Dose response of weeds to methyl iodide and methyl bromide   总被引：1，自引：0，他引：1  

W. M. ZHANG  M. E. McGIFFEN JR    J. O. BECKER  H. D. OHR  J. J. SIMS  R. L. KALLENBACH 《Weed Research》1997,37(3):181-189

Labonuory bioassay and field experiments were conducted to characterize the dose response of weeds to methyl iodide and methyl bromide as soil fumigants. The patterns in potency of both fumigants and in sensitivity of diffcretit weed species to the fumigants were distinguished with the use of logistic dose-response models. Similar to its response to methyl hromide fumigation. Amaranthus retrofleus L. was the most sensitive to methyl iodide fumigation. Cyperus rotundtis L. was the least sensitive to methyl iodide fumigation, whereas Portuloca oleracea L. was the least sensitive to methyl hromide. Lolium multiflorum Lam. Abutilon theophrasti Medik. Chenopodium album L. P. ateracea . Brassica kaber (D.C.) L.C. Wheeler and Cyperus escuden-tus L. were similar in sensitivity to methyl iodide. Methyl iodide was as potent as methyl bromide for A. retroflexus but more potent than methyl bromide for L. multiflorum , A. theophrasti. C. album. P. oleracea. B. kaber, C. esculentus and C. rotundus. The dose response for weeds in the field was similar to that obtained in laboratory bioassays. Under fieid conditions. 280 kg ha^-1 methyl iodide killed all species tested except Solanum nigrum L Methyl iodide appears to be a suitable replacement for meihyl bromide because it can be used in situations simitar to methyl bromide fumigation, has superior efficacy against a broad spectrum of pests and has a low potential for degrading the earth's ozone lavers.  相似文献   

Review: The strobilurin fungicides     

DW Bartlett  JM Clough  JR Godwin  AA Hall  M Hamer  B Parr‐Dobrzanski 《Pest management science》2004,60(3):309-309

The original article to which this Correction refers was published in Pest Management Science 58 (7): 649–662 (2002).Copyright © 2004 Society of Chemical Industry  相似文献   

Comparison of footbathing and vaccination to control ovine footrot in an experimentally infected flock          下载免费PDF全文

MB Allworth  JR Egerton 《Australian veterinary journal》2018,96(10):395-399

  相似文献   

Drivers,challenges and opportunities of forage technology adoption by smallholder cattle households in Cambodia     

K Ashley  S Wilson  JR Young  HP Chan  S Vitou  S Suon  PA Windsor  RD Bush 《Tropical animal health and production》2018,50(1):63-73

Forage technology has been successfully introduced into smallholder cattle systems in Cambodia as an alternative feed source to the traditional rice straw and native pastures, improving animal nutrition and reducing labour requirements of feeding cattle. Previous research has highlighted the positive impacts of forage technology including improved growth rates of cattle and household time savings. However, further research is required to understand the drivers, challenges and opportunities of forage technology for smallholder cattle households in Cambodia to facilitate widespread adoption and identify areas for further improvement. A survey of forage-growing households (n = 40) in July–September 2016 examined forage technology adoption experiences, including reasons for forage establishment, use of inputs and labour requirements of forage plot maintenance and use of forages (feeding, fattening, sale of grass or seedlings and silage). Time savings was reported as the main driver of forage adoption with household members spending approximately 1 h per day maintaining forages and feeding it to cattle. Water availability was reported as the main challenge to this activity. A small number of households also reported lack of labour, lack of fencing, competition from natural grasses, cost of irrigation and lack of experience as challenges to forage growing. Cattle fattening and sale of cut forage grass and seedlings was not found to be a widespread activity by interviewed households, with 25 and 10% of households reporting use of forages for these activities, respectively. Currently, opportunities exist for these households to better utilise forages through expansion of forage plots and cattle activities, although assistance is required to support these households in addressing current constraints, particularly availability of water, if the sustainability of this feed technology for smallholder cattle household is to be established in Cambodia.  相似文献   

Interactions between different media and follicle‐stimulating hormone supplementation on in vitro culture of preantral follicles enclosed in ovarian tissue derived from collared peccaries (Pecari tajacu Linneaus, 1758)          下载免费PDF全文

GL Lima  VB Luz  LF Lima  RMP Rocha  SV Castro  TS Castelo  APR Rodrigues  JR Figueiredo  AR Silva 《Reproduction in domestic animals》2018,53(4):880-888

