Bragantia (2007) 66, 449-455

Leila Luci Dinardo-Miranda, Antonio Carlos Machado Vasconcelos, Sidney Rosa Veira, Juliano Vilela Fracasso and Célia Regina Grego (2007)
Uso da geoestatística na avaliação da distribuição de Mahanarva fimbriolata em cana-de-açúcar
[Use of geostatistics to evaluate Mahanarva fimbriolata spatial distribuition on sugarcane]
Bragantia 66 (3), 449-455
Abstract: Spatial distribution of Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) was studied in a 1,5 ha mechanically harvested green cane field, covering an area of 1.5ha, which was divided into 100 plots of 150 m² each. Seven evaluations of insect population were made between 24/11/2004 and 22/03/2005, which corresponds to the period of high infestation levels; insects were counted in the central row of each plot. The Morisita index was greater than 1 for all evaluations, indicating that the M. fimbriolata has aggregated spatial distribution and this pattern did not change over time and it was not affected by the infestation level. The geostatistical analysis allowed the construction of contour maps through kriging interpolation using the spatial dependence expressed in the semivariograms for the samplings made after 01/11/2005, when the insect was in second generation. The ranges varied from 33 to 53 m and, using this information, it was estimated that it was necessary to sample 3 points/ha to adequately estimate the insect population. At the beginning of the studied period, when the insect population was still low, it was not possible to construct population maps using kriging interpolation because the distance between sampling points was too large to detect spatial dependence. For this reason, it was concluded that for this period, more than 3 samples.ha^-1 would be necessary to estimate the insect population.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Database assignments for author(s): Leila Luci Dinardo-Miranda, Célia Regina Grego

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Mahanarva fimbriolata	Sugarcane (Saccharum officinarum)	Brazil (south)