. 1994. 144. rennial Triticeae. J. Econ. Entomol. 86:1609– Inheritance of greenbug biotype G resistance in Eckenrode, C.J. and D.R. Webb. 1994. Onion insect 1618. wheat. Crop Sci. 34:625–628. Martinson, T.E., J.P. Nyrop, and C.J. Eckenrode. management in 1994. Proc. N.Y. State Veg. Reid, L.M., J.T. Arnason, C. Nozzolillo, and R.I. 1989. Long-range host-finding behavior and Conf. 103–104. Hamilton. 1991. Laboratory and field resistance colonization of onion fields by Delia antiqua Eigenbrode, S.D. and J.T. Trumble. 1994. Host to the European corn borer in maize germplasm. (Diptera: Anthomyiidae). J. Econ. Entomol. plant resistance to insects in integrated pest Crop Sci. 31:1496–1502. management in vegetable crops. J. Agri. Entomol. 82:1111–1120. Saini, S.S. and G.N. Davis. 1967. Compatibility in 11:201–224. Matthewman, W.G., J.P. Perron, and M.L. Cass. some Allium species. J. Amer. Soc. Hort. Sci. Ellis, P.R. and C.J. Eckenrode. 1979. Factors influ- 1953. Varietal responses of seeded onions to the 91:401–409. encing resistance in Allium sp. to onion maggot. onion maggot. Can. Entomol. 85:253–254. Bul. Entomol. Soc. Amer. 25:151–153. Maxwell, F.G. and P.R. Jennings. 1980. Breeding Schumm, A., L. Mattiesch, and A. Stoldt. 1993. Ellis, P.R., C.J. Eckenrode, and G.E. Harman. 1979. plants resistant to insects. John Wiley & Sons, Fundamentals for integration of cms into Allium Influence of onion cultivars and their microbial New York. porrum L. Allium Improvement Nwsl. 3:4–6 colonizers on resistance to onion maggot. J. McCollum, G.D. 1971. Sterility of some interspe- Scott, D.R. and D.F. Franklin. 1972. Apparent onion Econ. Entomol. 72:512–515. cific Allium hybrids. J. Amer. Soc. Hort. Sci. maggot resistance in some experimental onion Ellis, P.R., J.A. Hardman, T.C. Crowther, and P.L. 96:359–362. hybrids. Idaho Agri. Res. Prog. Rpt. No. 158. Saw. 1993. Exploitation of the resistance to McCollum, G.D. 1982. Experimental hybrids be- Sokal, R.R. and F.J. Rohlf. 1981. Biometry. 2nd ed. carrot fly in the wild carrot species Daucus tween Allium fistulosum and A. roylei. Bot. Gaz. W.H. Freeman and Co., San Francisco. capillifolius. Ann. Appl. Biol. 122:79–91. 143:238–242. Van Raamsdonk, L.W., W.W. Wietsma, and J.N. de Finch, S., M.E. Cadoux, C.J. Eckenrode, and T.D. McDonald, M.R., D. Fenik, and S. Janse. 1993a. Vries. 1992. Crossing experiments in Allium L. Spittler. 1986. Appraisal of current strategies for Research report #43: Muck vegetable cultivar section cepa. Bot. J. Linn. Soc. 109:293–303. controlling onion maggot (Diptera: trials and research reports. Ontario Ministry Walters, T.W. and C.J. Eckenrode. 1996. Integrated Anthomyiidae) in New York State. J. Econ. Agri. & Food. management of the onion maggot (Diptera: Entomol. 79:736–740. McDonald, M.R., S. Janse, and C. Anthomyideae). J. Econ. Entomol. (In press). Gonzalez, L.G. and B.V. Ford-Lloyd. 1987. Facilita- Bradley-MacMillan. 1993b. Research report #44: Webster, J.A., C.A. Baker, and D.R. Porter. 1991. tion of wide-crossing through embryo rescue and Muck vegetable cultivar trials and research re- Detection and mechanisms of Russian wheat pollen storage in interspecific hybridization of ports. Ontario Ministry Agri. & Food. aphid (Homoptera: Aphididae) resistance in cultivated Allium species. Plant Breed. 98:318–322. Munger, H.M. and R.F. Plage. 1974. Preliminary barley. J. Econ. Entomol. 84:669–673.

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