فهرست مطالب shahram shahrokhi khaneghah

Spatial distribution of the English grain aphid, Sitobion avenae (F.), was studied in wheat fields of Mahidasht, Kermanshah province and Sequential sampling models with fixed precision level were prepared for its monitoring. Sampling was conducted during five years. At each sampling date, 100 tillers were randomly visited. The mean range of population density in wheat field was 0.39-34.01 aphids/ tiller. Taylor's Power Law parameters were used to preparing sampling models according to Green (1970). Spatial distribution was determined as cumulative. Sample size decreased with increasing aphid population density in sampling models. In research precision level of (0.1), the sample size required at the highest average population density observed in the field (34.01/ tiller) was 136, which in precision level proposed for integrated pest management (0.25) reduced to 22 tillers. Overall, due to the large sample size at the precision level of 0.1, the model prepared at the precision level of integrated pest management (0.25) was recommended for monitoring S. avenae. The recommended model can reduce sample size more than six times at different densities in comparison to the sequential sampling model at the precision level of 0.1.

This study was conducted to develop a binomial (presence-non presence) sequential sampling model for saving time in determining population density of greenbug, Schizaphisgraminum (Rondani) in broom corn fields. For this purpose, 50 broom corn stems were sampled every three days for counting the aphid number. The mean and variance of population at each sampling date were used to estimate spatial dispersion parameters. Then, Taylor’s Power Law parameters were used to prepare binomial sequential sampling models at two precision levels of 0.10 and 0.25. The spatial distribution of S. graminum in the field was clumped and its mean population at different sampling dates ranged from 0.14 to 25.45 aphids per stem. Comparison of models showed that sample size required for estimating aphid population increased significantly by reducing the precision level from 0.25 to 010. Therefore, the binomial sequential sampling model at the precision level of 0.10 was very time consuming and was not suitable for estimating aphid population density. However, the model at 0.25 precision level reduced the required sample size compared to the fixed sample size method. Overall, using binomial sequential sampling model at 25% precision level, the proposed precision level for pest management programs can reduce sampling time in comparison to the fixed sample size method and is recommended for estimating the pest population in integrated pest management programs in broomcorn farms

The olfactory responses and biological attributes of Trichogramma evanescens (Te) and T. brassicae (Tb) were studied at laboratory conditions. Odor treatments included Carob moth eggs and healthy and infested pomegranate crown and seed and healthy and artificially damaged leaves. The olfactory apparatus consisted of a Y shape glass tube with 30° angle. Ninety mated females (0–24 hrs. old) of each species were exposed to the selected odor and clean air in 3 replications (each 30 wasps as one replication). In addition, biological characteristics of wasps were determined on Carob moth eggs using two sex age–staged life table approach. Olfactory results revealed that Te wasps significantly responded to the odors of Carob moth eggs and healthy and infested pomegranate crown and seed over clean air. In contrary, Tb wasps did not respond positively toward any tested odor. Considering biological trait investigations, Te male and female immature stage took 10.70 and 10.52 days being significantly shorter compared with that of Tb male (11.20 days) and female (10.95 days), respectively. Adult female Te had 3 days longevity which was one day longer than that of Tb wasps (2 days). The net reproductive rate and intrinsic rate of population increase of Te and Tb wasps were 16.56 offspring and 0.2337 day–1 and 15.20 offspring and 0.2220 day–1, respectively. Eventually, the transformation rate of host to parasitoid egg (Qp) was equal to 1 for both species. In order to select superior natural enemy candidates for biological control programs, the possibility of using fast olfactory tests instead of time consuming biological studies is discussed.

In this research, barley aphids in Mahidasht region of Kermanshah province were identified. Spatial distribution type and statistics for corn leaf aphid, Rhopalosiphum maidis (Fitch) were also studied and sequential sampling models were developed. Regular weekly sampling was carried out in 2015, 2016 and 2017. Each sampling date, 100 tillers were randomly visited and aphids were transferred to the laboratory for counting and identification. Taylor’s power law was used to determine spatial distribution type and statistics and sequential sampling models were developed according to Green (1970). Results revealed feeding of five species of aphids on barley including greenbug, Schizaphia graminum, rose-grain aphid, Metopolophium dirhodum, the English grain aphid, Sitobion avenae,corn leaf aphid, R. maidis and bird cherry-oat aphid, R. padi. Corn leaf aphid was more abundant during the season with 93.8%, 94.2% and 93.2% of aphids collected in 2015, 2016 and 2017, respectively. Low populations density of the other four species was observed every three years. Spatial distribution type of corn leaf aphid in barley field was determined as cumulative (b = 1.45). Sample size required in models with precision levels of 0.1 and 0.25 at mean aphid densities observed in the barley field (1.02 - 44.32 aphids per tiller) was 70 -524 and 11-84 tillers, respectively. In conclusion, sequential sampling model developed at the precision level of 0.1 was evaluated time consuming due to large sample size required, but the model at pest management precision level (0.25) was recommended for monitoring leaf corn aphid in barley fields.

Environmental factors including temperature and anticipation have critical impact on vegetative and reproductive growth as well as secondary metabolites and quantity and quality of essential oils in medicinal plants. In this study, phytochemical characteristics of German chamomilelandraces collected fromthree watershed areas of Kaleibarchai, Hajilarchai, and Mardanagim of Arasbaran, Iran was surveyed using plotting method. Foliar essential oils were extracted by hydro-distillation using Clevenger apparatus and their yield and compositions were determined using gas chromatography and gas chromatography mass spectrometer methods. On the whole, 22 components were identified in German chamomile essential oils with α-bisabolol, Camazulene, α-phellandrene, E- β-Franesol, Z-E- Feranesol, and α-bisabolol oxide as the most important identified components. High temperature and anticipation caused increasing of α-phellandrene, α-bisabolol oxide Z-E- Feranesol in Kaleibarchai region. Also, low anticipation in Hajilarchai increased Camazulene and E- β-Franesol. On the other hand, low temperature in Mardanagim increased Camazulene and α-bisabolol oxide in collected samples. Therefore, collection of German chamomile from Mardanagim for high amounts active medicinal ingredients is recommended.

The present research was carried out for determining spatial distribution type and developing sequential sampling models for precise estimating of corn leaf aphid, Rhopalosiphum maidis (Fitch) population in broomcorn, sorghum vulgare var. technicum, fields of Miyaneh region, Iran. To investigate spatial distribution pattern, population was sampled every 3 days on 50 broomcorn tillers to calculate variance and mean number of aphids at each sampling date. Taylor’s power law was more suitable and so its parameters was used to develop sequential sampling models using Green (1970) method at precision levels of D = 0.1 and D = 0.25. Results revealed high number of corn leaf aphid in broomcorn field with an aggregated dispersion pattern. Mean aphid population at different sampling dates varied from 5.22 to 109.10 aphids per stem. Estimates of spatial distribution parameters were used to develop sequential sampling models and sampling stop lines using Green (1970) method at precision levels of D = 0.1 and D = 0.25. Comparison of sampling models showed that sample size required for estimating aphid density significantly increased by decreasing precision level from 0.25 to 0.1. So, sequential sampling model at 0.10 precision level was time - consuming and it was not suitable for estimating corn leaf aphid population. However, sequential sampling model at 0.25 precision level reduced sample size required for monitoring R. maidis population in comparison to the fixed sample size method. In conclusion, sequential sampling model at 0.25 precision level could reduce sampling time and so, it recommended for estimating population in IPM programs of the pest in broomcorn fields of Miyaneh region.