Efficiency of 1x1 meter quadrat for estimating of over-wintered adults of Eurygaster integriceps Put. (Hem., Scutelleridae) populations in rainfed wheat field

Subject Areas : entomology and othea arthropods

A.  Mohseni Amin ¹ (Member of academic board)

Received: 2009-10-05 Accepted : 2010-05-02 Published : 2010-08-23

Keywords:

Abstract :

This research was carried out to evaluate different aspects of one square meter quadrat size to estimate sunn pest over-wintered adults, Eurygaster integriceps Put.(Hem., Scutelleridae) in rainfed wheat field of Borujerd, north of Lorestan province, Iran, during 2003 and 2004. Iwao’s        regression had higher determination coefficients (r2=0.93) and showed a better fit as compared to r2 values calculated by Taylor’s power law (r2=0.86). Iwao’s patchiness regression slope (β=1.07±0.05) was not significantly larger than 1.0. Consequently, random dispersion pattern was determined for over-wintered adults in rainfed wheat fields. Therefore, Kuno’s fixed precision sequential sampling scheme based on Iwao’s parameters was constructed for overwintered adults of E. integriceps. An additional nine independent data sets, was used to validate the fixed-precision sequential sampling plans with resampling software of RVSP. Sample size curves indicated that estimating over-wintered adult population in rainfed field can be accomplished with a few sampling efforts when population is >2 insects per quadrat. For example only six samples need to be taken for the over-wintered adults, on average to achieve a precision of 0.25 (Dexp=0.25) when =3 insects per quadrat. However, sample sizes increase suddenly when population density is less than 0.3 insects per quadrat. Based on these results, 1*1m quadrat is not recommended to estimate number of over-wintered adults in rainfed wheat field.