بررسي توانايي سن گندم در تطبيق مراحل زيستي خود بافنولوژي گياه ميزبان

Study of the Capability of Sunn Pest (Eurygaster integriceps) to Synchronize Life Span With the Phenological Stages of Wheat and Barley

The capability of Sunn pest to synchoronize its life span with the phenological stages of wheat and barley was evaluated in experimental field in Varamin Agricultural Research Station for two consecutive years (1996-1998). The experiments were carried out in the form of the two factors complete randomized block design with 3 replications. The first factor was sowing date and the second one was wheat and barley cultivars. Additional experiments carried out in the farmerʹs field conditions. The results are as follows: I . In barley field, Sunn pestʹs life cycle was completed 7-10 days earlier than that in the wheat fields and Sunn pest synchronized its life cycle with phenological stages of hosts. 2. In barley fields 75% of the pest population were able to complete their life cycle on harvesting time, but at the same time wheat plants were at the waxy stage and only 27% of the individuals were in adult stage. 3. At harvest the weight of males and females was found to be significantly higher in wheat than that in barley and a significant correlation of the weight of newly emerged adults with plant growth span. 4. The earliness of wheat did not significantly affect sunn pest population and adults weight reduction in barley fields could not affect the pest population because they can fly to neighbouring wheat fields and complete their feeding cycle. Therefore control of this pest in barley fields should not be overlooked.