Parasitism rate of Trichogramma brassicae Bezdenko at laboratory conditions with six constant temperatures of 15, 20, 25, 30, 32 and 35±1oC, relative humidity of 65 ± 5% and a light period of 16 h. was evaluated on the eggs of gelechiid moth Sitotroga cerealella (Olivier). Parasitism rate of T. brassicae was significantly affected by different temperatures. The highest (40.257 hosts) and the lowest (3.731 hosts) values of net parasitism rate (C0) was obtained at 32 and 15oC, respectively. The transformation rate of host population to parasitoid offspring (Qp) was equal to 1 at all temperatures. The values of stable parasitism rate (y) increased from 0.074 to 0.451 (host/parasitoid) with increasing temperature from 15 to 30oC, but the values for this parameter at 32 and 35oC significantly decreased. The highest recorded value for finite parasitism rate (w) was obtained at 30oC (0.654 day-1). The temperature thresholds for finite parasitism rate of T. brassicae were estimated by nonlinear models of Briere-1 and Lactin-2. The Lactin-2 better fitted the related data (SSE=0.004833, R2adj=0.977, AIC=-38.7438). The obtained values for the lower temperature threshold (Tmin), optimum temperature (Topt) and upper temperature threshold (Tmax) of parasitism activity of this parasitoid were 13.20, 31.20 and 35.40oC, respectively.

Tomato leaf miner (Tuta absoluta) is one of the new and important pests of tomato in Iran and every year it reduces the yield and quality of the product in terms of marketability. Therefore, in order to use insecticides that are safer for the environment, consumers and natural enemies, in this study, the effect of spinosad, imidacloprid, indoxacarb and chlorantraniliprole insecticides on Tuta absoluta was evaluated under field conditions. This study was performed in a randomized complete block design with five treatments, one control, and three replications. The results of this study showed that the efficacy of chlorantraniliprole and spinosad was higher than indoxacarb and imidacloprid on the third, seventh, tenth and fourteenth days after spraying. Also, the effect of LC25 of each of the mentioned insecticides on the parasitism rate of tomato leaf miner moth eggs by two species of parasitoid wasps T. brassicae and Trichogramma evanescens was evaluated under laboratory conditions. The rate of reduction of parasitism in spinsad, imidacloprid, indoxacarb and chlorantraniliprole treatments for T. brassicae was 23. 73, 18. 31, 14. 58 and 9. 37%, respectively, and for T. evanescens 24. 02, 18. 65, 13. 78, 9. 75% was determined. The results showed that chlorantraniliprole was less toxic compared to other compounds studied for parasitoid wasps and compared to other insecticides, the rate of parasitism of two species of Trichogramma was less affected. Hence, its use in integrated pest management programs of T. absoluta is recommended.

The parasitic wasps Ooencyrtus telenomicida and Trissolcus grandis are among the most common biocontrol agents of the common sunn pest (CSP), Eurygaster integriceps. The Ooencyrtus spp. act as facultative hyperparasitoids of CSP eggs, which may earlier have parasitized by Scelionidae. The preference and choice of these wasps among hosts of different quality (recently deposited eggs, 2-, and 4d-old eggs, as well as recently parasitized CSP eggs by T. grandis, 3-, 7-, and 10 d-old parasitized eggs) was studied. The results indicated that, unexpectedly, parasitism rate was the highest in 4d-old eggs, while the wasps significantly avoided 10d-old parasitized eggs. The functional response experiments were carried out with the same set of hosts. The 72h-old inexperienced fertile females were confined individually with different host densities for 6h. The response of the wasp to all kinds of the host was a type III response. No response to 7d-old parasitized eggs was evident (non-significant parameters). Depending on the treatment, the highest parasitism rate occurred at densities 5 to 9 which was between 25.7 and 46.5%. The handling time and maximum attack rate ranged between 0.61 - 1.83 h and 3.27-9.85 host eggs respectively. The maximim parasitism rates was observed in the 10d-old parasitized eggs, newly deposited eggs and 4d-old eggs. The results of the functional response and host preference experiments were not confirming, and therefore more studies are still required to reveal the impact of host quality on the parasitoid.

Background: Intestinal parasites are of great importance in personal and social health. Intestinal parasitism has various prevalence in different cities, so the present study was carried out to determine the prevalence of intestinal parasitism in food-sellers in Sanandaj. Materials and methods: Between June and July 1997,260 food-sellers had been interviewed for this descriptive study. Stool examination was performed in three different time points and samples were studied by direct observation method.Results: The study population included 252 males and 8 females with mean age of 40.17±15.79 years. Intestinal parasitism was reported in 88 (33.8%) candidates, where the most common microorganisms were Ascaris (23.5%), Giardia (5.8%), Entamoeba Histolytica (1.9%), Entamoeba Coli (3.8%), Blastocystis Hominis (0.8%), Hymenolepsis nana (1.2%), and Trichocephalus (0.4%). 15-24 year-old individuals were more frequently affected, whereas those older than 44 years old had minor infection. There was no significant correlation between level of education and intestinal parasitism.Conclusion: Results have revealed high prevalence rate of intestinal parasitism specially ascariasis. Recognizing those affected individuals and promoting educational programs could be helpful.

