Population fluctuation

Open Access Article

1 - Seasonal population fluctuations of the cabbage white butterfly, Pierisrapaein cauliflower fields of the South of Tehran
Gholamhosein Hasanshahi Zahra Dousti Fatemeh Jahan Alireza Askarianzadeh Jaber Karimi Habib Abbasipur

The cabbage white butterfly, Pierisrapae (Linnaeus, 1758) (Lep.: Pieridae) is one of the most important pests of Cruciferous or Brassicaceaefamily plants in regions of Shahriar, Kahrizak and Sahr’e Ray and every year its damage can be seen on the leaves of these p More

The cabbage white butterfly, Pierisrapae (Linnaeus, 1758) (Lep.: Pieridae) is one of the most important pests of Cruciferous or Brassicaceaefamily plants in regions of Shahriar, Kahrizak and Sahr’e Ray and every year its damage can be seen on the leaves of these plants. In order to study the seasonal population fluctuation of P. rapae, One hectare cauliflower field in the middle of a large field was randomly selected in five regions of cauliflower fields in southof Tehran were chosen and sampled every 10 days. Each plant was presumed as a sampling unit and sample size was determined as 20 host plants and all eggs, larvae and pupa on the host plant were recorded. Results of this study showed that Jahanabad and Shahed fields had the highest egg density (18.91±5.60) and the lowest egg density (16.53±4.04) was seen in the Playin field during season. In the Shahed field, highest egg density occurred in June 19 and the lowest egg density was seen on October 25. In the Playin field, the highest and lowest egg density was seen on September 29 and June 19, respectively. In the Jahanabad field the highest (2.99±0.66) and lowest (0.41±0.10) larval density was occurred during the season among different regions. Highest density was observed in the Jahanabad field during the harvest time on October 25 and the lowest larval density was seen on June 19. The highest and lowest larval density was seen in the field of Playin  on 25rd October and 19th June, respectively. Kahrizak (0.87±0.16) and Playin (0.19±0.05) fields had the highest and lowest pupal density in different regions during the season. In the field of Kahrizak, highest pupal density was occurred on 25rd October and in the playin field, the lowest pupal density was seen on 19th June. In the Playin field, highest density of pupae was occurred on 14th October and 25rd October and the lowest density of pupae was observed on 19th June and 2th July, respectively. The results showed that number of larval and pupal stages based on units density, between all experimental regions and Shahed university station had not significant difference. Manuscript profile

Open Access Article

2 - Species Diversity and Population Fluctuation of Heteroptera Predators in Rice Fields of Mazandaran Province, Northern Iran
Hassan Ghahari Hadi Ostovan Mehrdad Tabari

The predator bugs (Heteroptera) are one of the powerful natural enemies in almost agro-ecosystems which have important role in biological control programs. In attention to presence of diverse pests in rice fields and importance of this crop as the main food in Northern More

The predator bugs (Heteroptera) are one of the powerful natural enemies in almost agro-ecosystems which have important role in biological control programs. In attention to presence of diverse pests in rice fields and importance of this crop as the main food in Northern Iran, species diversity and population fluctuation of predator bugs were studied in rice fields of Mazandaran province through 2005 - 2006. In a total, 20 species of predator bugs were collected and identified from rice fields of Mazandaran province. Of the collected species, eight species including, Oncocephalus pilicornis Reuter, Oncocephalus plumicornis (Germar), Reduvius pallipes Klug, Rhynocoris iracundus (Poda) and Coranus cf. niger Rambur of family Reduviidae, Stenodema calcaratum (Fieb.), Orthotylus flavosparsus (C.Sahlb.) of family Miridae, and Brachynema puncticornis Rt. of family Pentatomidae are newly recorded from Iran. The results of population fluctuation indicated that the density of predator bugs increases through the crop season gradually, but application of insecticides causes damage to the density population severely. Also, the population density of predator bugs was varied through a day; the most abundant of population was obtained in hours 10 and 18, because of moderate climate. These beneficial insects rest beyond the rice seedlings and among the weeds around the fields through the hours 12 - 16, because of high temperature and humidity in rice fields. The results of population density of predator bugs on three rice varieties including, Fajr, Khazar, and Nemat indicated that highest density was obtained from Fajr and there was not significant difference between the two other varieties. Since the Fajr is a sensitive variety to C. suppressalis and the pest population density on it is higher than other studied varieties, there is higher density of heteropteran predators on this variety than the two others. Manuscript profile

