توسعه روش نمونه گیری دنباله ای در مدیریت تلفیقی سن گندم

The Sunn pest, Eurygaster integriceps Puton (Het.: Scutelleridae), has been identified as one of the most important insect pests of wheat and barley in Iran. Usually, based on some conventional methods, control measures are decided to prevent economical damages annually. Therefore, to improve the precision of control decision making, an effort was invested to develop practical methods for exact estimation of adult, nymph II and III densities in wheat fields of nine provinces during 2004-7. Dispersion indices and related statistics of the mentioned stages of Sunn pest were determined with 168, 176 and 183 data sets, respectively, which were finally used for designing sampling plans. Taylor's Power Law Regression was used to model the relationship between means and variances of each of stages data and Green's Constant Precision Sequential Sample Equation was used to develop sampling plans for different provinces. The results revealed that Sequential sampling method, on an average, required only 40 to 60 percent as many observations as an equally reliable fixed sampling procedure needed. Moreover, sequential sampling allowed the investigator to stop when a sufficient level of precision was reached. Besides, the new model would aid further research on Sunn pest population dynamics and also the relationship between pest density and yield. Finally, the obtained plan also can be used in tandem with recently developed economic thresholds for pest management decision making. Key Words: Sunn pest, Sequential sampling, Spatial distribution, Taylor's power law,Green's method.