JOURNAL OF ENTOMOLOGICAL RESEARCH
Year:2015 | Volume:6 | Issue:4 (24)|Papers Count:8

The diamondback moth, (DBM) Plutella xylostella (L.) (Lep.: Plutellidae) is one of the most important pests of cruciferous plants throughout the world. In this research the efficiency of different common insecticides (Indoxacarb, Thiodicarb, Hexaflomoron) with or without adjuvants (Bar-TarÒ, DGÒ) on the third instar larvae of DBM was investigated. Results showed that 50% lethal concentration (LC50) for Indoxacarb, Thiodi carb and Hexaflomoron on 3rd instars larvae with significant difference were 46.79, 543.12 and 6.22 ppm respectively. Also, the results showed that there were significant differences among different insecticides. between applied adjuvants, . Bar-tar had the higher percentage of usage dose in insecide reduction.

Sugar cane spider mite (Oligonychus sacchari) is one of the major pests of this field crop in Khuzestan province. In concern to reduce environmental side effects of acaricides. an investigation was carried out to evaluate effectiveness of two consequent water spray, once water spray+once Abamectin applications within 48 hours with single application of fenpyroximate SC 5% against highly populated of active stages of sugarcane spider mite (Oligonychus sacchari) on two susceptible cane varieties (CP48, CP57) in Dhbal-Khazaei agro-industry in Khuzestan province during summer months of 2010. Samples were taken one day before and 3, 7, 15 and 25 days after treatments. The effects of water spraying in control of quantities and qualities damages caused by spider mites on sugar cane plants, determined by weighting and counting number of leaves before and after treatments. Henderson-Tilton formula used for analyses of mortalities percent with help of SAS and compared mean of treatments with DMRT method respectively. The highest mean of active mite stages recorded 10.35 on 2cm2 lower part of underside sugar cane leaf and maximum leaves infested% recorded 77.75% for CP-48 variety. Max and Min treatments effects' observed for fenpyroximate and two time water spray on CP-57 and CP-48 var. respectively. Increasing control effects up to 25 days observed for all treatments. Water spraying in control of mite damages increased 74% weight of treated sugarcane plants along with 36% of new leaves formed for both sugarcane varieties. Two consequent water sprays at 24 hours intervals being more effective if applied at initial spider mite population. This method also keeps natural enemies safe and can be use for sustainable sugar cane mite pest control.

The common green lacewing is an important natural enemy used for pest control in greenhouses. It is also very common in many agricultural systems. This insect is a powerful agent in biological control programs because of its wide geographical distribution, high compatibility with different agricultural systems, high searching capability and ease of rearing. In the present study, the lethal effects of some prevalent insecticides were examined on Chrysoperla carnea adults using residual contact bioassays at 26±2oC, 60±10% R.H. and a photoperiod of 16: 8 h (L: D). The results indicated that the order toxicity of insecticides was: Lufenuron< Thiodicarb<Imidacloprid<Thiametoxam. The susceptibility of males was more than females. The estimated LC50 value for thiamethoxam was 8.83 and 73.05 mg ai. L-1, against males and females, respectively. Lufenuron did not show any lethal effects on adults even at doses higher than maximum field recommendation rate for pest control. The results suggested that lufenuron might bea suitable candidate for further research in IPM programs.

The cabbage aphid Brevicoryne brassicae (L.) is one of the important pests of the Brassicae napus. Some natural enemies such as the parasitoid wasp Diaeretiella rapae are active on this pest.The seasonal population changes of the cabbage aphid, was studied on canola by weekly sampling.The aim of this study was to determine peak of cabbage aphid and its seasonal fluctuation and the percent parasitism for ovulated of efficiency of D. rapae. Samples were taken weekly from 20 middle leaves of the plant at the rosette stage and 20 stems at the later stages. The number of adults and nymphs of the aphid were counting the aphids they recorded in prepared tables and the results indicated the maximum number of aphid host was observed in 16 April 2011 and the average population was 259±13.65 aphids (total nymphs and adults) per stem when the weather warmed and reduced pest population the humidity reduced in vegetation of plants. The parasitism activity of D. rapae on this aphid started from early February and average parasitism was14.18±2.98% and maximum 41.33±3.53% that observed in 7 may 2011.