Open Access Article

3 - The effects of climatic conditions on seasonal population fluctuation of date palm scale Parlatoria blanchardi Targ. (Hem.: Dispididae)
Masoud Latifian Mahshid Zaerae

Palatoria blanchardi Targ. is an important of date palm in Iran. The population was monitored monthly by leaf sampling during 4 years (2000-2004). Sample unit was 3 leaves that taken from 3 strata of the palm canopy of ten trees. Weather data (temperature and relative h More

Palatoria blanchardi Targ. is an important of date palm in Iran. The population was monitored monthly by leaf sampling during 4 years (2000-2004). Sample unit was 3 leaves that taken from 3 strata of the palm canopy of ten trees. Weather data (temperature and relative humidity) were obtained from Abadan meteorology station. Correlation analysis and sigmoid models including Monomolecular, Logistic, Gompertz, Weibull and Richard models were used to study the relationship between population density and  weather parameters. Pest activities started in March and population increased by increasing of temperature and humidity. Result showed that there were three overlapping periods of activities in field. The first, second and third periods of activities started in April, September and December respectively. The first period was longest and the third period was shortest. There was significant correlation between population abundance and weather condition including temperature and relative humidity. The order of relative influences of climatic factors on seasonal population fluctuation showed that the effect of temperature was greater than the effect of relative humidity. The highest population occurred when temperature was between 16 º C and 24 º C and relative humidity was between 42 and 63 percent.  Manuscript profile

Open Access Article

4 - Effect of two cotton cultivars on population fluctuations of spider mites (Acari : Tetranychidae)
Seyed Hamid Reza Forghani Hadi Ostovan Javad Shaterian Nazila Honarparvar

Cotton plant, Gossypium hirsutum L., is one of the most economic crop around the world and in GonbadKavous (located in North of Iran) is an important cotton cropping region. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damaging pests on the fie More

Cotton plant, Gossypium hirsutum L., is one of the most economic crop around the world and in GonbadKavous (located in North of Iran) is an important cotton cropping region. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damaging pests on the field crops. Use of resistant cultivar is one of the foremost accepted chemical-free techniques for controlling this pest. A two year study was conducted to evaluate resistance of two most-cultivated cultivars, sahel and siokra, against spider mites. The results showed that there was a significant difference in population of spider mites, so that the population on Sahel was more than Siokra for two years studied. The separate population figures for each year recorded 10.3 ± 0.6 eggs and 24.2 ± 1.3 mites on Sahel, 7.4 ± 0.4 eggs and 15.9 ± 0.9 mites on Siokra in first year whereas it was 22.6 ± 2.1 eggs and 35.2 ± 2.6 mites and also 8.6 ± 0.5 eggs and 16.9 ± 1.1 mites in second year for them. Mite’s populations increased from mid-season to the end of growing period. The results showed that effects of ambient temperatures on egg populations and number of active stages of mites was more favorable on Sahel compared with Siokra. Population assessment of mites on these two cultivars can be used in management of the pest.  Manuscript profile

Open Access Article

5 - Biology of potato tuber moth, Phthorimea operculella Zeller (Lep.: Gelechidae), on two potato cultivars
M. Shahabi A. Rajabpour

Potato tuber moth, Phthorimea operculella, is one of the most important pests of potato in Iran. Biology of the pest on two commercial potato cultivars, Sante and Arinda, was studied in Andimeshk, north of Khuzestan province, Iran. Samplings were weekly performed from t More

