Hostname: page-component-7479d7b7d-m9pkr Total loading time: 0 Render date: 2024-07-13T01:54:36.888Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of inoculum sources on the accuracy and precision of experiments testing different times of applying fungicides to control powdery mildew (Erysiphe graminis f.sp hordei on spring barley

Published online by Cambridge University Press:  27 March 2009

J. F. Jenkyn ,
A. D. Todd ,
A. Bainbridge  and
G. V. Dyke
J. F. Jenkyn
Affiliation:
lACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK
A. D. Todd
Affiliation:
lACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK
A. Bainbridge
Affiliation:
lACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK
G. V. Dyke
Affiliation:
lACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK
Get access Rights & Permissions [Opens in a new window]

Summary

Experiments on spring barley at Rothamsted over the years 1974–81 were used to study how sources of powdery mildew inoculum affected responses to fungicide sprays applied at different times. Reinfection of early-sprayed plots was generally faster where they were close to a potent source of inoculum than where they were not. Conversely, effects of sources on yield, although not always significant, occurred mainly in the later-sprayed plots. Sources thus had their most important effects before these later sprays were applied, and probably during the very early stages of the epidemic. This implies that if experiments are to approximate to fields, they should, initially, be part of a large, uniformly-susceptible area of crop.

Regression analyses showed that delaying the application of fungicide sprays after the optimum date caused smaller yield losses in plots near minimal sources of inoculum than in plots near more potent sources. There was no conclusive evidence for effects of inoculum sources on the optimum date to apply a fungicide spray but the tendency was for the optimum to become later as inoculum pressure increased.

Separating fungicide-treated plots with mildew-resistant barley resulted in larger treatment effects and smaller residual mean squares than where there was no separation. Judged by residual mean squares alone, precision was approximately doubled by separation.

Type
Crops and Soils
Information
The Journal of Agricultural Science , Volume 126 , Issue 3 , May 1996 , pp. 259 - 275
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Ainsley, A. E., Dyke, G. V. & Jenkyn, J. F. (1995). Interplot interference and nearest-neighbour analysis of field experiments. Journal of Agricultural Science, Cambridge 125, 1–9.CrossRefGoogle Scholar
Anon. (1976). Manual of Plant Growth Stage and Disease Assessment Keys. Ministry of Agriculture, Fisheries and Food, Agricultural Development and Advisory Service.Google Scholar
Bainbridge, A. & Jenkyn, J. F. (1976). Mildew reinfection in adjacent and separated plots of sprayed barley. Annals of Applied Biology 82, 477–484.Google Scholar
Bainbridge, A. & Stedman, O. J. (1979). Dispersal of Erysiphe graminis and Lycopodium clavatum spores near to the source in a barley crop. Annals of Applied Biology 91, 187–198.CrossRefGoogle Scholar
Carver, T. L. W. & Griffiths, E. (1981). Relationship between powdery mildew infection, green leaf area and grain yield of barley. Annals of Applied Biology 99, 255–266.Google Scholar
Christ, R. A. (1957). Control plots in experiments with fungicides. Commonwealth Phytopathological News 3, 54, 62.Google Scholar
Daamen, R. A. (1986). Measures of disease intensity in powdery mildew (Erysiphe graminis) of winter wheat. 1. Errors in estimating pustule number. Netherlands Journal of Plant Pathology 92, 197–206.CrossRefGoogle Scholar
Dyke, G. V. (1956). The effect of date of planting on the yield of potatoes. Journal of Agricultural Science, Cambridge 47, 122–128.CrossRefGoogle Scholar
James, W. C., Shih, C. S., Callbeck, L. C. & Hodgson, W. A. (1973). lnterplot interference in field experiments with late blight of potato (Phytophthora infestans). Phytopathology 63, 1269–1275.Google Scholar
James, W. C., Shih, C. S., Hodgson, W. A. & Callbeck, L. C. (1976). Representational errors due to interplot interference in field experiments with late blight of potato. Phytopathology 66, 695–700.Google Scholar
Jenkyn, J. F. (1974 a). A comparison of seasonal changes in deposition of spores of Erysiphe graminis on different trapping surfaces. Annals of Applied Biology 76, 257–267.Google Scholar
Jenkyn, J. F. (1974 b). Effects of mildew on the growth and yield of spring barley: 1969–72. Annals of Applied Biology 78, 281–288.Google Scholar
Jenkyn, J. F. & Bainbridge, A. (1974). Disease gradients and small plot experiments on barley mildew. Annuals of Applied Biology 76, 269–279.Google Scholar
Jenkyn, J. F., Bainbridge, A., Dyke, G. V. & Todd, A. D. (1979). An investigation into inter-plot interactions, in experiments with mildew on barley, using balanced designs. Annals of Applied Biology 92, 11–28.CrossRefGoogle Scholar
Jenkyn, J. F., Dyke, G. V. & Todd, A. D. (1983). Effects of fungicide movement between plots in field experiments. Planl Pathology 32, 311–324.Google Scholar
Large, E. C. & Doling, D. A. (1962). The measurement of cereal mildew and its effect on yield. Plant Pathology 11, 47–57.Google Scholar
Roelfs, A. P., McVey, D. V., Long, D. L. & Rowell, J. B. (1972). Natural rust epidemics in wheat nurseries as affected by inoculum density. Plant Disease Reporter 56, 410–414.Google Scholar
Van der Plank, J. E. (1963). Plant Diseases: Epidemics and Control. London: Academic Press.Google Scholar
Zadoks, J. C., Chang, T. T. & Konzak, C. F. (1974). A decimal code for the growth stages of cereals. Weed Research 14, 415–421.CrossRefGoogle Scholar