| Spatial distribution of Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on corn in Shahrekord |
| Paper ID : 1204-3IICE (R2) |
| Authors: |
|
َAnis Aboutalebian *1, Mostafa Haghani2, Habiballah Norbakhsh3, saeid bamdad4, Amirhossein Toorani5 1Ph.D. Student of Agricultural Entomology, University of Mohaghegh Ardabili, Ardabil, Iran 2Department of Plant Protection, Faculty of Agriculture, Yasouj University, Yasouj, Iran 3Associate Professor of Agricultural and Natural Resources Research Center, Chahar Mahal Va Bakhtiari, Shahrekord, Iran 4MSc student of Department of Plant Protection, Faculty of Agriculture, Yasouj University, Yasouj, Iran 5MSc graduated student in Agricultural Entomology, Department of Plant Protection, Faculty of Agricultural Sciences, Shahed University, Tehran, Iran |
| Abstract: |
| The bird cherry-oat aphid, Rhopalosiphum padi L. is a polyphagous pest of agriculture plants especially cereal as corn. In this study, three corn fields (2 ha) was studied in Chahartakhte agriculture research station in Shahrekord. Determine the sample size based on statistical calculations was carried with 20 samples. The sampling unit (bush), 120 samples from each field were selected randomly and weekly in the year 2011. The determination of spatial distribution was described by mathematical analyses: the variance to mean ratio (S2 / m) and Taylor’s power law, and Iwao’s regression. To calculate the ratio of variance to mean, all data collected on different dates were used altogether In the Taylor regression method Mean and variance related to each date after taking logarithms, the linear regression was obtained. The calculations were done using the Minitab software, and the results showed that the spatial distribution of alata aphids was randomized in all three fields (S2/x ̅ =1.11, 0.8, 1.12; ID=65.77, 47.2, 65.92; Z=0.56,-1.19, 0.57). In contrast, it was cumulative for apterous aphids in the same farms (S2/x ̅ =173.43, 258.54, 146.35; ID=1023.83, 152.54, 56.35; Z=132.15, 163.75, 120.51) with the variance to mean ratio. Using the Taylor method, the slope of the regression line (b) was greater than one. Therefore, the cumulative distribution of spatial distribution was confirmed (P=0.00, b=1.84, 1.96, 1.86 SE=0.10, 0.10, 1.36 R2=98.2, 98.2, 99.7 for apterous). However, for alata aphids, the regression between for data collected in the three studied farms was not significant (P> 0.05). Also, there was no significant difference between m and m * in the Iwao method for both alata and apterous aphids. Therefore, it was not possible to calculate the slope of the regression line. This results can be used to determine the sampling program and the IPM plan. |
| Keywords: |
| Rhopalosiphum padi, spatial distribution, Taylor, Iwao, Variance to mean ratio |
| Status : Paper Accepted (Poster Presentation) |