The aim was to verify the effect of follicle‐stimulating hormone (FSH) supplementation to α‐MEM+ or TCM199+ media on the in vitro development of ovarian preantral follicles (PFs) derived from collared peccaries. Ovaries (n = 5 pairs) were collected and divided into fragments destined to control group (non‐cultured) or treatments that were cultured for 7 days. The PFs morphology, growth and activation were evaluated by classical histology. The immunohistochemistry markers Ag‐NOR and PCNA were used for nuclear proliferation analysis, and the picrosirius red labelling was used for ovarian extracellular matrix (ECM) evaluation. After 7‐day culture, only the TCM199+ treatment maintained the proportion of intact PFs similar to day 1 (63.2%), but no differences were found among treatments (p > .05). In addition, a significant increase in the growing follicles proportion was verified for all the treatments, indicating follicular activation (p > .05). By the Ag‐NOR analysis, only the TCM199+/FSH maintained the nuclear proliferation similar to the first day (p > .05). The picrosirius red staining revealed that the ECM remained intact in all the treatments (p > .05). We suggest the use of TCM199+ medium supplemented of FSH for the in vitro development of peccaries PFs under 7‐day culturing conditions.  相似文献   

Use of intralesional cisplatin to successfully treat distal limb haemangiosarcoma in a foal     

AM Norton  D McGilp  JR Vasey 《Australian veterinary journal》2023,101(8):308-312

A 4-month old, 200 kg, grey warmblood colt presented for a firm, non painful mass on the distal medial aspect of the left third metatarsus. Excisional biopsy revealed a diagnosis of haemangiosarcoma. Equine haemangiosarcoma is uncommon and only limited reports of successful treatment are available. The prognosis for survival is therefore considered to be poor. After two separate incidences of recurrence with incomplete excision of the tumour, intralesional treatment with cisplatin without excision or debulking was performed on three separate occasions. Intralesional cisplatin injection was performed at monthly intervals for three treatments. Four years post treatment with cisplatin, the horse remained in remission. This case report describes the diagnostic and treatment challenges for successful treatment of a primary haemangiosarcoma on the distal limb of a warmblood foal using intralesional cisplatin chemotherapy.  相似文献   

Association of double-stranded RNA with whitefly-mediated silvering in squash     

N. BHARATHAN  W. R. GRAVES  K. R. NARAYANAN  D. J. SCHUSTER†  H. H. BRYAN  R. T. McMILLAN JR 《Plant pathology》1990,39(3):530-538

A disorder of unknown aetiology appearing as silvering on squash (Cucurbita pepo) leaves has become prevalent in south Florida. Typical symptoms, observed after 2 weeks of exposure to adults of Bemisia tabaci , the sweet potato whitefly (SPWF) include vein clearing followed by silvering of whole leaves. Fruits from affected plants are blanched or streaked longitudinally. The silverleaf syndrome was not mechanically transmissible when crude extracts of symptomatic leaves were used as inoculum. Two sizes of double-stranded RNA (dsRNA) of c. 4.6 and 4.2 kilobase pairs (kbp) were consistently observed in leaf extracts of caged, whitefly-infested, symptomatic plants. In contrast, caged plants not exposed to whiteflies showed no symptoms and contained no detectable dsRN A. In addition, squash plants exposed to SPWF colonies from California neither developed silverleaf symptoms nor contained any dsRNA. Double-stranded RNA could also be readily detected in whitefly-infested yellow summer squash and zucchini from the field. However, asymptomatic eggplant and watermelon infested with SPWF from nearby fields did not contain detectable dsRNA. Dot-spot hybridization assays using an RNA-specific probe detected homologous sequences in both adults and nymphs of SPWF that induced silverleaf symptoms but not in adults and nymphs of SPWF that could not induce silverleaf symptoms. These results, along with the non-endogenous nature of the detected dsRNA suggest that the dsRNA is or is associated with the causal agent of whitefly-mediated leaf silvering in squash.  相似文献   

Pathogenesis studies with Australian bat lyssavirus in grey-headed flying foxes (Pteropus poliocephalus)     

McColl KA  Chamberlain T  Lunt RA  Newberry KM  Middleton D  Westbury HA 《Australian veterinary journal》2002,80(10):636-641

