Journal of Entomological Society of Iran
Year:2014 | Volume:34 | Issue:1|Papers Count:12

Beet armyworm, Spodoptera exigua (Hubner), is an important pest of field crops with a wide range of host plants. Using safer insecticides, such as insect growth regulators (IGRs), with different modes of action and lower possibility of development of resistance would be useful for an effective control program. The effects of three IGRs namely methoxyfenozide, lufenuron and flufenoxuron were assessed on 1st instar larvae of S. exigua. The bioassays were performed using diet incorporation and leaf dipping methods. Mortalities were recorded 144 hours after the treatment. The LC50 values for methoxyfenozide, flufenoxuron and lufenuron were found to be 0.154, 0.254 and 2.398 mg ai/l, in diet incorporation method; and 1.302, 0.427and 3.510 mg ai/l in leaf dipping method, respectively. Based on the 95% confidence interval of the ratios of LC50s, for all of the insecticides tested, the LC50 values were significantly different in the two bioassay methods used. Lufenuron had the lowest toxicity against the 1st instars of beet armyworm in both assays. All insecticides were effective against 1st instar larvae of beet armyworm at low concentrations.

The efficiency of methanolic extracts of Fumaria parviflora (Lam.) (Fumariaceae) and Teucrium polium (L.) (Lamiaceae) on the sweet potato whitefly, Bemisia tabaci (Genn.), and its side effects on the common green lacewing, Chrysoperla carnea (Stephens), comparing with pymetrozin were studied in laboratory conditions. The calculated LC50 values for pymetrozin and plant extracts were used for spraying the tomato plant pots, which had been caged and covered with fabric mesh, while cardboard chambers containing lacewing eggs hanged from tomato plants. The experiments were carried out at 25 ± 5 °C, 50 ± 5 RH and photoperiod of 16: 8 h (L: D). The LC50 for T. polium and F. parviflora extracts as well as pymetrozin were found out to be 82.629, 23.002 and 0.118 mg/ml, respectively. The rate of population reduction of B. tabaci by F. parviflora and T. polium extracts, pymetrozin and common green lacewing was 86.91, 83.51, 84.29 and 54.26 percent in egg stage; 81.39, 79.68, 78.05 and 52.40 percent in nymphal stage; 82.76, 77.31, 78.12 and 44.99 percent in total immature stages as well as 83.01, 81.07, 79.00 and 64.20 in total nymphal stages. Findings showed that the herbal extracts can be used as alternative chemicals in place of pesticides in natural conditions.

The Sunn pest, Eurygaster integriceps Puton, is a univoltine insect and considered as one of the most important pests of wheat and barley. The adults of E. integriceps migrate to higher altitude in mountains for about nine months to complete their aestivation and hibernation period. To measure the cry oprotectants compounds, the insects were collected monthly between August 2009 and May 2010 in an altitude of 2000 meters and from wheat fields on the outskirts of Kabudarahang in the province of Hamadan. The level of cry oprotectants was determined using high performance liquid chromatography (HPLC). The identified compounds were trehalose, glycerol, glucose, myo inositol, ribitol and sorbitol. It appears that trehalose and glycerol are the major cry oprotectants The amount of trehalose significantly increased from 1.36 mmol/g fresh weight (f. w.) in September to 8.26 mmol/g f. w. in December. The amount of glycerol (22.36 mmol/g f. w.) and glucose (8.97 mmol/g f. w.) were at their highest levels in February and December, respectively. The amount of total cry oprotectants significantly increased from 12.28 mmol/g f. w. in September to 44.07 mmol/g f. w. in February. Results show that the Sunn pest has a great capacity to synthesize various cry oprotectants.

The ladybird species Oenopia conglobata contaminata (Menetries) is one of the major predators of pests in the orchards across Iran. The life history and predation rate of this predator were studied under laboratory conditions with 27.5 ± 2oC, 55 ± 5 RH and 16: 8 h (L: D) photoperiod to 6-cm petri dishes. To study the demography, a cohort containing about 100 eggs with less than 24h of age was chosen. Ladybeetle larvae were fed daily on the immature stages of pomegranate green aphids, Aphis punicae Pass. The daily fertility, immature developmental time, mortality and predation rate data were analyzed using age-stage, two-sex life table analysis - MSChart software. Means and standard errors of population growth parameters were calculated by bootstrap method. To determine the predation rate, the first-instar beetle larvae were fed on the third and forth developmental stages of A. punicae. The adult ladybirds were grouped in pairs of opposite sexes to investigate their predation rates on daily basis. The intrinsic rate of increase (rm), finite rate of increase (l), mean generation time (T0) and net reproductive rate (R0) were 0.181 d-1, 1.198 d-1, 30.58 d and 251.65 offspring per individual respectively. Predation rate of different stages of forth-instar larvae and both adult sexes were 49.56, 95 and 125, aphids respectively, and the average predation rate (C0) was 118 aphids that shows a high rate of predation on the aphid population.

