Tumours of Begonia and some other ornamentals,induced by Corynebacterium fascians

In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.     

Comparison of foliar and soil formulations of neonicotinoid insecticides for control of potato leafhopper, Empoasca fabae (Homoptera: Cicadellidae), in wine grapes

BACKGROUND: The potential of systemic neonicotinoid insecticides to control potato leafhopper, Empoasca fabae (Harris), a damaging pest of wine grapes in the eastern United States, was investigated. Soil or foliar applications were made to potted or field‐grown vines, and the response of leafhoppers was determined in clip cages over the following month on young or mature leaves. RESULTS: Foliar application of imidacloprid caused immediate and long‐lasting reductions in E. fabae survival on both leaf ages, whereas the activity of soil‐applied imidacloprid was delayed. Clothianidin, imidacloprid and thiamethoxam all provided long‐lasting reduction in leafhopper survival on young and mature foliage when applied through either delivery route. However, the percentage of moribund nymphs was significantly greater on foliar‐treated vines and increased over time in mature and immature leaves compared with soil‐treated vines. Residue analysis of foliar‐applied imidacloprid showed an 89% decline in mature leaves from day 1 to day 27, and a 98% decline in immature leaves over the same time period. Comparison of soil‐applied clothianidin, imidacloprid and thiamethoxam in field‐grown vines showed significant reduction in E. fabae only on mature leaves of vines treated with thiamethoxam. CONCLUSIONS: Neonicotinoids can control E. fabae in small vines, even in rapidly expanding foliage where this pest causes greatest injury. Soil application provides superior long‐term vine protection because declining residues on foliar‐treated vines lead to suboptimal activity within 2–3 weeks. Vineyard managers of susceptible cultivars may take advantage of this approach to E. fabae management by using foliar applications of the three neonicotinoids tested here, or by using soil‐applied thiamethoxam. Copyright © 2011 Society of Chemical Industry     

Bovine respiratory disease in feedlot cattle: phenotypic, environmental, and genetic correlations with growth, carcass, and longissimus muscle palatability traits

Bovine respiratory disease (BRD) is the most costly feedlot disease in the United States. Selection for disease resistance is one of several possible interventions to prevent or reduce the economic loss associated with animal disease and to improve animal welfare. Undesirable genetic relationships, however, may exist between production and disease resistance traits. The objectives of this study were to estimate the phenotypic, environmental, and genetic correlations of BRD with growth, carcass, and LM palatability traits. Health records on 18,112 feedlot cattle over a 15-yr period and slaughter data on 1,627 steers over a 4-yr period were analyzed with bivariate animal models. Traits included ADG, adjusted carcass fat thickness at the 12th rib, marbling score, LM area, weight of retail cuts, weight of fat trim, bone weight, Warner-Bratzler shear force, tenderness score, and juiciness score. The estimated heritability of BRD incidence was 0.08 +/- 0.01. Phenotypic, environmental, and genetic correlations of the observed traits with BRD ranged from -0.35 to 0.40, -0.36 to 0.55, and -0.42 to 0.20, respectively. Most correlations were low or negligible. The percentage of carcass bone had moderate genetic, phenotypic, and environmental correlations with BRD (-0.42, -0.35, and -0.36, respectively). Hot carcass weight and weight of retail cuts had moderate, undesirable phenotypic correlations with BRD (0.37 and 0.40, respectively). Correlations of BRD with LM palatability and ADG were not detected. Low or near zero estimates of genetic correlations infer that selection to reduce BRD in feedlot cattle would have negligible correlated responses on growth, carcass, and meat palatability traits or that selection for those traits will have little effect on BRD susceptibility or resistance.     

Differences between the ovine tonsils based on an immunohistochemical quantification of the lymphocyte subpopulations

In sheep, the pharyngeal first defence line against oral and inhaled antigens is organized in six tonsils. Since tonsils are regarded as secondary lymphoid tissue and part of the acquired immune system which is subjected to induction through contact with antigens, an evaluation of the different lymphocyte populations in tonsils is useful to determine a tendency of the specific tonsils to more inductive or more effective immunity. By means of immunohistochemistry, different lymphocyte populations were quantified and localized using a panel of eight antibodies, i.e. anti-CD45, anti-CD21, anti-CD2, anti-CD3, anti-CD4, anti-CD8, anti-WC1 and anti-Ki67. The CD21+ B lymphocytes were localized within the tonsillar lymphoid follicles. The CD2+/CD3+ T lymphocytes were numerous in the interfollicular regions and were aligned underneath and within the epithelium but were also observed at the CD21+ pole of the lymphoid follicles. Near the lingual and tubal tonsils, and the tonsil of the soft palate, the CD45+ cells around the seromucous glands and in the lamina propria were mainly CD3+ T cells. In all tonsils, the WC1+ gamma delta T cells formed a small lymphocyte population which harboured the lamina propria and the interfollicular region. The relative percentages of the different lymphocyte populations of the large palatine and pharyngeal tonsils, which are macroscopically the most developed, were comparable. In contrast, the lingual tonsil was significantly different from the other tonsils not only by its small size and lack of lymphoid follicles, but also by the lymphocyte populations. Based on the lymphocyte populations, the ovine tonsils can be divided in three groups with the tonsil of the soft palate, the tubal and paraepiglottic tonsil forming an intermediate between the palatine and pharyngeal tonsils as true tonsils on the one side, and the lingual tonsil as a scattered lymphocyte aggregation on the other side.     