For determination of percent parasitism of the aphid, Thelaxis suberi (Del Guercio) (Thelaxidae) parasitized by Adialytus thelaxis Stary (Aphidiidae), samples were taken from oak trees at four times in Abbas Abad, Behshahr, Mazandaran province, Iran during 1998-99. Sampls were taken randomly from cutted apical shoots having 10 centimeter length. Mummified aphids were counted carefully in the laboratory. Alive aphids were dissected under a stereomicroscope and parasitoid larvae were counted. Percentage of parasitied unmummified aphids (arcsine transformation) was plotted against percentage of mummified aphids (Mp) and the linear regression model of Nmˆ = - 0.82Mp + 57.3 was obtained. By incorporating estimated percentage of unmummified parasitism (Nmˆ) in model (2): Tp=Mp+ Nmˆ total percentage of parasitism (Tp) was estimated.Therefore, by means of these models it is not necessary to dissect aphids to determine percent parasitism. Total parasitism (Tp) could be estimated through determining merely the percent parasitism of mummified aphids.

Abstract. Trissolcus grandis Thompson (Hymenoptera: Scelionidae), a native Sunn pest egg parasitoid in Iran, has the potential as a biological control agent for sunn pest, Eurygaster integriceps Puton (Het.: Scutelleridae). However, its ecological characteristics have remained unclear. Thus, this study aimed to develop a parasitism model of T. grandis with sunn pest egg as host. In order to obtain the data for the model, the longevity, survivorship and parasitism capacity of the adult female T. grandis were examined at nine constant temperatures (15, 17. 5, 20, 25, 27. 5, 30, 32. 5, 35, and 37. 5±0. 5 °C), relative humidity 65 ± 5 % RH, and a photoperiod of 16: 8 (L: D) h. Longevity (mean±SE) decreased as temperature increased and was the longest at 15°C (73. 18±3. 86 days) and the shortest at 35°C (18. 98±0. 48 days). A modified model of Sharp-DeMichele well described adult developmental rate (1/mean longevity) in the range of studied temperatures (r2 = 0. 994) and was used to calculate the physiological age. The mean total host eggs parasitized/female (mean±SE) was greatest at 17. 5°C (275. 84 ± 3. 21 host eggs) and lowest at 15°C (25. 06 ± 3. 221 host eggs). The temperature-dependent total parasitism, the age-specific cumulative parasitism rate, and the age-specific survival rate were best described by an extreme value function (r2 = 0. 934), the two-parameter Weibull function (r2 = 0. 967), and a sigmoid function (r2 = 0. 979), respectively. I anticipate that the fitted models and parameters may be useful in developing a population model for T. grandis and lead to a better understanding of its parasitism strategy.

Eggs of grape leafhopper Arboridia kermanshah Delabola (Hem., Cicadellidae) are attacked by two parasitoid species Anagrus atomus L. (Hym., Mymariade) (species A) and Ufens sp. (Hym., Trichogramatidae) (species B) in Isfahan vineyards, Iran. For this research, 27 vineyards were selected randomly in different climatic regions of Isfahan. Ten plants were selected randomly per hectare of each vineyard and 3 leaves were sampled on each plant from lower, middle and upper strata. Then healthy and parasitized eggs were counted and the percentage of apparent parasitism was calculated in each vineyard. Three samples that each including 30 parasitized leafhoppers eggs were selected randomly from different climatic regions and the number of wasps were recorded. The percentage of marginal parasitism was calculated and compared for the two species. The average percentage of apparent parasitism in area of study was 8.33 that its range was varied at least 1.5 percent in very hot with dry desert up to 43 percent in dry temperate cold desert. The semi cold with warm and dry desert and semi-arid cold with dry desert climatic region with an average 82.8 percent had the highest percentage of marginal parasitism for species A and very hot with dry desert climate with an average 4.9 percent had the highest percentage of marginal parasitism for species B. The marginal parasitism of both species had moderate to high correlation with the percentage of apparent parasitism. The correlation coefficient of, in other words, the apparent parasitism was increased by increasing its marginal parasitism in climatic regions. While the correlation coefficient of species B was negative the apparent parasitism was decreased by increasing its marginal parasitism in climatic zones. Based on data obtained, it can be interfed that A. atomus was more efficient than Ufens sp. in different climatic regions of Isfahan province.