Potato tuber moth, Phthorimea operculella, is one of the most important pests of potato in Iran. Biology of the pest on two commercial potato cultivars, Sante and Arinda, was studied in Andimeshk, north of Khuzestan province, Iran. Samplings were weekly performed from two separate fields cultivated by two cultivars during two agricultural seasons (2013-2015).  Adults and immatures monitoring were done by using sex pheromone trap and direct count respectively. Results showed that adults occurred with two months difference in the first and second agricultural seasons which is related to different means temperature in the two studied seasons. Significant correlation was observed between adult densities and weekly means temperature. First adults appeared on both cultivars in early February and December in the first and second agricultural seasons and peaked at the end of March, respectively. The peaks of egg number were observed at The end of March for the first and second agricultural seasons, respectively. First larvae were observed in early and mid of March in the first and second years.  Larvae peaked at The end of March and mid of April for the first and second years, respectively. No considerable difference was observed among occurrence, peak and activity time of the developmental stages of potato tuberworm on The two tested cultivars. Manuscript profile

Open Access Article

6 - The seasonal population fluctuations of pomegranate fruit moth, Ectomyelois ceratoniae Zeller and quince moth, Euzophera bigella Zeller in pomegranate orchards
N. Naserian H. Farazmand R. Vafaei Shoushtari A. Avand-Faghih N. Azadbakht

The pomegranate fruit moth, Ectomyelois ceratoniae Zeller, and quince moth, Euzophera bigella Zeller, are the major frugivorous pest. They cause qualitative and quantitative losses of pomegranate fruit. Sexual pheromone traps may provide a real estimation of adult emerg More

The pomegranate fruit moth, Ectomyelois ceratoniae Zeller, and quince moth, Euzophera bigella Zeller, are the major frugivorous pest. They cause qualitative and quantitative losses of pomegranate fruit. Sexual pheromone traps may provide a real estimation of adult emergence and flight activity periods, emigration and immigration of such pests. To fulfill such a purpose, an experiment was performed to observe the population fluctuation of E. ceratoniae and E. bigella using synthetic pheromone traps in pomegranate orchards of Tang-e-Siab Koohdasht (Lorestan, Iran), in 2011. Adults of E. ceratoniae and E. bigella appeared in late April and May, respectively, and their flights continued until mid November. These pests populations showed four and three flight peaks during the growth season, respectively. The quince moth's population was higher than on pomegranate fruit moth's population, while the peak of the moth flight was between late July to early August. So in the pomegranate orchards of Lorestan region, in addition to pomegranate fruit moth, quince moth is one of the important fruit pests. The quince moth appears a month later in comparison to pomegranate fruit moth and both are active until the end of the season. Manuscript profile

Open Access Article

7 - The population fluctuations of Euzophera bigella (Zeller) and Cydia pomonella (L.) at quince orchards
P. Kermani H. Farazmand J. Karimzadeh A. Avand-Faghih

The lepidopterans Euzophera bigella (Zeller) (Pyralidae) and Cydia pomonella (L.) (Tortricidae) are the most important pests of quince trees in Iran, as they cause the qualitative and quantitative losses on quince fruits. The present study was performed to monitor the p More

The lepidopterans Euzophera bigella (Zeller) (Pyralidae) and Cydia pomonella (L.) (Tortricidae) are the most important pests of quince trees in Iran, as they cause the qualitative and quantitative losses on quince fruits. The present study was performed to monitor the population fluctuations of E. bigella and L. pomonella using synthetic pheromone traps at quince orchards in Falavarjan (Isfahan, Iran). In addition, the influence of climatic factors on population fluctuations was studied. It was found that E. bigella adults appeared in early March, showing four population peaks during growth season. The adults of L. pomonella were, however, showed up in middle March with five seasonal population peaks. The populations of male E. bigella were positively correlated with relative humidity, weekly rainfall (up to 3.5 mm), weekly means of minimum and maximum relative humidity and temperature (higher than 25 °C). In addition, when rainfall was 1.2 mm, no significant effects of weekly means of minimum and maximum relative humidity and temperature were observed on E. bigella densities. The population densities of male E. bigella also showed a significant positive correlation (r = 0.58) with relative humidity. Manuscript profile

