Does shaking increase the pressure inside a bottle of champagne?

Colas, beers and sparkling wines are all concentrated solutions of carbon dioxide in aqueous solvents. Any such carbonated liquid is ordinarily conditioned inside a closed bottle or a metal can as a liquid-gas 2-phase system. At thermodynamic equilibrium, the partial pressure of carbon-dioxide in the gas phase and its concentration in the liquid are proportional (Henry's law). In practical conditions and use (transport, opening of the container, exterior temperature change, etc.), Henry's equilibrium can be perturbed. The goal of this paper is to describe and understand how the system responds to such perturbations and evolves towards a new equilibrium state. Formally, we investigate the dynamics around Henry's equilibrium of a closed system, through dedicated experiments and modeling. We focus on the response to a sudden pressure change and to mechanical shaking (the latter point inspired the article's title). Observations are rationalized through basic considerations including molecular diffusion, bubble dynamics (based on Epstein-Plesset theory) and chemi-convective hydrodynamic instabilities.

First Report of Soybean Cyst Nematode (Heterodera glycines Ichinohe) on Soybean in the Province of Quebec, Canada.

In eastern Canada, soybean, Glycine max (L.) Merr., is the most important legume, and its cultivation is expanding to new regions as cultivars for the short growing season are developed. The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is among the most destructive pests of soybean in the world. This nematode is also under quarantine regulations in many countries, including Canada. Until now, in Canada, SCN was only reported in the province of Ontario. Since its first detection in 1988 in the southwestern part of the province (1), SCN has been found in 12 other counties. It appears that SCN has been spreading in a north and northeast direction along the St. Lawrence River. We report here the first detection of SCN in the province of Quebec. Second stage juveniles (J2) and cysts were found in St. Anicet, Quebec, Canada, in a 10-ha soybean field. Light textured soil is a characteristic of the field, the same site where Pratylenchus alleni was recently discovered (2) and where irregular patches of stunted soybean plants were observed. Morphological and molecular studies of J2 and cysts confirmed the identification of this nematode population as SCN. The J2 were typical for SCN with a body length of 393 to 428 µm, lateral fields harboring four straight lines, a well-developed stylet 23 to 25 µm long, sub-ventral base knobs with posterior slops, a tail length of 43 to 50 µm, and a hyaline part of 23 to 29 µm. Cysts were brown and lemon-shaped with a posterior protuberance, ambifenestrated, underbridged, and had a strongly developed bullae. Key morphometrics were: a cyst fenestra 40 to 57 µm long and 28 to 44 µm wide, and a vulval slit 39 to 53 µm long. All of these are coincident with those of SCN (3). Ribosomal DNA of the ITS, 18S, and D2/D3 regions, and mitochondrial COX1 gene were PCR amplified from cysts and J2s gDNA using primers ITS-F (5'-TTGATTACGTCCCTGCCCTTT-3') and ITS-R (5'-ACGAGCCGAGTGATCCACCG-3'); 18S-F (5'-TTGGATAACTGTGGTTTAACTAG-3') and 18S-R (5'-ATTTCACCTCTCACGCAACA-3'); D2A (5'-ACAAGTACCGTGAGGGAAAGT-3') and D3B (5'-GACCCGTCTTGAAACACGGA-3'); and COXI-F (5'-CCTACTATGATTGGTGGTTTTGGTAATTG-3') and COX1-R (5'-GTAGCAGCAGTAAAATAAGCACG-3'), respectively, and sequenced. The nucleotide sequences were 98 to 100% similar to those of SCN found in NCBI nr database (July 2013). All the sequences have been submitted to GenBank with the following accession numbers: ITS (KF453621); 18S (KF453622); D2/D3 (KF453623); and COX1 (KF453624). Using species specific sequence characterized amplified region (SCAR) primers (4) also confirmed this was H. glycines. This is the first reported case of SCN in Quebec, Canada. The proximity of St. Anicet to the Ontario border is in accordance with the North/Northeastern dispersal hypothesis. The HG type of the SCN population will have to be determined before any resistant cultivars are deployed for the management of this pathogen in the province. References: (1) T. R. Anderson et al. Plant Dis. 72:453, 1988. (2) G. Bélair et al. Plant Dis. 97:292, 2013. (3) R. H. Mulvey. Can. J. Zool. 50:1277, 1972. (4) S. Ou et al. Nematology 10:397, 2008.

