نشریه نامه انجمن حشره شناسی ایران
سال سی و پنجم شماره 3 (پیاپی 60، پاییز 1394)

The members of genus Orius are known as natural enemies of many of plant pests in the world. We studied the fauna and biodiversity of the family Anthocoridae bugs in different environmental conditions of Kohgiloyeh and Boyrahmad province of Iran. Sampling took place in three climates and from three ecosystems (gardens, farms and virgin uncultivated lands) throught three replicationsevery other week. Species were identified based on male genitalia, and the biodiversity study was done using Shannon-Wiener dominance index through SDR software. The species Orius albidipennis (Reuter), O. niger (Wolff), O. laevigatus (Fiber),O. pallidicornis (Reuter),O. vicinus (Ribaut), O. horvati(Reuter) were identfied. The results showed that O. albidipennis was the dominant species in tropical climate and O. niger was the dominant species in cold climate. The Shannon-Wiener indices of tropical, moderate and cool climates were 1.245, 1.233, and 0.9896 respectively. Biodiversity of Orius spp in non manipulated ecosystems were significantly higher than manipulated (agricultural) ecosystems. Therefore biodiversities of the natural enemies were significantly affected by climate and ecosystem conditions.Regarding the side effects of ecosystem manipulating treatments on the biodiversity of the predatory bugs, some conservative treatments such as multi-cropping, rgeen islands of weed could enhance biodiversity and efficiency of predators.

The coccinellid Oenopia conglobata contaminata (Menteries) is one of the most important predators of orchard pests in Iran. The effect of eggs of Sitotroga cereallela Olivier (Lep.: Gelechiidae) and Ephestia kuehniella Zeller (Lep.: Pyralidae) on development and survival of this beetle was studied and compared under laboratory conditions (five constant temperatures i.e., 22.5 ± 1, 25 ± 1, 27.5 ± 1, 30 ± 1 and 32.5 ± 1 °C 55 ± 5% relative humidity (R. H.) and a 16:8 h light: dark photoperiod). Total developmental time at the above-mentioned temperatures were 28.83 ± 0.17, 24.52 ± 0.37, 21,39 ± 0.21 17.92 ± 0.16 and 18.22 ± 0.29 days on S. cereallelaand27 ± 0.38, 23.32 ± 0.14, 19.57 ± 0.28, 16.14 ± 0.17 and 16.33 ± 0.05 days on E. kuehniella. The lower developmental thresholds (T0) of egg, larva, pupa and egg to adult on E. kuehniella were estimated15.02, 8.6, 7.48 and 8.55 ºC and the thermal constant for these periods calculated as 38.16, 222.22, 71.9 and 370.37 DD. The lower developmental thresholds on S. cereallela were found to be 13.79, 5.6, 5.82 and 6.54 ºC andthermal constant for the mentioned periods were 41.15, 277.77, 91.7, 454.54 DD, respectively. Although significant differences between developmental times at different temperatures exist, no significant differences was observed between 30 and 32.5 °C for two prey species. The results suggest that E. kuehniella serves as a more effective host than S. cereallela for rearing of coccinellid O. conglobata.

The corn stem borer, Sesamia cretica Led. (Lep.: Noctuidae),is the most important pest of maize and sugarcane throughout the world including Iran where its egg parasitoid wasp, Telenomus busseolae Gahan (Hym.: Scelionidae) is widely used in biological control programs. Due to the host specificity of the parasitoid wasp, S. cretica serves as the single host for the mass rearing of T. busseolae at the laboratory or insectarium. The present work was intended to find the optimum temperature and photoperiod for the reproductivity of S. cretica at laboratory condition. We evaluated the percentage of fertilized eggs, oviposition rate, peak of egg laying and adult longevity of S. cretica. Thermal treatments and photoperiod treatments included 24, 27 and 30 ºC as well as 24D, 12D: 12L, 8L: 16D (short day period), 16L:8D (long day period) hours respectively. The best temperature for oviposition was calculated between 24 and 27 ºC, but the rate of oviposition was significantly decreased at 30 ºC. Temperature and photoperiod had no effect on the percentage of fertilized eggs and adult longevity. Different photoperiods caused significant effect on the rate of oviposition and the highest oviposition rate occurred in 12L: 12D hours and in 16D:8L hours. The lowest rate of oviposition was observed in 24D period. The highest rate of oviposition occurred on the second day.

