Abstract: The laboratory study at 28 ℃ showed that on four different corn cultivars,the durations of ovum,nymph and pre?oviposition,adult?longevity,fecundity,egg production per day,net reproductive rate (R0),finite rate of increase (λ),intrinsic rate of increase (rm),mean generation time (T),and the days needed to double population size (DDP) of Tetranychus truncatus were significantly different.The hatching rate on Zea mays cv.Zhongdan 2,Nongda 108,Chidan 202 and Badan 3 was 95.8%,94.0%,90.0% and 84.0%,and the survival rate on these cultivars was 90.5%,86.0%,84.0%,and 72.0%,respectively.All the survival curves were of Deevey Ⅰ.The net reproductive rate (R0) was the highest on Zhongdan 2,and the lowest on Badan 3.The mite displayed a decreasing preference in order of Zhongdan 2> Nongda 108> Chidan 202> Badan 3.

Key words: Rice, Free air CO₂ enrichment, Biomass accumulation and partition, Soluble carbohydrates, Leaf area index, Net assimilation rate