First Report of the Root-Lesion Nematode, Pratylenchus alleni Associated with Damage on Soybean in Quebec, Canada.

In eastern Canada, soybean, Glycine max (L.) Merr., is the most important cultivated legume species. In 2011, the provinces of Ontario and Quebec had 987,400 and 300,000 ha of soybean production, respectively. Root-lesion nematodes, Pratylenchus spp., are the most prevalent plant-parasitic nematodes in Canadian agroecosystems and can affect many crops (3). In 2011, irregular patches of stunted soybean plants were observed for the first time in a 10-ha soybean field grown on a light texture soil in St. Anicet, Quebec (45°4'50.51″N, 74°21'18.56″W). Yield reduction in damaged plots ranged from 38 to 54% when compared with asymptomatic adjacent plots. The field was sown with soybean cv. PRO 2715R (PRO Seeds of Canada, Woodstock, ON), a Roundup Ready cultivar of 2,750 CHU, at 100 kg/ha. Soil analysis revealed a uniform pH of 6.0 ± 0.2 on a gravelly sandy soil (81% sand, 10% loam, 9% clay, and 4% organic matter). On 7 October 2011, root samples were collected from 10 randomly selected damaged patches, washed under running water, and deposited in a mist chamber for a 14-day extraction period. Specimens were stored in tap water at 4°C before identification. Based on morphological characteristics, 26 individual specimens were examined (14 females, 11 males, one juvenile) and were all identified as Pratylenchus alleni Ferris, 1961 (2). Genomic DNA was extracted from individual larvae and the internal transcribed spacers (ITS) region was amplified. RFLP analysis with five restriction enzymes (CfoI, DdeI, HindIII, HpaII, and PstI) showed that the banding pattern for this species was different from those of 18 other major Pratylenchus species (4). Sequence of ITS regions of this population (GenBank Accession No. JX081545) confirmed genus identification but showed only limited homology (<85%) with the 20 Pratylenchus species available in the database at this time. Based on the morphological identification and the ITS sequence divergence with other important species, the sequence was deposited as the first P. alleni accession in GenBank. In the United States, the pathogenicity of P. alleni to soybean is well established (1). To our knowledge, this is the first report of P. alleni occurrence and damage to soybean in Canada. The outbreak of this root-lesion nematode will pose a new challenge for crop management since no registered compounds are currently available against this pest in soybean in Canada. References: (1) N. Acosta and R. B. Malek. J. Nematol. 13:6, 1981. (2) V. Ferris. Proc. Helminthological Soc. Washington 28:109, 1961. (3) J. W. Potter and A. W. McKeown. Can. J. Soil Sci. 83:289, 2003. (4) L. Waeyenberge et al. Nematol. 2:135, 2000.

First Report of Longidorus breviannulatus Associated with Damage on Creeping Bentgrass Golf Greens in Québec, Canada.

