Life History, Intrinsic Rate of Increase and Field Population Fluctuation of Tetranychus kanzawai Kishida on Four Cultivars of Tea (Camellia sinensis (L.) Kuntze )

• Main Authors: Kuo-An Chang, 張國安
• Other Authors: Chain-Ing Shih
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/14577677759414919217

碩士 === 國立中興大學 === 昆蟲學系 === 88 === Significant differences of developmental duration of immature, adult longevity, oviposition period, reproductivity and sex ratio of Tetranychus kanzawai Kishida (KSM) were demonstrated on 4 tea varieties, Szu-Ji Chuen, (SJC); TTES No. 12, (TTES-12); TTES No. 13, (TTES-13); and Chin-Shin Oolong, (CSO) under 26  2℃, 65  3% RH and 12L: 12D. Egg duration of KSM among 4 tea varieties are significantly different (4.4∼4.8 days) but not the duration of larvae, protonymphs and deutonymphs. The variety significantly influences the developmental duration that ranges from 14.6 to 20.7 days, so does the oviposition period and the reproduction rate of females but not the longevity. Sex ratio favors female (0.75∼0.94 : ♀♀/ (♀♀＋♂♂)). The daily reproduction rate is accordingly decreased to female age and the curve fluctuates in cycle. The longest reproduction period is found in SJC where the shortest in TTES-13. The intrinsic rate of increase (rm) and net reproductive rate (R0) of KSM were estimated by two sexual life table, the calculated rm and R0 on SJC (rm = 0.078；R0 = 8.810) is the largest that follows TTES-12 (rm = 0.069；R0 = 6.520), and the smallest on TTES-13 (rm = 0.005；R0 = 1.140) and CSO (rm = 0.008；R0 = 1.230). The KSM population needs 27.4 ∼37.5 days for a mean generation time (T). The curves of net maternity value (vx) show a similar result on favorable variety for KSM population increases that are indicated by rm and R0. Annual mean population densities of KSM on 4 varieties in the field falls between 17.03∼104.08 mites per 5 leaves and they are significantly different (CSO > TTES-12 > TTES-13 = SJC). The stage specific densities of KSM also show a similar difference in density level among the 4 varieties. The seasonal occurrences of high density of KSM are significant and they are in Dec. for CSO, March for SJC, Oct. for TTES-12 and June for TTES-13. While the low densities occur in Aug.∼Oct., temperature (F = 13.92, P = 0.001) and density of predatory mites Amblyseius womersleyi (Schicha) (F = 28.47, P = 0.001) significantly influence the population density of KSM but not the rainfall and relative humidity. The temperature and predatory mite are considered as the major components influencing the KSM with a total influence of 81% up among the variance. However, the influences of rainfall cooperating with temperature need further study due to its non-even effects on the KSM densities in winter and summer.