New formulations of botanical insecticides have been developed as an effective and safe compound alternative to synthetic pesticides. Application of nanoencapsulated formulations of pesticides enhance efficiency, quality and controlled release of these substances. In this research, insecticidal activity of essential oil of wormwood sagebrush Artemisia sieberi Besser was investigated on various stages of elm leaf beetle Xanthogaleruca luteola (Müller). The experiments were conducted at 25 ± 2 °C, 65 ± 5% RH and a photoperiod of 16: 8 h (L: D). The formulated essential oil was sprayed on leaves and insects simultaneously. The LC50 value of the formulation was 5279, 3939 and 5169 ppm for eggs, larvae and adults, respectively. Treatment of leaves by nanoencapsulated oil at 3000 ppm caused significant reduction at larval stage compared to control. Our findings suggest that the use of nanoencapsulated essential oil can be effective in the management of elm leaf beetle.

The use of modified crop plants through gene transfer between different plant species plays an important role in pest control programs. We have investigated the insecticidal properties of two lines of tobacco transgenic plant consisting of IRIP (expressed with type 1 ribosome inactivating gene) and IRA (expressed with type 2 ribosome inactivating gene) against beet armyworm, Spodoptera exigua Hübner (Lepidoptera: Noctuidae) and tobacco aphid, Myzus nicotianane Blackman (Hemiptera: Aphididae). The transgenic tobacco plants expressing IRA increased mortality and decreased reproduction rate of tobacco aphid. The reproductive period of tobacco aphid fed on transgenic tobacco plant expressing IRA reduced in comparison with the control and IRIP. We did not observed any impact on reproduction parameters of the aphids treated with IRIP plant in comparison with control. Feeding second instar larvae of S. exigua on transgenic tobacco plant expressing IRA led to about 33.3% mortality. Weight of larvae and pupae as well as the rate of the emergence of adult S. exigua were significantly decreased in larvae fed on IRA in comparison with control. These results suggest that type-2 ribosome inactivating proteins serve as significant insecticidal factors on both insect pest and can be used in integrated pest control programs.

In this study, two-sex life tableparameters of Ephestia kuehniella (Zeller) were studied on seven cultivars of barley (Dasht, Khorram, Sahra, Reihan03, Fajr30, 5shoor and EH-83-7) and two cultivars of wheat (Bam and Sepahan) at 25 ± 1 °C, 65 ± 5% R.H., and 16:8 (L: D) h. The shortest and the longest larval periods were recorded on Reihan03 (42.58 ± 0.69 days) and EH-83-7 (53.42 ± 0.95 days) cultivars respectively. The longest and the shortest developmental periods for E. kuehniella were found on EH-83-7 (72.12 ± 1.61 days) and on Sepahan (58.19 ± 1.00 days) cultivars respectively. The heaviest and lightest pupaewere observed on Sepahan (21.07 ± 0.77 mg) and Fajr30 (15.20 ± 0.58 mg) cultivars respectively. The intrinsic rate of increase and net reproductive rate were the highest (0.07 ± 0.00 day-1 and 87.41 ± 1.89 offspring, respectively) on Sepahan, and the lowest (0.037 ± 0.00 day-1 and 12.29 ± 0.48 offspring, respectively) on Dasht cultivars. The results indicate that Sepahan wheat cultivar is the most suitable cultivar for the laboratory rearing of E. kuehniella.

The alfalfa weevil (Hypera postica Gyll) is a serious pest that adversely affects alfalfa forage yield and completely destroys the harvest in the early season every year. In this study, we evaluated the mechanisms of antixenosis, antibiosis and tolerance of 16 genotypes obtained from the screening field, between 18 and 27 °C in April and May 2014 in a completely randomized design with four replications at the greenhouse condition. The rate of expressed proteins and their differences within genotypes were analyzed using SDS-PAGE method. The trichome density and leaf chlorophyll content and their impact on the quantity of weevil larvae were evaluated. We used Mantel test to determine the correlation between greenhouse features and data from one-dimensional SDS-PAGE electrophoresis. No significant correlation was observed between the traits in the greenhouse and molecular data. Using ward method, the studied genotypes were divided into three groups: resistant, moderately susceptible and susceptible. The genotypes "Mahali-Bami", "Talents 2"," Hamadani 106" and "code 108" can be further investigated in the future for their potential resistance to alfalfa weevil larvae.