There is a premium on having Neotyphodium germplasm available for temperate grass improvement programs because these fungal endophytes present opportunities for developing new grass–endophyte combinations for enhanced tolerance to abiotic and biotic stresses. Unfortunately, surveys have revealed a low incidence of Neotyphodium fungi in grass germplasm collections. This research surveyed tall fescue (Festuca arundinacea Schreb.) accessions from a 1994 Australian–U.S. plant‐collection trip to Morocco, Tunisia, and Italy (Sardinia) for viable Neotyphodium fungi and determined whether infected accessions harbor different Neotyphodium genotypes. Conidial measurements of isolates cultured on agar and bioassays of the differential survival of bird cherry‐oat aphid [Rhopalosiphum padi (L.)] on infected accessions were used to characterize Neotyphodium diversity. A secondary objective determined the consistency of a polymerase chain reaction (PCR) method to detect Neotyphodium fungi in tall fescue. Neotyphodium was detected in 336 of 439 plants (76.5%) distributed among 104 accessions, of which 99 were endophyte‐infected. Mean conidial lengths of 42 isolates ranged from 3.91 to 9.91 μm. Most of the isolates (71.4%) had conidia with mean lengths smaller than the lower limit (6.5 μm) characteristic of the tall fescue endophyte N. coenophialum (Morgan‐Jones and Gams) Glenn, Bacon, and Hanlin. In aphid assays, all endophyte‐free plants were susceptible to R. padi and all but two infected plants were resistant to this aphid. Thus, a Mediterranean plant‐collection trip secured diverse Neotyphodium endophytes in tall fescue for storage in seed banks, and a PCR assay detected Neotyphodium in tall fescue plants of diverse geographical origin.

Control of the black vine weevil, Otiorhynchus sulcatus (F.), with allelochemicals produced from glucosinolates may be possible; however, plant-derived isothiocyanates are not readily available for bioassays. Our objective was to predict the toxicity of plant-derived isothiocyanates using a model developed with commercially available compounds. Contact toxicities of 12 organic isothiocyanates were determined by dipping black vine weevil eggs into isothiocyanate solutions. Quantitative relationships between the molecular structure of the isothiocyanates and their toxicities were estimated by regressing lethal concentrations against the compound's respective physiochemical parameters. Isothiocyanate polarity (log octanol/water partition coefficient) had the most significant effect on observed toxicities, whereas electronic and steric characteristics were unimportant. Using this linear structure−activity relationship, we predict that the highest contact toxicities to black vine weevil eggs will result from glucosinolates producing isothiocyanates with higher numbers of carbon atoms or those bearing sulfinyl, thio, or aromatic moieties. Keywords: Glucosinolates; isothiocyanates; allelochemicals; Brassica spp.; soil fumigation

tents reduces yield, while feeding scars and holes on testa reduce the quality and marketability of pea seed. The pea weevil, Bruchus pisorum (L.) (Coleoptera: Bruchidae), isIn addition, weevil-damaged seed has lower germination one of the most intractable pest problems of cultivated pea, Pisum sativum L. The availability of resistant cultivars would give growers rates and is prone to structural weakening during harmore pest management options. Searches for plant resistance to pea vest (Brindley and Hinman, 1937; Baker, 1990). High weevil were expanded to the Pisum secondary gene pool (P. fulvum levels of weevil-infested seed have been reported in Sm.) because seed resistance had not been located in P. sativum and Australia (10.6 to 71.5%; Horne and Bailey, 1991), subspecies. The objectives of this study were to determine the extent Spain (12.2 to 25.7%;Marzo et al., 1997), and the USA of pod and seed resistance to pea weevil in P. fulvum, and to use the (up to 64%; Pesho et al., 1977; Bragg and Burns, 2000). life table format to characterize weevil stage-specific mortality and Worldwide, pea producers rely mainly on contact insurvivorship on different P. fulvum accessions. Mortality of first instar secticides to control adults in pea fields before females larvae on pods, mortality of all weevil stages within seed, adult emerlay eggs on pods (Horne and Bailey, 1991; O'Keeffe et gence from seed, and seed damage levels were quantified. In two al., 1992; Clement et al., 2000). However, timing chemigreenhouse trials, more larvae died (14 to 50% averages) on pods of P. fulvum accessions than on pods of 'Alaska 81' (6% average), and cal applications to coincide with female egg laying is mortality of first instar larvae entering seed of P. fulvum accessions difficult. More than one application may be required if averaged 83.7%. Seed damage ratings (1 ϭ feeding scar on seed testa, weevil invasions continue for 2 to 4 wk in a pea field 0-1% cotyledon tissue eaten, dead first instar larva; 5 ϭ extensive (Michael et al., 1990). The development and use of cultidamage, live adult) averaged Ͻ3.0 for 26 P. fulvum accessions, comvars with pod and seed resistance to B. pisorum would pared with mean ratings of 4.9 for Alaska 81. Using weevil mortality reduce control costs and provide an environmentally and survivorship values in life tables and adult emergence rates, entries safer option than contact insecticides for adult weevil were classified as susceptible (two controls and five accessions), modcontrol. erately resistant (14 accessions), and resistant (12 accessions). Antibio-Some P. sativum lines with the Np gene respond to sis resistance was based on the death of weevil larvae on pods and the presence of pea weevil eggs on pods by forming seed testa and cotyledon tissues. The results identify sources of natural weevil resistance in the Pisum genome (26 moderately resistant and Abbreviations: GRIN, Genetic Resources Information Network.