Creeping bentgrass, Agrostis stolonifera L., is the most important turfgrass species cultivated on golf greens in Canada. The needle nematode, Longidorus breviannulatus Norton & Hoffman, has several plant hosts including Gramineae such as corn, Zea mays L. (3), and creeping bentgrass (1). This large, plant-parasitic nematode is found most frequently in sandy soils and is encouraged by irrigation (2). In 2006, irregular, yellowish/chlorotic, and dead turfgrass patches were observed for the first time on several sand-based creeping bentgrass cv. Penncross greens on a golf course in Bromont, Québec (45°19'N, 72°39'W). Furthermore, a noticeable decline of the turfgrass root system was observed. Creeping bentgrass was grown with the following management practices: mowing height 3.18 mm, fertilization 2.27 kg N/0.45 kg P2O5/3.18 kg K2O/92.9 m2/year, aeration two times per year with 9.53-mm-diameter hollow core. On 5 July 2006, soil (0.5 kg) was sampled from two damaged areas of green no. 11. Three plugs (5-cm diameter × 15 cm deep) were taken from each area with a soil probe and pooled to form two separate samples. Another set of soil samples was collected on 12 July from three golf greens (nos. 10, 11, and 16). One sample was taken from each of three damaged areas and two healthy areas of each green. Plant-parasitic nematodes were extracted from 100-ml volumes of each soil sample by the Baermann pan and funnel extraction methods. Numbers of L. breviannulatus from the soil sampled on 5 July were counted with a stereo-microscope after 4 days of extraction, while numbers of L. breviannulatus in the rest of the samples were counted after 7 days of extraction. Identification was determined by morphological examination of a small number of adult female nematodes (n = 7). Characteristics distinguishing these specimens as L. breviannulatus include: amphidial pouches (bilobed and extending to the guiding ring), length 5,115 µm (4,780 to 6,230 µm), distance of the guiding ring from the oral aperture 26 µm (24 to 30 µm), odontostyle length 83 µm (78 to 90 µm), and tail length 42 µm (37 to 50 µm). In the two soil samples collected on 5 July, 0 and 183 juveniles per kilogram of dry soil were recovered with the Baermann pan method. In samples collected on 12 July from damaged areas of three greens, averages of 16 (min 0 and max 60) and 22 (min 0 and max 80) juveniles per kilogram of dry soil were obtained with the Baermann pan and funnel methods, respectively. No L. breviannulatus was found in any sample from healthy areas. Although no damage threshold has been established for L. breviannulatus in creeping bentgrass, low numbers of needle nematodes can be damaging in other crops such as corn. In our study, the occurrence of the damage was related to populations of the needle nematode, and therefore, the nematode was the likely cause of the damage. In Canada, L. breviannulatus is reported from Ontario (4). To our knowledge, this is the first report of the occurrence of L. breviannulatus in Québec. References: (1) L. B. Forer. Plant Dis. Rep. 61:712, 1977. (2) R. B. Malek et al. Plant Dis. 64:1110, 1980. (3) D. C. Norton and J. K. Hoffmann. J. Nematol. 7:168, 1975. (4) W. Ye and R. T. Robbins. J. Nematol. 36:220, 2004.

Reproduction of Pratylenchus penetrans on 24 Common Weeds in Potato Fields in Québec.

Twenty-four weeds commonly found in commercial potato fields in Quebec were evaluated for their host suitability to the root-lesion nematode, Pratylenchus penetrans, under greenhouse conditions. Brown mustard (Brassica juncea) and rye (Secale cereale) were included as susceptible controls and forage pearl millet hyb. CFPM 101 (Pennisetum glaucum) as a poor host. Pratylenchus penetrans multiplied well on 22 of the 24 weed species tested (Pf/Pi >/= rye or brown mustard). Cirsium arvense, Leucanthemum vulgare and Matricaria discoida were classified as very good hosts with a Pf/Pi ranging from 1.60 to 2.54, while Ambrosia artemisiifolia and Cyperus esculentus were classified as poor hosts with a Pf/Pi from 0.01 to 0.15. Amaranthus powellii, A. retrqflexus, Raphanus raphanistrum, Rorippa palustris, Cerastium fontanum, Spergula arvensis, Stellaria media, Chenopodium album, Vicia cracca, Elytrigia repens, Digitaria ischaemum, Echinochloa crusgalli, Panicum capillare, Setaria faberii, S. pumila, S. viridis, Polygonum convolvulus, P. scabrum and P. persicaria were intermediate hosts with Pf/Pi values ranging from 0.33 to 2.01. The plant species and the botanical family had a significant impact on nematode reproduction. The Brassicaceae family resulted in the greatest reproduction of P. penetrans, and the Cyperaceae resulted in the least. The plant life-cycle (annual vs. perennial) had no impact on nematode population.

First Report of the Barley Root-Knot Nematode Meloidogyne naasi Infecting Annual Bluegrass on a Golf Course in Quebec, Canada.

