بررسي سطح زيان اقتصادي سن گندم در مزارع گندم ديم استان كرمانشاه

Study on economic injury level of Sunn pest (Eurygaster integriceps Put.) on wheat in rainfed regions of Kermanshah province

In order to determine the Economic Injury Level (EIL) of Sunn pest (Eurygaster integriceps) in the cereal fields, two groups of studies were carried out in three regions of Kermanshah province, namely Droofaraman, Mahidashi and Dizgaran. During two consecutive years (1996-1998), 25 fields were selected in above-mentioned regions. Investigation and sampling initiated as soon as the first migration of hibernating individuals to the cereal fields occurred, involving the determination and the evaluation of the injuries. Average density of hibernated adults has been found to be around 3.3 hugs per square meter. Each hibernated adult has proved to he able to destroy 61 central shoots along with 12,2 white heads, resulting in 126 kg yield reduction in one hectare. Ell, for the hibernated adults has been estimated to he 1.30 and 1.65 individuals per square meter in two consecutive years. The density of the progenies including the various stages of nymphs and the new adults has been found to he 30 per square meter. Each individual from new generation was able to infest 0.5% of kernels at the time of physiological seed maturity and 0.7 % at the traditional harvesting time. Ell, for the nymphs has been estimated to be 4 and 2.8 individuals per square meter at the physiological seed maturity and harvesting time respectively.