Open Access Article

8 - Investigation on Spodoptera spp. (Lep., Noctuidae) and its population fluctuation using phero-traps in beetroot farms of Isfahan region
E. Danyalzadeh A. Avand-Faghih H. Farazmand J. Karimzadeh

S.exigua, S. litura and S. littoralis with a wide host range are the most important pests of beet. spread all over the word while two other species S. littoralis and S. litura are more limited. Spread seasonal fluctuations of these species population along the growing s More

S.exigua, S. litura and S. littoralis with a wide host range are the most important pests of beet. spread all over the word while two other species S. littoralis and S. litura are more limited. Spread seasonal fluctuations of these species population along the growing season were studied by green funnel traps that were bated by sexual pheromone in a beet farm near Esfahan in 2010. S. exigua and S. littoralis were captured in traps but S. litura was not captured in pheromone traps because S. exigua and S. littoralis are similar concerning their molecules and their proportion. From mid-October as the weather gets cold, it reduced to the least. The average of trapped of S. littoralis was low till August and almost was fixed and any max or min was not observed. But trapped pests increased from 9Th September and it became maximum in mid-October. Results showed that the time of activation of these species were different in that the population of S. exigua was more than S. littoralis in the beginning of growing season of beet till late summer. But in the end of growing season means the population of S. littoralis was increase in late summer till autumn and over numbered to S. exigua population. Manuscript profile

Open Access Article

9 - Seasonal population fluctuations of Mediterranean pine bark beetle, Orthotomicus erosus (Wollaston) (Coleoptera:Curculionidae:Scolytinae), in the Tehran Chitgar forest park
T. Arkani H. Ostovan H. Farazmand M. Gheybi

One of the main problems of pine trees in the Chitgar park located in Tehran, Iran, is pine bark beetles, which not only cause direct harms to these trees but also is vector of some viral  and bacterial pathogens. To study the seasonal population fluctuations of th More

One of the main problems of pine trees in the Chitgar park located in Tehran, Iran, is pine bark beetles, which not only cause direct harms to these trees but also is vector of some viral  and bacterial pathogens. To study the seasonal population fluctuations of the pest, the sampling process of adults from pine barks was performed in different regions of the park in 2015 to 2017. Twelve infected centers in the park were selected and four cross trap were installed in each center. The mass capturing pheromone of Orthotomicus erosus and pine kairomone dispensers were used in each trap. The distance between traps was about 50 meters. According to the observed data, the emergence of adult beetles was started in early April and continued until mid-December. The average daily capture per trap was four beetles. From mid-December onwards, no beetles were caught in the traps. Mediteranean pine bark beetle had at least six flight peaks in the area of study. The most trapping were observed in 8 June, 28 June, 27 July, 16 August, 5 September and 25 September respectively. The The highest number of trap catches was registered in September, July, August, June, September and October, with 9.2, 7.7, 7.2, 5.7, 2.4 and 1.6 beetles per trap respectively. Also, the mean average of total capture during spring, summer, autumn and winter were 401, 1159,114 and zero beetles per trap; so, the most activity of the pest was observed in summer, spring and autumn respectively The highest number of beetle was in the north and the least was captured in the south of the park. Manuscript profile

Open Access Article

10 - Population fluctuation of egg parasitoids of sunn pest and determining of dominant species in Varamin and vicinity
Hasan Ghahari

Population fluctuation of sunn pests’ parasitoids (Scelionidae and Encyrtidae) was studied in 5 different localities of Varamin including, Javad-Abad, Dehmacin, Gharchak, Asgar-Abad and Pishva. Seven parasitoid species including, Telenomuschloropus, Trissolcusbasa More

