JOURNAL OF ENTOMOLOGICAL RESEARCH
Year:2013 | Volume:5 | Issue:3 (19)|Papers Count:10

Spodoptera littoralis (Lepidoptera: Noctuidae) known as the African Cotton Leaf worm or Egyptian Cotton Leaf worm is one of the most common pests of cotton in the region of Adena, Turkey. The aim of this study was to determine the effects of a synthetic pyrethroid) Gammacyhalothrin) and neonicotinoids) Imidacloprid) on the pest to find out the resistance inducing process during several generations. Induced resistance to gamma-cyhalothrin up to 12 generations and to Imidacloprid for 7 generations was studied by assessing the resistance ratio (RR) of LC50 and LC90 with confidence limit of %95. The resistance ratios (RR) for LC50 and LC90 of gammacyhalothrin were calculated 16.85 and 18.82 and for Imidacloprid were 9.76 and 8.68, respectively.In order to study the effect of synergists on the insecticides, three different synergists including S, S, S-tributilfosforotritioat (DEF, (piperonyl butoxide (PBO) and diethyl maleate (DEM) were used and compared the Synergism Ratio (SR) with control. The highest SR for both insecticides belonged to application of DEM synergist. It is concluded that DEM could be recommended to be applied with Gamma-cyhalothrin and Imidacloprid to prevent or postpone the resistance induction into S.littoralis.

So far, 89 species belonging to 3 families and 8 subfamilies of Psylloidea superfamily has been recorded from Iran. In this study, a comparative revision has been done on the recorded species from all around of Iran and East-Azarbaijan province collected during the years 2010-2011 from grassy plants as well as foliage of trees has been conducted. Out of 6 families existed in the superfamily, 2 families, 7 genera, and 17 species were collected from the province, in which, 14 species are the new records for East-Azarbaijan province. Results showed that the present species of the province are of 3 families, namely, Triozidae, Psyllidae and Homotomidae, and the members of Triozidae family composes high density in the province, comparatively, 68.9 percent of the recorded species of the country are belonging to the family Psyllidae but 69.83 percent of the province species are related to Triozidae. Also, in this study the genus Bactericera showed the highest number of species in the province, however, Cacopsylla and Trioza are the most abundant genera in Iran, res of pectively.

Pistachio white leaf borer, Ocneria terebinthina Stgr. (Lep.: Lymantriidae) is one of the minor pests of pistachio in Iran. Some morphological characters and biology of the pest were studied in two orchards in Anar and Kerman, Iran. Ten pistachio trees (15-20 years old) and 60 leaves of each tree were selected from four different directions and visited twice a week. The eggs and larval emergence was recorded and cocoon formation was located. Seasonal occurrence of adults was recorded using light traps.. Our results revealed that pistachio white leaf borer, passes the winter as larval instar under loose bark on the trunk of pistachio trees or in white cocoons beneath plant litters. Activity of the overwintering larvae usually starts from the late March. Prepupal formed on the host leaves or bark crevices on infested trees. The adults appear in pistachio orchards in early spring (males appear earlier than females). Females lay eggs in batches on both the upper and lower surfaces of the pistachio leaves. The number of eggs in a single batch could be 4.75 to 361.This pest have 3 generations in Anar-Iran. In early autumn, the third instar larvae move toward diapausing shelters, molt to the fourth instar, make a whitish silk cocoon, and enter diapause.Overwintering larvae terminate diapauses at the end of winter and start feeding. Life cycle of the pest was also studied at two different temperatures i.e.25±2 and 30±2°C, %65±5 humidity and 14L: 10D h photoperiod. Results indicated that there was a significant difference between life cycle of the pest in these two temperatures (p<0.01). The longest period of development belonged to seven larval instar and the shortest to prepupal stage in both temperatures.

The cottony cushion scale Icerya purchasi Maskell is a polyphagous pest which has been distributed all around the word including Iran. The pest attacks to citrus and many other plants. The biology of I. purchasi at laboratory conditions (21.7oC, 75 R. H. and 10: 14 L: D) and its seasonal population fluctuations in two citrus orchards located in Sari (North of Iran) were studied during 2003- 2005. Samples were taken weekly from 10 trees in each orchard. Three 10cm twigs were taken randomly from each tree in each sampling occasion and number of adults and nymphs were recorded in laboratory. The mean number of eggs per female was 295.7 with incubation period of 9.1 days. Developmental period of the 1st, 2nd and 3rd instars was 19.5, 26.5 and 56.2 days respectively. Adults were observed from April to March. Three peaks of nymphs occurred in July, November and February and three for adults in May, August and February. According to these data, it is estimated that I. purchasi overwinters in all stages specially the 2nd instar nymphs. The investigation showed that the cottony cushion scale distributed throughout the east of Mazandaran from Behshahr to Noor.