Annual bluegrass, Poa annua L., is an important component of the vegetation on golf course greens and fairways throughout Canada and is widely distributed across the world (2). The barley root-knot nematode, Meloidogyne naasi Franklin, infects and damages cereals such as barley (Hordeum vulgare), sorghum (Sorghum vulgare), and wheat (Triticum durum and T. vulgare), mainly in Europe. Of the root-knot species, M. naasi in particular, prefers grasses over other hosts, and infestations of this nematode can reduce the growth and vigor of turfgrasses (1). In July 2005, annual bluegrass at Beaconsfield Golf Club in Pointe Claire (45°26'N, 73°50'W), Quebec showed signs of an unidentified disease. Irregular yellowish/chlorotic patches were observed on the collar of one golf green. Lower turfgrass density in the turf areas with symptoms was noted. When roots were examined under a dissecting microscope, galling was observed. Upon dissection of washed galls, root-knot nematode egg masses and mature females inside the roots were observed. Nematode extractions of the soil from two samples of 50 g from the green and around the collar and perimeter were also done by the modified Baermann pan method. No juveniles were recovered from soil samples from the healthy area and an average of 400 and 1,500 juveniles/kg dry soil were counted in collar and perimeter samples of the patches. Morphological identification of mature females and juveniles were performed and confirmed to be M. naasi. Currently, there are no regulations to control the introduction of this nematode into Canada. To our knowledge, this is the first report of the occurrence of M. naasi in Canada where it is causing noticeable damage to turfgrass in Quebec. A soil survey is currently underway to examine the distribution of this nematode on golf course turfgrasses in Ontario and Quebec. References: (1) R. Cook and G. W. Yeates. Nematode pests of grassland and forage crops. Pages 305-350 in: Plant Parasitic Nematodes in Temperate Agriculture. K. Evans et al., eds. CAB International, Wallingford, UK, 1993. (2) S. I. Warwick. Can. J. Plant Sci. 59:1053, 1979.

First Report of Globodera tabacum Infecting Tobacco Plants in Quebec, Canada.

The tobacco cyst nematode Globodera tabacum (Lownsbery & Lowns-bery) Behrens is a damaging soilborne pathogen of shade and broadleaf tobacco in the United States (2). Nematode infection of roots can cause dramatic stunting, yield loss, and reduce leaf quality. G. tabacum is considered a complex of three cyst nematodes not distinguishable morphologically including G. tabacum tabacum, G. tabacum virginiae, and G. tabacum solanacearum. During 1998, infested flue-cured tobacco plants were harvested in the Lanaudière Region near Montreal, Quebec. Cysts recovered from roots and soil were identified by morphological and morphometric analysis of mature cysts and unhatched juveniles. Although multiple interceptions on nursery stock entering Quebec from infested nurseries in Hartford County, Connecticut from 1974 to 1986 have been recorded (1), to our knowledge, this is the first record of G. tabacum established in Canadian soil. On the basis of historic nematode infestations in this county, it could be inferred that it was G. tabacum tabacum, but further analysis is necessary for definitive subspecies determination. The infested tobacco plants were stunted in the field when compared with noninfested plants. Recently, the production in that area has been abandoned. Because cysts may survive for years in absence of host and also because potato, also a host of G. tabacum, is being introduced on these tobacco farms, it is believed that the distribution of this nematode could expand in the future in this part of the country. References: (1) Agriculture Canada Canadian Plant Quarantine Annual Reports. Intercepted Plant Pests. Publisher (Ottawa): Plant Protection Division, Department of Agriculture, 1967-2000. (2) J. G. Baldwin and M. Mundo-Ocampo. Heteroderinae, cyst- and non-cyst forming nematodes. Page 275 in: Manual of Agricultural Nematology. W. R. Nickle ed. Marcel Dekker Inc., New York, 1991.

Effect of Forage and Grain Pearl Millet on Pratylenchus penetrans and Potato Yields in Quebec.

Rotation crop experiments were conducted from 1998 to 2000 to assess the impact of forage and grain pearl millet (Pennisetum glaucum) on Pratylenchus penetrans populations in three potato (Solanum tuberosum cv. Superior) fields in Quebec. These crops were compared to oats and(or) barley. Forage millet had a suppressive effect on P. penetrans populations after a 1 year rotation. The following year, marketable potato yields were negatively correlated with initial P. penetrans densities on two experimental sites (r = -0.454, P = 0.044; r = -0.426, P = 0.017). Average marketable and total yields were increased by 10% in plots previously grown in forage millet hybrid CFPM 101 when compared to oats (P = 0.017). Damage functions between preplant nematode density (Pi) and marketable yield (y = 42.0 -4.091 log [Pi + 1]) and total yield (y = 43.9 -4.039 log [Pi + 1]) of potato were established on pooled yield data. Forage pearl millet is an efficient and economically viable alternative for managing root-lesion nematodes and improving potato yields in Quebec.