The parasitoid and hyper parasitoid chalcidoid wasps of scale insects deposited at the Hayk Mirzayans Insect Museum (affiliated to the Iranian Research Institute of Plant Protection, Tehran, Iran) were studied. The specimens had been collected from different parts of Iran and belonged to four families. The following 35 species were identified:Aphelinidae: Ablerus atomon (Walker), Ablerus sp., Aphytis chrysomphali (Mercet), A. mytilaspidis (Le Baron), A. proclia (Walker), Coocobius testaceus (Masi), Coccobius sp., Coccophagus insidiator (Dalman), C. lycimnia (Walker), C. piceae Erdos, C. pseudococci Compere, Encarsia aurantii (Howard), E. berlesei (Howard), E. citrina (Craw), E. fasciata (Malenotti), Marietta picta (André).Encyrtidae: Anagyrus agraensis Saraswat, A. dactylopii (Howard), A. mirzai Agarwal & Alam, A. pseudococci (Girault), Blastothrix ilicicola Mercet, B. sericea (Dalman), Cerapterocerus mirabilis Westwood, Comperiella bifasciata Howard, Encyrtus aurantii (Geoffroy), Metaphycus angustifrons Compere, M. pulvinariae (Howard), M. punctipes (Dalman), Microterys hortulanus Erdos, M. lunatus (Dalman), M. nietneri (Motschulsky), Mi. nuticaudatus Xu.Pteromalidae: Moranila californica (Howard), Pachyneuron muscarum (Linnaeus). Signiphoridae: Chartocerus sp. The two species of C. insidiator and C. piceae are found to be new records for the Iranian insect fauna.

The acaricidal activity of new formulation of Neem EC 1.28% was compared with Neem Azal® (EC 1%) and spirodiclofen against the two-spotted spider mite, Tetranychus urticae Koch, under both laboratory and field conditions. The method of leaf dipping was used for bioassay experiments. The common bean leaves were dipped into different concentrations of treatments before exposing them to the adult mites from the same age. The mortality for mites was recorded after 24 hours. The experiment was conducted under 25 ± 2ºC, RH 60 ± 5 %, and 16: 8 (L: D) h photoperiod conditions. LC50 and related parameters were calculated, using POLO-PC software. The field studies were conducted in randomized complete block design with five treatments of 1 ml/l, 2 ml/l and 3 ml/l of EC 1.28% formulation, 0.5 ml/l spirodiclofen and 1 ml/l of Neem Azal®. Plain water was used for the control group. The LC50 values for Neem Azal®, spirodiclofen and Neem EC 1.28% formulation were 52.04 mg/l, 37.55 mg/l and 21.06 mg/l, respectively. The results showed that mites were more susceptible to the new EC 1.28% formulation. In the field, spirodiclofen was found to be the most effective compound after 3 and 7 days of treatment causing 89.3 ± 1.7% and 77.8 ± 2.3% mortality, while Neem Azal® was less effective with 64.40 ± 4.04% and 68.7 ± 2.9% mortality on mites. The new EC 1.28% formulation was used at the rate of 3 ml/l, which caused 82.8 ± 2.4% and 70.2 ± 3.9% mortality, without significant difference with spirodiclofen treatment.

The psocid specimens were collected from Isfahan in 2009 and later identified as Liposcelis paeta Pearman and L. bostrychophila Badonnel (Psocoptera: Liposcelididae). The species L. paeta is recorded here for the first time from Iran. This finding increases the number of known Iranian members of the family Liposcelididae to five species

The species Dibrachys lignicola Graham is newly recorded from Rayen region of Kerman province, Iran. The diagnostic characters and geographical distribution of the species are briefly discussed

During a study on the pests of button mushrooms in the city of Kermanshah, the sphaerocerid species of Pullimosina heteroneura (Haliday) was collected from mushroom culture media. This species is a new record for the Iranian insect fauna

The carabid beetle Pterostichus (Phonias) strenuus (Panzer) is newly recorded from Iran. It was collected by hand from Ghaleroudkhan forests in the Caspian province of Guilan. This carabid beetle is widely distributed throughout the Palaearctic region including Europe, Uzbekistan, Kazakhstan and Russian Far East.

Faunistic study of the family Ichneumonidae was carried out between 2009 and 2012 in the central parts of Caspian province of Mazandaran. We used Malaise trap, window trap, yellow and white pan traps, light trap and insect net for collecting the ichneumonid specimens The species Stilbops vetulus (Graven horst, 1829) and the subfamily Stilbopinae are newly reported from Iran.