Genetic analysis of carcass traits of steers adjusted to age, weight, or fat thickness slaughter endpoints

Carcass measurements from 1,664 steers from the Germ Plasm Utilization project at U.S. Meat Animal Research Center were used to estimate heritabilities (h(2)) of, and genetic correlations (r(g)) among, 14 carcass traits adjusted to different endpoints (age, carcass weight, and fat thickness): HCW (kg), dressing percent (DP), adjusted fat thickness (AFT, cm), LM area (LMA, cm(2)), KPH (%), marbling score (MS), yield grade (YG), predicted percentage of retail product (PRP), retail product weight (RPW, kg), fat weight (FW, kg), bone weight (BNW, kg), actual percentage retail product (RPP), fat percent (FP), and bone percent. Fixed effects in the model included breed group, feed energy level, dam age, birth year, significant (P < 0.05) interactions, covariate for days on feed, and the appropriate covariate for endpoint nested (except age) within breed group. Random effects in the model were additive genetic effect of animal and total maternal effect of dam. Parameters were estimated by REML. For some traits, estimates of h(2) and phenotypic variance changed with different endpoints. Estimates of h(2) for HCW, DP, RPW, and BNW at constant age, weight, or fat thickness were 0.27, -, and 0.41; 0.19, 0.26, and 0.18; 0.42, 0.32, and 0.50; and 0.43, 0.32, and 0.48, respectively. Magnitude and/or sign of r(g) also changed across endpoints for 54 of the 91 trait pairs. Estimates for HCW-LMA, AFT-RPW, LMA-YG, LMA-PRP, LMA-FW, LMA-RPP, and LMA-FP at constant age, weight, or fat thickness were 0.32, -, and 0.51; -0.26, -0.77, and -; -0.71, -0.89, and -0.66; 0.68, 0.85, and 0.63; -0.16, -0.51, and 0.22; 0.47, 0.57, and 0.27; and -0.44, -0.43, and -0.18, respectively. Fat thickness was highly correlated with YG (0.86 and 0.85 for common age and weight) and PRP (-0.85 and -0.82 for common age and weight), indicating that selection for decreased fat thickness would improve YG and PRP. Carcass quality, however, would be affected negatively because of moderate r(g) (0.34 and 0.35 for common age and weight) between MS and AFT. Estimates of h(2) and phenotypic variance indicate that enough genetic variation exists to change measures of carcass merit by direct selection. For some carcass traits, however, magnitude of change would depend on effect of endpoint on h(2) and phenotypic variance. Correlated responses to selection would differ depending on endpoint.     

Movement behaviour of large female yellow European eel (Anguilla anguilla L.) in a freshwater polder area

Due to a recruitment decline of more than 90% in 30 years, the European eel (Anguilla anguilla L.) has been classified by IUCN as critically endangered. Although the species has been studied intensively to obtain knowledge to improve management, studies about the resident yellow stage are relatively scarce. In this study, 52 large female yellow eels were tagged with acoustic transmitters in a Belgian polder system and tracked by a network of 23 automatic listening stations. We studied both circadian and seasonal movement patterns and the effect of environmental variables on these patterns. Large female yellow eels were most active at night in late summer and early autumn. A generalised linear mixed model showed that their movement is only slightly influenced by environmental variables. Moreover, as yellow eels show high site fidelity (i.e., the majority was detected only in the habitat type of their catch‐release location), they do not encounter many human‐induced connectivity problems in polder systems, which makes these systems highly suitable as eel growth habitat. These results can contribute to an effective eel management regarding habitat protection and restoration.     

Thieves,bats and fruit flies: local ecological knowledge on the weaver ant Oecophylla longinoda in relation to three ‘invisible’ intruders in orchards in Guinea

We held interviews with 100 mango and cashew growers in Guinea, West Africa. Fewer than 20 questions dealing with the tree-inhabiting weaver ant Oecophylla longinoda were developed, based on local context and related research conducted on farmers' knowledge in other countries. More than half of the growers reported that ants protect their orchard from thieves. Apart from deterring snakes, about 46% of the growers mentioned that weaver ants reduce damage by fruit-eating bats; some reported that bats do dislike the smell of weaver ants. Whereas the relationship between ants and humans or conspicuous fruit bats is well understood, a quantitative appreciation of the effect of Oecophylla on small insect pests, such as fruit flies, is more complex. Despite the fact that 57% of the growers reported that Oecophylla had a positive effect on mango fruit quality, many classified Oecophylla as a pest due to its nuisance during harvest, and they requested the plant protection staff to help them with pesticides. Strategies to strengthen local ecological knowledge are discussed.     

Population studies of the citrus psylla,trioza erytreae: factors influencing dispersal

More adults of the citrus psylla,Trioza erytreae (Del Guercio) (Hemiptera: Triozidae), dispersed when the number of eggs, nymphs or adults on the citrus increased (positive correlations) and also when new leaves that were present decreased (negative correlation). More psylla were trapped close to high obstacles than in an open area, even though the obstacles were at a distance from the psylla-infested orchard.