Efficacy of steinernematid nematodes against three insect pests of crucifers in quebec.

STEINERNEMATID NEMATODES WERE EVALUATED AGAINST THE THREE MAJOR CRUCIFEROUS INSECT PESTS: the imported cabbageworm Artogeia rapae, the diamondback moth Plutella xylostella, and the cabbage looper Trichoplusia ni. LC(50) values of S. carpocapsae All, S. feltiae UK, S. feltiae 27, and S. riobrave 335 were 18.2, 3.6, 5.7, and 8.3 on A. rapae L(2); 24.5, 2.3, 6.0, and 15.5 on P. xylostella L(3); and 10.1, 4.7, 9.5, and 7.8 on T. ni L(2), respectively. Insect mortality from the nematode species and isolates was modulated by temperature. Maximum mortality (100%) was recorded for A. rapae L(2) from S. riobrave at 30 degrees C, 95.8% from S. feltiae, and 91.7% from S. feltiae 27 at 25 degrees C and 75.7% from S. carpocapsae at 30 degrees C. Mortality of A. rapae L(2) increased with contact time to nematode. Mortality of 76% and 78% was achieved for S. carpocapsae and S. feltiae, respectively, after 12-hour exposure. Susceptibility of A. rapae, P. xylostella, and T. ni larvae to entomopathogenic nematodes increased with larval age development. The addition of adjuvants - Corn Oil (0.9%, 1.8%, 3.6%), Leafshield (3.0%, 6.0%, 12.0%), Seaweed (0.1%) and Agral (0.05%) - significantly increased the density and survival rate of S. carpocapsae on cabbage leaves compared to water only. At 20 degrees C and 70% relative humidity (RH), survival rates of S. carpocapsae All, S. feltiae UK, and S. riobrave 335 on cabbage leaves were 43%, 2%, and 0% after 4 hours following application. Under field conditions, foliar applications of S. carpocapsae provided 35.3% and 33.0% control of A. rapae (L(3)-L(5)) on Brussels sprouts and broccoli in 1996 and 24.9%, 19.4% and 14.9% on Brussels sprouts, broccoli, and cauliflower, respectively, in 1999. Based on our field results, foliar applications of S. carpocapsae do not provide an acceptable level of A. rapae control under Quebec's environmental conditions.

Susceptibility of the European chafer (coleoptera: scarabaeidae) to entomopathogenic nematodes (rhabditida: steinernematidae, heterorhabditidae).

The European chafer Rhizotrogus majalis (Razoumowsky) feeds on turfgrass roots, causing major damage in the urban areas of northeastern North America. A laboratory study was conducted to determine the susceptibility of third-instar chafer larvae to four species of entomopathogenic nematodes (Steinernema glaseri, S. feltiae, S. carpocapsae, and Heterorhabditis bacteriophora). Only S. glaseri was virulent, and only at high numbers (LD(50) = 294 nematodes/larva). Prolonged contact with nematodes increased host mortality. Optimal conditions for S. glaseri with respect to soil type and soil moisture were determined. Maximum larval mortality was obtained with 7% moisture and a 50/50 mixture of chernozem and sand. These results suggest that these nematodes currently have little potential for the biological control of the European chafer in turfgrass.

Retroperitoneal laparoscopic nephrectomy is safe and effective in obese patients: a comparative study of 55 procedures.

OBJECTIVES: To compare the results of retroperitoneal laparoscopic nephrectomy (RLN) in obese and nonobese patients, because various open surgical procedures have been reported to result in higher morbidity in obese patients. METHODS: Forty-eight consecutive patients underwent 55 RLNs in one center by one surgeon. Twenty-two patients were renal transplant recipients and underwent a total of 29 RLNs of the native kidney. Eight patients (9 procedures) were obese (body mass index 30 or more). The duration of the procedure, intraoperative and postoperative complications, and length of stay were compared between the obese and nonobese patients. RESULTS: The median operative duration was 100 and 70 minutes in the obese and nonobese patients, respectively. Three intraoperative complications occurred in nonobese patients. One postoperative complication (12. 5%) occurred in the obese patients; four (15.6%) occurred the nonobese patients. The median length of stay was 4 days for the obese and 3 days for the nonobese patients. The complication rate and postoperative length of stay were not significantly different between the two groups. CONCLUSIONS: RLN in obese patients was not associated with higher morbidity or longer hospitalization than in nonobese patients. We believe that RLN should be proposed to such patients when nephrectomy of a small nonfunctional kidney is indicated.

