Sequential sampling of the canola false chinch bug, Nysius cymoides (Hem.: Lygaeidae)

Crowds of the false chinch bugs Nysius cymoides appear in many canola fields of the country at pod ripening stage. To develop sequential sampling plans for eggs, immature stages and adults of the bug, samples were taken during two years from a canola field in the Broojerd Agricultural Research Station. Samples were randomly collected twice a week using a 5 × 5 cm quadrat and an aspirator. Then, the specimens were carried to the lab in alcohol tubes for counting the different stages. Taylor’s power law parameters were used to create Green’s sequential sampling plans at 10, 15 and 25 percent precision levels. The results showed that sample size for eggs was larger than nymphs and adults for different levels of precision. Sample sizes were dramatically reduced by increasing population density in different sequential models. Generally, sequential sampling models at 25 percent precision level are recommended for monitoring N. cymides populations due to reducing sample sizes to less than half, compared with those at 15 percent precision level. However, the 10 percent precision level models were not applicable because of large sample size estimations.