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.

Age-specific life table parameters and survivorship, adult longevity, reproduction periods, fertility, and sex ratio of the codling moth were studied at eight constant temperatures (10, 14, 20, 25, 27, 30, 33, and 35 ±0.5°C). Among the examined temperatures, the highest values of net reproductive rate, intrinsic rate of increase, and finite rate of increase were 18.28 (females/female), 0.08 (females/female/d), and 1.08 at 27°C, respectively. Similarly, the highest value of sex ratio was 0.56 [females/ (females + males)] at 27°C. The highest mean generation time and doubling time were 72.26 and 23.09 d, respectively, at 20°C. To present a suitable model for intrinsic rate of increase at different temperatures, a nonlinear Lactin model was fitted to our observations. The longest preoviposition period was 2.77 and 2.55 d at 20 and 30°C, respectively. Also, the longest oviposition period was 8.46 d at 20°C. Postoviposition period was not statistically different at examined temperatures. The Weibull frequency distribution was used to describe the age-specific survival of the female adults. Based on the Weibull distribution parameters, the survival curves were type I at all examined temperatures, which indicates that mortality mostly occurred in old individuals. These findings confirmed that temperature is a critical environmental factor affecting codling moth population growth.

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° C, and 66.8 degree-days were required for its completion.

The Scelionidae were studied in some regions of Eastern Iran. In total 23 species from 7 genera were collected, among which two species, Eumicrosoma phaeax (Nixon, 1938) and Sparasion punctatissimum Kieffer, 1906, are new records for Iran.

Life table studies of sunn pest were carried out in Varamin, Iran, from 1998Iran, from -2001 in order to determine stage-specific mortalities and the impact of specific natural enemies on population dynamics. Populations were sampled 2-3 times weekly in agricultural fields during the growing season and monthly during the period of dormancy at resting sites in nearby mountains some 30 km away from cereal fields. Adults spend a period of 9-10 months in diapause and suffered overcompensatory, density-dependent mortality during this period. Variation in adult overwintering survival was inferred to be largely a function of the physiological condition of bugs that is reduced in a density-dependent manner by intraspecific competition for food among newly molted adults prior to migration to resting sites. Adult mortality emerged as the primary factor in key factor analysis, contributing 73% of the total variance in mortality. Other important factors were egg parasitism by Trissolcus vassilievi Mayr and adult parasitism by several species of Tachinidae. Although T. vassilievi made only a minor contribution to overall variance in total mortality, it had a significant effect on the number of newly molted adults, the life stage that is most damaging to cereal crops. The equilibrium level of the pest population in wheat fields was inferred to be ca. 72.6 adults m x2 , a number that substantially exceeds the economic threshold that ranges from 3-5 adults m x2 .