Foliar Sprays with Steinernema carpocapsae against Early-season Apple Pests.

Persistence and field efficacy of the entomopathogenic nematode Steinernema carpocapsae A11 strain applied by foliar sprays were evaluated against the apple sawfly Hoplocampa testudinea and the plum curculio Conotrachelus nenuphar, two early-season pests in Quebec apple orchards. From 1992 to 1995, bioassays with Galleria mellonella larvae were conducted to assess the persistence of S. carpocapsae on leaves, flower clusters, and twigs up to 4 days after evening application. S. carpocapsae juveniles remained infective on apple leaves 24, 42, 98, and 24 hours after application in 1992, 1993, 1994, and 1995, respectively. In bioassays, the percentage of G. mellonella mortality was consistently higher on leaves (average = 84%), intermediate on flower clusters (73%), and lower on twigs (43%) for all application dates. In 1992 and 1993, single nematode sprays applied every 2 to 3 days from early May to mid-June on apple tree limbs reduced primary damage caused by H. testudinea by 98% and 100%, respectively, but none of the treatments was effective in 1994. In 1993 and 1994, multiple border-row sprays were applied against C. nenuphar adults with a commercial hand-gun applicator in an insecticide-free orchard. At harvest, plum curculio damage in the nematode-treated orchard reached 5% and 55% in 1993 and 1994, respectively, as compared to 80% and 85% in an adjacent insecticide-free orchard. In a second experiment performed in 1994, multiple broadcast sprays with a commercial orchard sprayer caused no significant effect on plum curculio damage (nematode = 28%; control = 31%). Although some efficacy of canopy sprays of nematodes was detected against early-season apple pests, the inconsistent results and high application costs preclude their use as a sole control tactic against these pests in commercial apple orchards.

Retropubic cystourethropexy: is it an obstructive procedure?

PURPOSE: We sought to establish whether colpocystourethropexy creates bladder outlet obstruction, as evaluated by pressure-flow studies. MATERIALS AND METHODS: We retrospectively analyzed the records of 50 women. Preoperative evaluation included a detailed questionnaire, physical examination, urine culture, cystourethroscopy and multichannel urodynamic testing. Every patient underwent retropubic colpocystourethropexy according to the Tanagho modification of the original Burch technique. An average of 3 months after the operation clinical evaluation and identical multichannel urodynamic testing were repeated. Preoperative and postoperative urodynamic parameters were compared for each patient and statistical differences were established using Student's 2-tailed t test. RESULTS: No statistically significant difference was demonstrated in static urethral pressure profile parameters and in parameters during the filling phase of the cystometrogram except for cystometric capacity, which decreased after surgery (p = 0.02). In contrast, all 5 pressure-flow parameters analyzed (minimum urethral opening pressure, detrusor pressure at maximum flow, maximum flow, theoretical cross-sectional area and theoretical diameter of the flow rate controlling zone) showed statistically significant differences induced by surgery. Pressure-flow data reported on Schäfer's diagram and on the Abrams-Griffiths nomogram failed to demonstrate urodynamically significant obstruction created by surgery. CONCLUSIONS: Our data suggest that colpocystourethropexy does not create obstruction but, rather, restores pressure-flow conditions to a normal or nearly normal level.

Host Suitability of 32 Common Weeds to Meloidogyne hapla in Organic Soils of Southwestern Quebec.

