Binomial sampling plan of Metopolophium dirhodum in irrigated wheat fields

Binomial sampling plans was developed for monitoring Metopolophium dirhodum population in wheat fields of Varamin region, Iran. Aphid population was sampled weekly during two growing seasons of 2001-2002. In each sampling date, 50 wheat stems were chosen randomly and the number of aphids was counted and the data was used for developing binomial sampling plan. The results indicated that the sample size estimated from the binomial method was larger than the enumerative method at the density lower than one aphid per tiller. However, a larger sample size was required in enumerative method at higher aphid densities. Analysis of the linear regression between the observed and estimated proportions of wheat tillers infested with M. dirhodum showed good fit between the binomial model and the data. Applying the model, it was possible to estimate the mean aphid population densities observed in this study (0.02-20.18 aphid/tiller). The results revealed that the developed binomial sampling plan at precision levels of D= 0.25 (acceptable precision level in IPM) could be applied to reduce sampling time in monitoring programs of M. dirhodum in irrigated wheat fields of Varamin region.