Fixed-precision sequential sampling to estimate the population density of Heliothis viriplaca in bean fields of Shush District, Southwest Iran

The marbled clover Heliothis viriplaca is an important pest of beans and other legumes in many regions of the world. The development of precise and cost-benefit sampling methods plays a crucial role in the successful implementation of integrated pest management programs. The spatial distribution of H. viriplaca was investigated in a half-hectare research field in Amele-Seif County, Shush District, southwest Iran. Based on the data obtained, a fixed-precision sequential sampling plan was developed to estimate the population of this pest. The spatial distribution of these larvae on bean plants was evaluated using the Taylor and Iwao models. The spatial distribution of this pest on bean plants was found to be uniform, with the Taylor index providing a better fit for the spatial distribution data of larvae on the host plants. Therefore, Green’s model was used to develop a fixed-precision sequential sampling plan. To obtain the desired precision levels ۰.۱ or ۰.۲۵, the optimal sample sizes varied from ۲.۶ to ۵۷۶ or ۰.۴ to ۹۰ plants depending on the pest population density. Calculating the sampling stopping lines indicated that sampling for the pest should continue until the cumulative number of larvae on bean plants reaches ۰.۰۱۵ larvae when aiming for precision levels of ۰.۱ or ۰.۲۵.

کلیدواژه ها:

Green model ، Integrated Pest Management ، population estimation ، Spatial distribution ، sample size