Thrips and aphids are important pests in greenhouses, due to transmitting viruses. Orius bugs have been proved to be effective predators of these pests, especially in greenhouses. One of the most important factors related to efficiency of predators and parasitoids is their functional response, which refers to the change in the number of prey consumed by a predator per unit time, in relation to prey density. The functional response of adult female of Orius albidipennis Reuter to Thrips tabaci Lind and Aphis pomi Degeer were studied in the laboratory conditions (25±2oC, 50±10% RH, 12L: 12D photoperiod), and densities of 2, 4, 8, 16, 32 and 64 adult T. tabaci and A. pomi per petrydish, over 24h. The data provided good fit to Rogers-II functional response model for both preys. Searching efficiency (a) and handling time (Th) were determined 1.517 and 0.068 for T. tabaci; and 1.369 and 0.067 for A. pomi which not significantly different. Finally these results show high efficiency of O. albidipennis for controlling mentioned pests.

This project was conducted to estimate population densities of Oryzaephilus surinamensis in Sayer date palm cultivar based on Spectrophotometer. Results showed that the wave length of maximum absorption for the developmental stages of the egg, larva, pupa and adult of O. surinamensis in Sayer Cultivar were 1214, 1223, 1216. Based on these results spectrophotometer is a perfect method to detect the different growth stages of Sawtoothed beetle on studied cultivar. All regression coefficients of modeles were higher than 0.5 in dicating a suitalle fittling the modeles to data.two samples of llo g was enough for proper evaluation of densities of different stages of O. surinamensis in stored date fruts RV values for four stages were 9.3, 3.3, 3./and 9.5.The relative variatians (RV) for four life stages of the pest were calculated 22.47, 15.31, 15.85 and 19.81 respectively.since in allcoses RVand RNPwere respectively lower than loand 25, the spectrophotometry could be used in applied and research works.

The effects of four plant essential oils of Mentha longifolia, Thymus deanensis, Achillea wilhelmsii and Artemisia hausskenechtii were investigated on adult stage of Tribolium castaneum and T. confusum. The essential oils were prepared using water distillation method. Essential oils were used in five concentrations and five replications. The concentration selected based on primary experiment for each essential oil. Mortality rate of insects were recorded after 3, 6, 24, 48 and 72 hours. Results showed that the longer exposure of insect to essential oil and the higher concentration of essential oil, increased mortality of the two beetle species in all treatments. There was significant difference among mortality effect of the essential oils. The LC50 value of M.longifolia after 24 hours for T. castaneum and T. confosum were 11.59 and 10.67 ml/lair respectively, while the values of LC50 were 89.21 and 99.79 for T. daenensis, 55.40 and 98.71 for A. wilhelmsii and 60.64 and 62.25 ml/lair for A. hausskenechtii, respectively. The least LT50 recorded was in A. hausskenechtii essential oil with 23.10 and 21.10 hours against T. castaneum and T. confusun, respectively. Results showed that these essential oils can be as safe botanical pesticides for control of storage pests.

The fauna of coccinellids (Col.Coccinellidae) was studied in north of Khuzestan provence, Iran during 2010-2011. total of 17 species from 13 genera, 5 tribe and 4 subfamilies were collected and identified. External characters plus characteristics of the male and female genitalia were used in order to diagnose species. Among species collected, six species were new records for Khuzestan province which marked with asterisk (*). Many species were predacious, preying on various species of aphids, mites and coccids. The scientific names of the species according to their subfamilies are as follows.Subfamily: Coccinallinae1-Coccinella septempunctata Linnaeus 17582-Coccinella undecimpunctata Linnaeus 1758*3-Calvia quatuordecimguttata Linnaeus 17584-Hippodamia variegata Goeze 17775-Oenopia conglobata Linnaeus 17586-Oenopia oncina Olivier 18087-Adalia bipunctata linnaeus 1758*8-Propylea quatuordecimpunctata Linnaeus 17589-Psyllobora vigintiduopunctata Linnaeus 1758Subfamily: Chilocorinae10-Chilocorus bipustulatus Linnaeus 1758*11-Exochomus flavipes Goeze 177712-Brumus octosignatus Gelber 1830Subfamily: Scymninae*13-Scymnus aptezoides Capra & Fursh 1967*14-Scymnus pallipes Mulsant 185015-Scymnus syriacus Marseul1868*16-Cryptolemus montrozeri Mulsant 1850Subfamily: Epilachninae17-Epilachna chrysomelina Mulsant 1850