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The pea weevil, Bruchus pisorum (L.), is one of the most intractable pest problems of cultivated pea, Pisum sativum L., in the world. This study investigated the transfer of pea weevil resistance from two accessions (PI 595946, PI 343955) of wild pea, Pisum fulvum Sibth. & Sm., to interspecific populations derived from crossing these accessions with a weevil-susceptible pea cultivar (ÔAlaska 81Õ). Partial life tables characterized weevil stage-specific mortality and survivorship on parents and interspecific progeny in two glasshouse trials. Larval mortality rates on pods (F 3 plants) of several F 2:3 families were between 36.0% and 52.9%. These means were statistically similar to mean mortality rates on pods of resistant parents (45.4% and 46.2%), but significantly greater than mean rates on the susceptible parent (1.2% and 10.6%). Pod surface characteristics contributed to high neonate larval mortality on pods of resistant parents and interspecific progeny. Seed resistance was not broadly transferred to interspecific progeny [revealed by high weevil survivorship in seeds (means mostly >80%) and high seed damage ratings of 3-5 where ratings of 1-2 denote resistance (production of resistant seed averaged 4.2% to 22.8%)]. Estimates of total weevil mortality on pods and seeds of eight F 2:3 families were 50-70%. Thus, weevil resistance in the Pisum secondary gene pool can be transferred to interspecific progeny, thereby providing a potential avenue to develop weevil-resistant pea cultivars.

In conjunction with efforts to identify efficient insect pollinators for seed multiplication of cross-pollinated plant species stored and maintained by USDA-ARS Western Regional Plant Introduction Station (WRPIS), experiments were conducted to assess and compare the efficiency of the house fly, Musca domestica L. (Diptera: Muscidae), and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae), and different densities of each fly species, to pollinate leek, Allium ampeloprasum L., plant inventory (PI) accessions in field cages for seed yield maximization and high germination. Cages with flowering plants were exposed to 0 flies or stocked with 100, 250, and 500 M. domestica or C. vicina pupae per week for 6 (2002) and 7 (2004) wk. Seed yield (weight per cage) increased linearly as fly densities (C. vicina or M. domestica) increased from 0 to 500 pupae per week, with 500 fly cages averaging 340.7 g (C. vicina) and 70.5 g (M. domestica) of seed in 2002 (PI 368343) and 615.3 g (PI 168977) and 357.5 g (PI 368343) in 2004 when only the C. vicina was used. For 0, 100, and 250 fly cages, seed yields averaged between 2.3 and 175.3 g in 2002 and 10.7 and 273.1 g in 2004. Mean 100-seed weights between treatments ranged narrowly between 0.4 and 0.5 g in 2002 and 0.3 and 0.4 g in 2004, and germination rates of seed lots from "fly cages" were mostly > or =80% in both years. The C. vicina is an efficient and cost-effective pollinator ($388.97 for pupae and shipping, compared with $2,400 for honey bee, Apis mellifera L. [Hymenoptera: Apidae], nuclei) for caged leek accessions, with 250 and 500 C. vicina pupae per week required to produce sufficient seed (130 g) to fill an accession storage bag in the WRPIS gene bank.

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