Pyrethroid insecticide residues on vegetable crops     

Ripley BD  Ritcey GM  Harris CR  Denommé MA  Brown PD 《Pest management science》2001,57(8):683-687

Pyrethroid insecticides were applied on various vegetable crops as foliar treatments to determine dissipation rates. On Chinese broccoli (Guy Lon), Chinese mustard (Pak Choi) and Chinese cabbage (Kasumi, napa), fenvalerate was persistent with residues of 0.10, 0.14 and 0.11 mg kg-1, respectively, by day 21. Cypermethrin residues on head lettuce were below 0.1 mg kg-1 by day 10 but on the leafier romaine and endive varieties it was more persistent and required 14-19 days to dissipate below this concentration. After three applications, residues of cypermethrin in harvested carrots and of permethrin in eggplant were not detected on the day of application. On asparagus, deltamethrin and cypermethrin residues declined to less than 0.1 mg kg-1 by days 1 and 2, respectively; permethrin was more persistent, requiring more than 2 days to decline to less than 0.1 mg kg-1. Deltamethrin on dry (cooking) and Spanish onions was not detected on the day of application. On tomatoes, the concentration of permethrin was 0.093 mg kg-1 on the day of application and declined to about 0.05 mg kg-1 after 2-4 days. In general, permethrin, cypermethrin and deltamethrin residues declined to acceptable concentrations within an acceptable pre-harvest interval. Fenvalerate may be too persistent on these speciality crops unless a maximum residue limit > 0.1 mg kg-1 is permitted.  相似文献   

Evaluation of uncalibrated preferential flow models against data for isoproturon movement to drains through a heavy clay soil     

Sabine Beulke  Colin D Brown  Igor G Dubus  Graham Harris 《Pest management science》2001,57(6):537-547

The uncalibrated predictive ability of four preferential flow models (CRACK‐NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK‐NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under‐estimated concentrations of isoproturon over a prolonged period in the first season and over‐estimated them in the two remaining seasons. CRACK‐NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 µg litre^?1, respectively, and matched the observed data (465, 65.1 and 0.65 µg litre^?1) slightly better than MACRO (69.1, 566 and 58.5 µg litre^?1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand‐alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 µg litre^?1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over‐estimated concentrations of isoproturon (967, 808 and 51.3 µg litre^?1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 µg litre^?1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils. © 2001 Society of Chemical Industry  相似文献   

Reviews section     

Dr Bill Symondson  W. O. C. Symondson  Dr Peter McEwen  Simon Oxley  Dr Patthumal Beevi  Houston Hobbs  Keith Harris  Dr R. T. Plumb  Professor P. G. Mantle  Professor J. Hemingway  Dr Barbara B. Shew  R. M. Baker  Professor P. A. Langley  David Dent 《Integrated Pest Management Reviews》1996,1(2):111-123

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Effect of sodium bicarbonate and sodium bentonite on digestion, solid and liquid flow, and ruminal fermentation characteristics of forage sorghum silage-based diets fed to steers     

K A Jacques  D E Axe  T R Harris  D L Harmon  K K Bolsen  D E Johnson 《Journal of animal science》1986,63(3):923-932

Six ruminally cannulated steers, five Holsteins and one Hereford (250 to 295 kg), were fed 84% forage sorghum silage plus 16% supplement or 50% forage sorghum silage plus concentrate and supplement diets containing either no addition (controls), 1% sodium bicarbonate (NaHCO3) or 2% sodium bentonite in a 2 X 3 factorial arrangement of treatments in a 6 X 6 Latin-square experiment with 3-wk periods. Sodium bicarbonate increased dry matter (DM) intake when concentrate was included, but neither compound affected intake of the 84% silage diet. Bentonite lowered DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibilities, but NDF disappearance from nylon bags was unchanged. Ruminal pH, osmolality and L(+) and D(-) lactate were not affected by treatment. Both NaHCO3 and bentonite tended to lower ruminal NH3-N concentrations. Bentonite lowered the molar proportion of isobutyrate in ruminal fluid relative to controls, but proportions of other volatile fatty acids (VFA) and total VFA concentrations were unchanged. Neither NaHCO3 nor bentonite affected ruminal liquid or solid volumes, dilution rate constants or ruminal outflow rates. Markers overestimated volumes, but correction with measured volumes did not change interpretation of treatment effects. It was concluded that control diets had sufficiently high baseline values of pH, dilution rate and acetate proportion to preclude changes induced by either compound, especially at 1 or 2% of DM intake. An effect on palatibility through neutralization of silage acids may have been responsible for the intake response to NaHCO3.  相似文献   

Effects of chilling on the formation of secondary growing-centres in flowers of the glasshouse carnation     

J.G. Atherton  G.P. Harris 《Scientia Horticulturae》1980,13(4):371-376

The incidence of secondary growing-centres within the flowers of carnation was increased when plants were chilled at 5°C for 1–3 weeks during flower development. Application of GA₃ to shoots in the early stages of flower formation also caused an increase in the number of secondary growing-centres formed. Shoot tips excised from plants that had been chilled yielded greater amounts of diffusible gibberellin-like substances than shoot tips excised from plants that had been grown at normal glasshouse temperatures. It is suggested that endogenous gibberellins have a role in controlling the formation of secondary growing-centres within the flower.  相似文献   

Visual detection of line segments: an object-superiority effect     

N Weisstein  C S Harris 《Science (New York, N.Y.)》1974,186(4165):752-755

Observers identified a briefly flashed line segment more accurately when it was part of a drawing that looked unitary and three-dimensional than when the line was in one of several less coherent flat designs.  相似文献   

Molluscicides for fluke control     

Harris RE  Charleston WA 《New Zealand veterinary journal》1972,20(1-2):12-13

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Primary hyperparathyroidism in a dog     

J W Wilson  S G Harris  W D Moore  H W Leipold 《Journal of the American Veterinary Medical Association》1974,164(9):942-946

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Intussusception in the cat     

M E Harris 《The Veterinary record》1968,83(23):597-598

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Treatment of dogs with oral melanoma by hypofractionated radiation therapy and platinum-based chemotherapy (1987-1997)   总被引：1，自引：0，他引：1  

Freeman KP  Hahn KA  Harris FD  King GK 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(1):96-101

This retrospective study in 39 dogs with incompletely resected oral melanoma examined the efficacy of hypofractionated radiation therapy and platinum-containing chemotherapy. All dogs were completely staged, with the majority of dogs classified as stage 1. Dogs received 6 weekly fractions of 6-gray (Gy) megavoltage irradiation with a cobalt-60 unit or a 4-MeV (megaelectron volts) linear accelerator. Dogs received cisplatin (10-30 mg/m2 IV) or carboplatin (90 mg/m2 IV) chemotherapy 60 minutes before radiation delivery. Durations of local control, metastasis-free survival time, and overall survival time were recorded. By the Kaplan-Meier method, 15% of the dogs had local recurrence within a median time of 139 days. Fifty-one percent of the dogs developed metastatic disease within a median time of 311 days (range, 24-2, 163 days). Median survival time for all 39 dogs was 363 days. The combined use of chemotherapy and radiation therapy in this protocol provided local control consistent with previous studies. Low-dose chemotherapy was used with the intent of enhancing radiation therapy for the local control of an incompletely excised tumor. Survival times were longer than previously reported for dogs with oral malignant melanoma. Additional studies are required to determine whether these results were due to the effects of chemotherapy on microscopic disease or the enhanced local control provided by chemoradiation therapy.  相似文献