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Abstract
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Rhyncaphytoptus ficifoliae Keifer (Trombidiformes; Diptilomiopidae) is the main pest of fig trees in south and southwestern
regions of Iran. The effects of temperature on developmental time of R. ficifoliae were measured at constant
temperatures of 17, 20, 25, 30, 33 and 36 °C, with the relative humidity of 65 ± 5% and a photoperiod of 16: 8 (L: D) h
on fig leaves under laboratory conditions. According to results, R. ficifoliae successfully developed to adult stage at six
tested temperatures fed on fig leaves. The total developmental time (from egg to adult emergence) at above mentioned
temperatures was 21.62 ± 0.2, 15.02 ± 0.19, 10.05 ± 0.11, 7.77 ± 0.08, 6.02 ± 0.10 and 6.47 ± 0.16 days for females and
19.13 ± 0.17, 13.26 ± 0.18, 9.270.13, 6.91 ± 0.18, 5.65 ± 0.09 and 5.83 ± 0.19 days for males. The total developmental
rate of females increased as temperature increased from 17 to 33 °C, and then decreased at 36 ºC. Two linear and one
nonlinear models were fitted to developmental rate of immature stages to predict the developmental rate as a function of
temperature, as well as to estimate the thermal constant (k) and critical temperatures. Using the ordinary and Ikemoto and
Takai (2000) linear models the estimated lower temperature thresholds (Tmin) for total developmental time of females
were 10.78 and 10.37 °C and the constant temperatures (k) were 140.25 and 144.78 degree-days (DD), respectively. Also
the estimated low temperature at which an enzyme is half active (TL), intrinsic optimum temperature (TФ) and high
temperature at which an enzyme is half active (Th) for total immature stages of females by SSI model were 11.11, 23.72 and
37.98 °C, respectively. The highest (100%) and lowest values (51.67%) of survival rate for immature stages were found
at 25 and 36 °C, respectively. The presented information here could be used to predict the population dynamics of this
pest for an effective management.
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