OBJECTIVE: To examine the susceptibility of the grey-headed flying fox (Pteropus poliocephalus) to Australian bat lyssavirus (ABL), and to provide preliminary observations on the pathogenesis of the disease in flying foxes. PROCEDURE: Ten flying foxes were inoculated intramuscularly with ABL, and four with a bat-associated rabies virus. Inoculated animals were observed daily, and clinical samples collected every 9 to 14 days. Animals with abnormal clinical signs were euthanased, and samples collected for histological, serological, virological and immunohistological examinations. At 3 months post inoculation (PI), all survivors were euthanased, and each submitted to a similar examination. RESULTS: Three ABL-inoculated flying foxes, and two rabies-inoculated animals developed abnormal clinical signs between 15 and 24 days PI. All three ABL-inoculated animals had histological lesions consistent with a lyssavirus infection, and lyssaviral antigen was identified in the central nervous system (CNS) of each. Virus was isolated from the brain of two affected animals. Of the rabies-inoculated flying foxes, both had histological lesions and viral antigen in the CNS. Virus was recovered from the brain of only one. None of the five affected flying foxes developed anti-lyssavirus antibodies, but, by 3 months PI, five of the seven ABL-inoculated survivors, and one of the two rabies virus-inoculated survivors, had seroconverted. The dynamics of the immune responses were quite variable. CONCLUSIONS: The response of flying foxes to ABL, administered by a peripheral route of inoculation, was similar to that of bats inoculated peripherally with bat-derived rabies viruses.  相似文献   

Production of insulin-like growth factor-I by granulosa cells but not thecal cells is hormonally responsive in cattle     

Spicer LJ  Chamberlain CS 《Journal of animal science》2000,78(11):2919-2926

To determine whether the hormonal regulation of IGF-I production differs between granulosa and thecal cells in cattle, granulosa and thecal cells from bovine follicles were collected, cultured for 2 d in medium containing 10% fetal calf serum, washed, and then treated for an additional 24 h in serum-free medium with various hormones. In Exp. 1, granulosa cells were treated with 0 or 100 ng/mL of insulin and(or) 50 ng/mL of follicle-stimulating hormone (FSH), insulin plus 10 ng/mL of epidermal growth factor, or insulin plus 10 ng/mL of basic fibroblast growth factor. In Exp. 2, thecal cells were treated as described in Exp. 1 except that 100 ng/mL of luteinizing hormone (LH) was used instead of 50 ng/mL of FSH. In Exp. 3, granulosa and thecal cells were treated with 0 or 30 ng/mL of cortisol with or without 100 ng/mL of insulin, 300 pg/mL of glucagon, or glucagon plus insulin. In Exp. 4, granulosa and thecal cells were treated with 0 or 300 ng/mL of estradiol with or without 100 ng/mL of insulin and(or) 100 ng/mL of LH. At the end of treatment, medium was collected, concentrated with Centricon-3 concentrators, and assayed for IGF-I by radioimmunoassay. Cell numbers were determined by Coulter counting at the end of culture. Thecal cells produced low amounts of IGFI (0.48 +/- 0.04, 0.63 +/- 0.03, and 0.82 +/- 0.03 ng per 100,000 cells per 24 h in Exp. 2, 3, and 4, respectively), and this production was not influenced (P > 0.05) by the various treatments. In contrast, IGF-I production by granulosa cells (2.0 to 6.2 ng per 100,000 cells per 24 h) was influenced by treatment in Exp. 1, 3, and 4 and was greater than IGF-I production by thecal cells (Exp. 2, 3, and 4). Alone, insulin, FSH, LH, and cortisol (but not estradiol) each decreased (P < 0.05) granulosa-cell IGF-I production by 20 to 57%; combined treatments of insulin plus FSH or insulin plus cortisol decreased IGF-I production to levels seen with insulin alone. Glucagon had no effect (P > 0.10) on IGF-I production in the absence or presence of insulin. In the presence of insulin, epidermal growth factor, basic fibroblast growth factor, and estradiol decreased (P < 0.05) IGF-I production below that observed for insulin alone. These results indicate that, during follicular development in cattle, changes in intrafollicular levels of IGF-I may be due to hormonally-induced changes in granulosa-cell, but not thecal-cell, IGF-I production.  相似文献   

Simulation study of the competitive ability of erect, semi-erect and prostrate cowpea (Vigna unguiculata) genotypes   总被引：1，自引：1，他引：1  

G WANG  ME MCGIFFEN JR  JL LINDQUIST†  JD EHLERS  & I SARTORATO‡ 《Weed Research》2007,47(2):129-139

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments.  相似文献