Population fluctuation of sunn pests’ parasitoids (Scelionidae and Encyrtidae) was studied in 5 different localities of Varamin including, Javad-Abad, Dehmacin, Gharchak, Asgar-Abad and Pishva. Seven parasitoid species including, Telenomuschloropus, Trissolcusbasalis, Tr. grandis, Tr. rufiventris, Tr. semistriatus, Tr. vassilievi and Ooencyrtustelenomicida were collected from the mentioned regions. Upon the samplings in Gharchak, 4 species, T. semistriatus, T. grandis, T. Vassilievi and T. Rufiventris, were collected which of these T. semistriatus and T. grandis were determined as dominant species. Mean percent parasitism of T. semistriatus was higher than the other species and the highest parasitism (44.63%) was obtained in 22 May 2014. In Pishva, 5 parasitoids, T. grandis, T. vassilievi, T. semistriatus, T. chloropus and T. Basalis, were collected, which T. grandisand T. vassilievi were the dominant. The parasitism of these two parasitoids were started in 10 April 2014 and the maximum parasitism of T. grandis(27.89%) in 22 May 2014 and for T. vassilievi (22.39%) in 29 May 2014. Parasitoids of sunn pest in Javad-Abad were identified as T. rufiventris, T. grandis and Telenomus chloropus which of these, T. rufiventris was determined as the dominant species. The beginning of its parasitism activity was observed in 17 April 2014 and its maximum (26.44%) in 7 May 2014. The collected species in Dehmacin were included T. semistriatus, T. vassilievi, T. grandis and O. telenomicida which 2 species T. semistriatus and O. telenomicida were the dominant. The maximum percent parasitism was obtained in 22 May 2014 for T. semistriatus and 29 May 2014 for O. telenomicida. Six parasitoid species including, O. telenomicida, T. rufiventris, T. vassilievi, T. grandis, T. semistriatus and T. simony were collected from Asgar-Abad, which of these 3 first species were the dominant species. The highest percent parasitism for T. vassilievi(16.68%) and T. rufiventris (13.21%) was obtained in 22 May, 2014, and for T. grandis(23.72%)in 5 June 2014. Regarding to sex ratio of parasitoids, mean percent of emerged females was more than the male production in all sampled regions. Manuscript profile

Open Access Article

11 - Population fluctuation of broom corn aphid parasitoids in Miyaneh region, Iran
Shahram Shahrokhi Habibollah Khodabandeh Koroush Siami

Aphids are the most injurious pests of broom corn in Miyaneh region, Iran. Chemicals are used in different times for plant protection by farmers, regardless to natural enemy activity. Identification of native natural enemies is essential in integrated pest management pr More

Aphids are the most injurious pests of broom corn in Miyaneh region, Iran. Chemicals are used in different times for plant protection by farmers, regardless to natural enemy activity. Identification of native natural enemies is essential in integrated pest management programs. In this research, broom corn aphid parasitoids were collected and identified and their population fluctuations were also studied in comparison to their aphid hosts. For this purpose, aphid colonies were sampled and mummies were collected. Live aphids were also reared on broom corn seedlings for 10 days to select parasitized aphids from unparasitized ones. Results revealed that, there were two aphid species in broom corn fields of Miyaneh region, including Schizaphis graminum and Rhopalosiphum maidis. Parasitoids were collected on both mentioned aphids and were belong to genus Aphelinus, family Aphelinidae. High parasitoid population was seen when aphid population was high, and vise versa. Significant positive correlation of aphid and parasitoid populations was duo to host specificity and might be a criterion of effective natural enemies. Manuscript profile

Open Access Article

12 - Biology and population fluctuation of broom corn aphids in Miyaneh region, Iran
Shahram Shahrokhi Habib Ollah Khodabandeh Koroush Siami

Broom corn is one of the most important crops in Miyaneh region, Iran. Aphids are major pests of the crop and farmers use different chemicals to their control in several times. In this research, broom corn aphids were collected and identified. Population fluctuation of More

