Abstract
Methods of spatial analysis including distribution fitting, variance-to-mean ratios, Morisita's index, doublet and runs analyses, Greig-Smith analysis and variography were used to investigate the spatial pattern of hop downy mildew. Use of these methods allowed examination of the spatial structure of hop downy mildew at three spatial scales: within hop hills, between nearby hop hills, and for hop hills more separated in space. The results obtained were in general agreement for methods of analysis which assessed spatial structure at the same spatial scale with the exception of Morisita's index of clumping which did not identify clumps of diseased hills of the same size as Greig-Smith analysis and semi-variograms.
Keywords
spatial analysis, downy mildew, pattern, aggregation, dispersion.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Alldredge, J. Richard; Johnson, Dennis A.; and Allwine, Rochelle
(1989).
"COMPARISON OF HOP DOWNY MILDEW EPIDEMICS USING SPATIAL ANALYSIS,"
Conference on Applied Statistics in Agriculture.
https://doi.org/10.4148/2475-7772.1454
COMPARISON OF HOP DOWNY MILDEW EPIDEMICS USING SPATIAL ANALYSIS
Methods of spatial analysis including distribution fitting, variance-to-mean ratios, Morisita's index, doublet and runs analyses, Greig-Smith analysis and variography were used to investigate the spatial pattern of hop downy mildew. Use of these methods allowed examination of the spatial structure of hop downy mildew at three spatial scales: within hop hills, between nearby hop hills, and for hop hills more separated in space. The results obtained were in general agreement for methods of analysis which assessed spatial structure at the same spatial scale with the exception of Morisita's index of clumping which did not identify clumps of diseased hills of the same size as Greig-Smith analysis and semi-variograms.
