Life history parameters of the Sunn pest, Eurygaster integriceps, held at four constant temperatures.

The Sunn-pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), is the most important insect pest of wheat and barley in Iran. A demographic study was carried out in order to determine the effect of temperature on life history parameters of the pest. Life tables were constructed at four constant temperatures: 22, 25, 27, and 30 ± 1° C using Mahdavi wheat kernels as food. Finite and intrinsic rates of population increase, gross and net reproductive rates, intrinsic rates of birth and death, generation time, doubling time, and lifetime female fecundity all varied significantly among temperatures. The intrinsic rate of natural increase, rm, increased linearly with temperature and was estimated to be 0.0126, 0.0381, 0.0541, and 0.0789 females/female/day, respectively, at the above-mentioned temperatures. Generation time ranged from 121 days at 22° C to 40 days at 30° C. Net replacement rate was significantly lower at 22° C than at other temperatures (4.6 vs. 22.2 to 25.8 females/female/generation). Lifetime female fecundity ranged from 123.1 at 22° C to 209.4 at 30° C. The thermal threshold for post-diapause pre-reproductive development was estimated to be 20 degrees C, and 66.8 degree-days were required for its completion.

Temperature-dependent development and temperature thresholds of codling moth (Lepidoptera: Tortricidae) in Iran.

Developmental rate models and biological parameters estimated from them, especially lower and upper temperature thresholds and optimal temperature, can help to forecast phenological events of codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), in apple orchards. We studied the developmental time of immature stages of codling moth at eight constant temperatures ranging from 10 to 35 degrees C and modeled their developmental rate as a function of temperature using 13 published nonlinear and 2 linear models. Data were fitted to developmental rate models and temperature thresholds and the optimal temperatures were estimated. The models were evaluated based on adjusted coefficient of determination (R(2)(adj)) and Akaike information criterion (AIC), in addition to coefficient of determination (R(2)) and residual sum of squares (RSS). The thermal constants were 79.80, 312.60, 232.03, and 615.32 DD for egg, larva, pupa, and overall immature stages of codling moth, respectively, using the Ikemoto and Takai linear model. The Ikemoto and Takai linear model estimated lower temperature thresholds as 9.97, 8.94, 10.04, and 9.63 degrees C for egg, larva, pupa, and overall immature stages, respectively. Among the nonlinear models, the third-order polynomial fit the data well. This model estimates optimal temperature accurately. Brière-1 and Brière-2 accurately estimated the lower and upper temperature thresholds considering model evaluation criteria and accuracy of estimations.