caa a22 4500 386361053 CHVBK 20180307111915.0 cr unu---uuuuu 161130e198907 xx s 000 0 eng 10.4039/Ent121579-7 doi S0008347X00031837 pii (NATIONALLICENCE)cambridge-10.4039/Ent121579-7 Johnson D.L. Agriculture Canada Research Station, Lethbridge, Alberta, Canada T1J 4B1 SPATIAL AUTOCORRELATION, SPATIAL MODELING, AND IMPROVEMENTS IN GRASSHOPPER SURVEY METHODOLOGY [Elektronische Daten] [D.L. Johnson] Analysis of 10 years of grasshopper survey data (1978-1987) indicated that grasshopper populations in fields can be reliably predicted from roadside survey counts. Direct estimation of grasshopper densities in crop fields is no longer required for summaries of infestation levels or forecasts. Spatial autocorrelation was significant and positive for both roadside and field counts. The coefficient of variation of the field counts was greater than that of the roadside counts in each of the last 10 years. Population density was summarized by crop type and sampling method for the last 10 years. Linear regressions fitted to the 1978-1984 grasshopper survey data were used to estimate field population density from crop type and roadside counts in 1985-1987. Maps of population density were generated from the predicted and observed field counts with SPANS, a microcomputer-based geographic information system. Large coefficients of association (73-79%) between the predicted and observed maps attested to the sufficiency of road-side counts as the basis for production of population density maps. Copyright © Entomological Society of Canada 1989 The Canadian Entomologist Cambridge University Press 121/7(1989-07), 579-588 0008-347X 121:7<579 1989 121 TCE https://doi.org/10.4039/Ent121579-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.4039/Ent121579-7 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Johnson D.L. Agriculture Canada Research Station, Lethbridge, Alberta, Canada T1J 4B1 NATIONALLICENCE 773 0- The Canadian Entomologist Cambridge University Press 121/7(1989-07), 579-588 0008-347X 121:7<579 1989 121 TCE CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge