Spatial dispersion and sequential sampling plan for black bean aphid, Aphis fabae Scopoli, on faba bean fields in Veis region, Ahvaz

Black bean aphid, Aphis fabae Scopoli, is the most important pest of faba bean that causes economic damage on this crop. Spatial dispersion of the aphid using Taylor power law and Iwao patchiness indices were studied by weekly sampling in faba bean fields of Veis region, Ahwaz, during 2010-2012. Taylor's power law and Iwao patchiness were used to investigate spatial dispersion of A. fabae and a resampling for validation of sampling technique (RVSP) was used to develop a Green's fixed precision sequential sampling for this aphid population at precision levels of 0.25 and 0.1. Results showed that A. fabae had aggregation dispersion on faba bean and Taylor's power law had more fitness to the obtained data. Optimum sample size to estimate population density of A. fabae was ranged from 10 to 38 and 239 to 10 samples depend on population densities, at precision levels of 0.25 and 0.1, respectively.