Broom corn is one of the most important crops in Miyaneh region, Iran. Aphids are major pests of the crop and farmers use different chemicals to their control in several times. In this research, broom corn aphids were collected and identified. Population fluctuation of the aphids was also investigated by weekly sampling and their biological characteristics were studied using leaf cages. The results revealed that, there were two species including Schizaphis graminum and Rhopalosiphum maidis in broom corn fields. Population peak of S. graminum (mean number of 10.725 aphids per tiller) was observed in June and decreased rapidly in July. R. maidis appeared later than S. graminum, but it was the most injurious aphid species of  broom corn during all growing season. R. maidis population and it’s honeydew covered some plants and caused necrosis so that it’s number reached more than 1000 aphids per tiller. Mean number of this species reached to 114.75 aphids per tiller and then decreased rapidly. In laboratory studies, mortality rate of S. graminum and  R. maidis on broom corn leaves was relatively low (3.2 and 5.6 percent). Nymphs of both species matured in less than 10 days. Mean longevity and mean fertility of mentioned aphid species was 28.2 and 32.6 days and 41.84 and 49.7 nymphs per female respectively. Mean generation time of S. graminum and R. maidis was also 11.3 and 10.9 days respectively. Manuscript profile

Open Access Article

13 - Population fluctuations of broom corn aphid specific predators in Miyaneh region, Iran
Shahram Shahrokhi Habib Ollah Khodabandeh Koroush Siami Jaber Davoodi

Aphids are the most important pests of broom corn, Sorghum cernuum, in Miyaneh region and chemical pesticides are severally used for plant protection by farmers regardless to beneficial insect’s activity. With respect to the importance of conservation strategy of More

Aphids are the most important pests of broom corn, Sorghum cernuum, in Miyaneh region and chemical pesticides are severally used for plant protection by farmers regardless to beneficial insect’s activity. With respect to the importance of conservation strategy of natural enemies in integrated pest management programs, aphid specific predators including lady beetles, flower flies and lacewings were collected and identified and their population fluctuation were compared to that of host aphids. Collection of predators was done by sweep net and visiting aphid colonies. The flower fly Sphaerophoria scripta , lacewing Chrysoperla carnea, and five species of lady beetles including: Coccinella septempunctata, C. undecimpunctata، ،Hippodamia variegata، Scymnus cf. frontalis and Propylea quatuordecimpunctat were  collected from greenbug, Schizaphis graminum and maize leaf aphid, Rhopalosiphum maidis colonies. Synchronization and positive correlation of greenbug and flower fly populations was observed due to host specificity of Sphaerophoria scripta . Among lady beetles, Scymnus cf. frontalis was the most frequent and important species due to oviposition on broom corn and it’s population showed positive significant correlation with that of maize leaf aphid. However adult lacewing Chrysoperla carnea is a carbohydrate feeder and did not lay any egg on the field, and so it had not any role in controling aphid populations of broom corn. Manuscript profile

Open Access Article

14 - Faunistic survey and population fluctuations of ants (Hymenoptera: Formicidae) as predators of pests of rice fields in Mazandaran, Iran
Hassan Ghahari mehrdad Tabari abolfazl Rashidi hamireza Mohebbi

Ants (Hymenoptera: Formicidae) are one of the important predators in different agroecosystems. Considering the importance of ants in predating and feeding at different life stages of pests, fauna and population fluctuation of these beneficial insects were studied in ric More

Ants (Hymenoptera: Formicidae) are one of the important predators in different agroecosystems. Considering the importance of ants in predating and feeding at different life stages of pests, fauna and population fluctuation of these beneficial insects were studied in rice fields of Mazandaran province. Of the faunistic survey, totally 15 species of ants were collected and identified from the paddy fields in Mazandaran province. The results of population fluctuations on the stubbles of three varieties including, Fajr, Khazar and Nemat indicated that the ants' population density was higher on Fajr than the two other varieties, and there was not a significant difference between Khazar and Nemat. Samplings from 11 September to 15 November 2005 indicated that the population density increased until last October and then decreased gradually; the highest density was obtained in 30 October. The means comparison revealed the significant reciprocal effect of "sampling date × rice variety" on population density of ants "P<0.01". Manuscript profile

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