Investigation on economic threshold of Russian wheat aphid in wheat crop
2003
Nourbakhsh, Sayyed Habibollah | Rezvani, Ali | Taheri, Mahmoud
During 1999-2000 economic threshold of Duraphis noxia(mordvilko) was investigated . The experiments were carried out in form of randomized complete block design with 5 treatments and 3 replicates. In 1999 the treatments were four rate of contaminating wheat plants as, 1,2,3,5 percent and check plot. In 2000 the treatments were four rate of contaminating wheat plants as, 1,3,5,10 percent and check plot. The check plots were sprayed with Oxidimeton methyl every 10 days. Contaminating were carried out in two growth stages of wheat include tillering and stem elongation. The plots were visited weekly and number of infested plants was numbered. Yield per plot was determined after harvesting. The results of contamination in tillering stage in 1999 has no significant difference (f=2.286 and ل=0.132) but the result of contamination in stem elongation stage in this year has a significant difference (f= 6.389 and ل=0.002). In the second year the results of two stages has no significant difference (f=0.558 and ل=0.07) and (f= 0.083 and ل=0.986). Also the weight of 10000 seeds of the yield of each plot has no significant difference (f=1.288 and ل=0.084) in seco
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