Thirty-two weeds commonly found in the organic soils of southwestern Quebec were evaluated for host suitability to a local isolate of the northern root-knot nematode Meloidogyne hapla under greenhouse conditions. Galls were observed on the roots of 21 species. Sixteen of the 21 had a reproduction factor (Pf/Pi = final number of M. hapla eggs and juveniles per initial number of M. hapla juveniles per pot) higher than carrot (Pf/Pi = 0.37), the major host crop in this agricultural area. Tomato cv. Rutgers was also included as a susceptible host and had the highest Pf/Pi value of 13.7. Bidens cernua, B. frondosa, B. vulgata, Erysimum cheiranthoides, Eupatorium maculatum, Matricaria matricarioides, Polygonum scabrum, Thalictrum pubescens, Veronica agrestis, and Sium suave are new host records for M. hapla. Bidens cernua, B. frondosa, B. wulgata, D. carota, M. matricarioides, Pasticana sativa, P. scabrum, S. suave, and Thlaspi arvense sustained moderate to high galling by M. hapla and supported high M. hapla production (12.4 /= 2.9). Capsella bursa-pastoris, Chrysanthemum leucanthemum, Gnaphalium uliginosum, Stellaria media, and Veronica agrestis sustained moderate galling and supported moderate M. hapla reproduction (2.8 /= 0.5). Chenopodium album, C. glaucum, E. cheiranthoides, P. convolvulus, Portulaca oleracea, and Rorippa islandica supported low reproduction (0.25 /= 0.02) and sustained low galling. Galling was observed on Senecio vulgaris but no eggs or juveniles; thus, S. vulgaris may be useful as a trap plant. Eupatorium maculatum, and T. pubescens harbored no distinct galling but supported low to moderate M. hapla reproduction, respectively. Amaranthus retroflexus, Ambrosia artemisiifolia, Echinochloa crusgalli, Erigeron canadensis, Oenothera parviflora, Panicum capillare, Setaria glauca, S. viridis, and Solidago canadensis were nonhosts. Our results demonstrate the importance of adequate weed control in an integrated program for the management of M. hapla in organic soil.

Effects of Cropping Sequences on Population Densities of Meloidogyne hapla and Carrot Yield in Organic Soil.

The influence of various cropping sequences on population densities of Meloidogyne hapla and carrot yield was studied in organic soil under microplot-and field conditions. Spinach, radish, barley, oat, and wheat were poor or nonhosts for M. hapla. Population densities of M. hapla were maintained or increased on cabbage, celery, lettuce, leek, marigold, and potato. Marketable percent-age and root weight of carrots were greater following spinach, oat, radish, and fallow-onion than those following two crops of onion or carrot in microplots. Under field conditions, the carrot-onion-oat-carrot cropping sequence decreased M. hapla population densities and provided a 282% increase in marketable yield of carrot compared to a carrot monoculture. Two consecutive years of onion increased M. hapla population densities causing severe root galling and a 50% yield loss in the following crop of carrot. Based on root-gall indices, carrots could be grown economically for 2 years following radish, spinach, and oat, but not following onion and carrot without the use of nematicides.

Susceptibility of the Carrot Weevil (Coleoptera: Curculionidae) to Steinernema feltiae, S. bibionis, and Heterorhabditis heliothidis.

Larvae, pupae, and adults of the carrot weevil (Listronotus oregonensis) were infected and killed by the three entomophagous nematodes (Steinernema feltiae, S. bibionis, and Heterorhabditis heliothidis) under controlled conditions. Third-stage larvae were more susceptible than pupae or adults. S. feltiae and S. bibionis were the most aggressive nematode species, causing larval mortality after 24-48 hours in both continuous and 2-hour contact with nematode suspension. The nematodes multiplied sufficiently in all insects at all stages of development; however, production of infective-stage larvae per host cadaver was variable.

Nonfumigant Nematicides for Control of Root-knot Nematode to Protect Carrot Root Growth in Organic Soils.

Greenhouse tests were conducted to determine the effects of two kinds of Meloidogyne hapla inoculum on the growth and quality of carrot roots, and the protection afforded in each case by nonfumigant nematicides in organic soils. For all treatments the percentage of carrots damaged was greater with larvae alone as inoculum than with larvae and eggs, indicating that most of the damage occurs early during formation of the taproot. Fosthietan, aldicarb, and oxamyl at 4 and 6 kg ai/ha protected the roots during formation and gave a lasting control of root-knot nematode. There was some nematode damage to the roots with phenamiphos and carbofuran at 4 and 6 kg ai/ha. Isazophos, diflubenzuron, and fenvalerate gave little protection to carrot roots and did not control root-knot nematode effectively.