The intracellular symbiont bacterium, Wolbachia is known as a reproductive parasite in different species of Trichogramma. Regard to importance of this symbiont in biological control programms, the present study addressed the efficiency of wsp gene to typing this symbiont from some populations of Trichogramma and also its prevalence. In this study which conducted through 2009 to 2010, 19 populations of Trichogramma were screened for Wolbachia infection.Among these, seven populations were determined as infected by Wolbachia. Eight strains of the bacterium were characterized which six strains belonged to subgroup Kue from A supergroup.The two remained strains were related to B supergroup and Sib subgroup. The double infection and superinfection were observed in Trichogramma populations. Among three species, T. embryophagum, T. brassicae and T. evanescens, the highest prevalence of Wolbachia was observed in T. brassicae with 57 % of samples populations. The most infection rate belonged to populations of Mazandaran province. Despite the separation of different strains of Wolbachia on the basis of wsp gene, recombination analysis indicated a doubt about the grouping results of this symbiont inferring from this gene. This analysis indicated existence of some genetic exchangesbetween different strains of Wolbachia in wsp gene. The new approach called Multilocus Sequence Typing (MLST system) could be effective solution in more accurate characterization of these endosymbionts.

ISSR molecular marker, in order to isolate the Iranian native Bombyx mori silkworm breeds were used. Extracted DNA by using phenol-chloroform was performed. The qualitative and quantitative measurements of extracted DNA and its dilution, was obtained from the bands on 1.5% agarose gel and they marked and analyzed. The results showed that the observed bands were between 200-1000 bp and the most bands were observed corresponding to Harati-yellow with 32 bands and Khorasani-lemon had their lowest with 25 bands. Second Primers were the highest number of bands with 43 bands and the fourth primer had the lowest number of bands with 30 bands. Cluster analysis of races, placed them in three main groups. The first groups consisted of Gilani-orange, Harati-yellow and Khorasani-pink, Khorasani-lemon and Baghdadi races placed in seprate groups. In cluster analysis, Gilani-orange showed the most similar to Herati-yellow and this two races with khorasani-pink were the first group. The most genetic similarity were between Gilani-orange and Herati–yellow and the most genetic distance was obtained between Baghdadi and other four races. It is concluded that, ISSR marker can seperate different races of silkworm with different origin very well.there fore to approve the it is suitalle to use more than more than 30 primer for 14 silkworm individuals with 2n=28 is better.

Onion thrips is a key pest of vegetable crops. Chemical control is a conventional control method of onion thrips. The infested fields to onion thrips are usually treated several times each year. This study was conducted in the laboratory conditions to find the effective insecticides by using the filter paper bioassay. Cypermethrin EC10%, deltamethrin EC2.5%, diazinon EC60%, oxymatrine AS 0.6%, and spinosad (TracerÒ SC240) were used in the bioassay. The filter papers were dipped in sequential concentrations of the insecticides The median lethal concentration (LC50) of insecticides was determined on 4 day-old adult thrips at 24 hours after treatments. The LC50 values of the insecticides were included 38.08, 3.08, 47.4, 2.43 and 4.8 a.i. mg/ml respectively.Oxymatrine and diazinon had the highest and lowest toxicity on T. tabaci respectively. Thus, oxymatrine can be considered as a new effective insecticide against onion thrips with low risk on environment and human.

In this study, the efficacy of three types of protein hydrolysate (Esmelfol, Bio-cebo and Agrisence) and three different graed area baiting (50, 75 and 100 percent plot coverage of baiting) were compared with control (without spraying) and malathion spraying treatments in Jahrom region (Fars province) (Iran) in 2011. Parameters like infested fruits percent, precent efficacy, and yield (Kg) in experimental plots were componed. The maximum and minimum percentage of infested fruits were observed in control (28.5%) and 100% plot coverage of baithng with Agrisence formulation, respectively. The maximum and minimum of perecent efficacy were observed in 100% plot coverage of baiting with Agrisence formulation (95.13%) and malathion spraying (61.03%) respectively. The maximum and minimum yield in 100% plot coverage of spraying with Agrisence formulation (1600 kg/plot) and control (466.7 kg/plot) respectively. Significance differences were not observed among the various levels of plot coverage of bait spraying with all protein hydrolysate formulations. It has been concluded that Baiting obtained of 50 percent of the cultivated melon fields in spring with any type of mentioned protein hydrolysate formulations (especially Agriscens company product) will be very effective and economic to control melon fly in Jahrom region.

In this study, the adult wasps were exposed to fresh residuces of the insecticide. The LC50 value of pyridalil were 2451 ppm. Sublethal effects of pyridalil on life table, reproduction parameters and survivorship of H. hebetor were studied. The survivorship was affected by the insecticide. Life expectancy and Mortality rate were not significantly affected but reproduction parameters of H.hebetor was affected by the insecticide. Mortality of egg and larval stages was significantly affected by the insecticide, but the adult emergence rate was not significantly affected by the pyridalil. Results showed that pyridalil insecticide had less adverse effects on the parasitoid. Field studies aiming to assess efficacy of combined use of insecticide and H. hebetor is needed to obtain more applicable results.

During 2006, in the course of faunistical survey of water mites of Guilan Province, Eylais degenerata Koenike, 1897, Aturus intermedius Protz, 1900 and Arrenurus walkanoffi K.Viets, 1926 (Acari, Hydrachnidia) as three new species of aquatic mites for Iran fauna were collected and identified.