Applied Entomology and Phytopathology
Year:2002 | Volume:69 | Issue:2|Papers Count:16

Antifreeze protein with thermal hysteresis activity was extracted and purified from adults of Eurygaster integriceps that have been collected trom altitude of Ateshgah Karaj, Iran during winter, and compared with the summer one. Isolation was carried out by using ethanol fractionation, DEAE ion-exchanger chromatography and also more purified with SephadexG-100gel filtration.The puritied protein was also analyzed on SDS polyacrylamide gel electerophoreses for determination of molecular weight. It shows that the molecular weight of this protein is about 19000dalton and its thermal hysterises activity was 4.4°C at concentration of 50 mglml. This protein was absent in summer samples. Therefor, it is suggested that antifreeze protein in winter sample may be an important function in survival of E. integriceps during winter season.

Survey of oribarid mites resulted identification of 10 species, 12 genera and 7 families belonging to the Poronotic Brachypyline Oribatids cotton fields of Moghan Plain in 1996. The families, genera and species of Mochlozetidae: Mochloribatula multiporosa Mahunka, 1978; Mycobatidae: Mycobates austroamericanus Hammer, 1958, Punctoribates manzanoensis Hammer, 1958; Oripodidae: Exoribatula sp. and also the genera and species of Allogalumna sp. Grandjean. 1936 (Galumnidae): Wooleybates dactyloscopica (Balogh et Mahunka, 1968), Oribatula gracilis (Hammer. 1961). Zygoribatula bonairensis Willmann. 1938 (Oribatulidae); Passalozetes proll1inens Balogh ct Mahunka. ]968 (Passalozetidae); Xylobates antilensis Mahunka, 1985 (Xylobatidae) are new records for Iran and the genera and species of xylobates capucinus capucinus Berlese, 1908 and Zygoribatula connexa (Berlese 1904) are new for the Meghan Plain region. The families Oribatulidae and Galumnidae with 4 and 1 genera had the highest and lowest diversity, respectively.

The Cydia pomonella granulovirlls (CpGV) is a very effective biological control agent against codling moth, Cydia pomonella L. (Lep.: Tortricidae). Its isolation from natural populations of codling moth is difficult and only a few isolates have been described in the world, because diseased larvae usually rupture and disintegrate and can not be found on the trees. So, in this survey, lots of corrugated cardboard trap bands were placed around the trunks of apple trees in different regions of Iran and they were surveyed for codling moth larvae infected by CpGV. At least, 11 natural isolates from Northwest and Northeast of Iran were collected and surveyed. Viruses from single or pooled infected larvae were isolated and propagated in the fourth in star larvae of the codling moth. Light and electron microscopy studies confirmed the presence of granulovirus in codling moth populations of the above mentioned regions.

Poplar wooly aphid is considered as one of the most important pests of poplar plantations in the world as well as in Iran. Pest resistant poplar clones have a number of environmental and economic advantages and they are particularly important as a major component of any integrated pests management program. Resistance and susceptibility of eleven poplar clones including ten Populus nigra and one P. alba clones were evaluated to Phloeomyzus passerine at Zanjan-Choob station of Zanjan province in during 1999 and 2000. In 1994, young poplar stands of 11 clones were planted in a complete randomized block design with three replications. Thus the poplar trees were 5 and 6 years old respectively at the time of study. Infested percentage of experimental plots were measured with two methods. The first, all infested trees in each plot were separately counted twice a year (Midsummer and early autumn percentage for each plot were calculated) and wooly aphid infestation recorded. in the second method, in the year 2000, five levels of bark infestation were defined and numerated as follows: 0=0% (with out infestation), I=20% infestation from tree base up to 10 cm stem height. 2= 40% (infestation from tree base up to 50Cm stem. height), 3=60% (Infestation from tree base up to 150 cm. height), 4=80% (infestation from tree base up to ISO cm.height), 5=100% (infestation over 150 cm. height including side branches). Meanwhile means infestation for each plot were measured accordingly.Data obtained for each year were transferred to √X+0.5 and separately analyzed. The analysis of variance conducted with MSTATC software showed a significant difference among tested clones. LSD Test Method indicated P. n. 42/78 and P.n.42/51 (from Karadj) as susceptible clones and P. n 62/154 (fromTurkey) and P. alba 58/57 (from Italy) as resistant clones. Results obtained in the tirst year were contirmed by the two sampling methods used in the second year. P. nigra 65/71 (Soltanieh origin) was found relatively resistant.

In order to compare the effects of four conventional insecticides for controlling, alfalfa weevil Hypera postica, on mortality and longevity of parasitoid Bathyplectes curculionis (Thompson), a laboratory investigation has been carried out in a RCBD design with 9 treatments and 3 replicates.The parasitized larvae of alfalfa weevil treated with following insecticides: [Check, treated with water (t1 )], chlorpyrifos 0.1% (t2), chlorpyrifos 0.2% (t3), etrimfos 0.05% (t4). etrimfos 0.1% (t5), malathion 0.15% (t6). malathion 0.3% (t7), phosalone 0.125%(t8) and phosalone 0.25% (t9).According to IOBC/ WPRS classification, t7 which caused 89.7% mortality was the most and t2 caused 31.4% mortality was the least harmful insecticides for larvae of parasitoid, when it was present in its host. The percentage of mortality for tl to t9 were 5.7, 31.4, 52.6, 67.5. 83.2, 62.5, 89.7, 50.5 and 65.0 respectively. Longevity offemale parasitoids in these treatments were 1].4, 7.6, 7.5, 7.0, 6.1, 7.0, 6.62, respectively.This study has also shown that there is no significant difference at P=5% among mortality of pest at recommended or reduced dose in t4-t5 and t6-t7, however, significant difference observed for mortality of parasitoid in these treatments.

Thirty six samples oftive maize hybrids including Ksc 301, Ksc 604, Ksc 647, Ksc 711 and Sc704 harvested from corn fields in east of Mazandaran province for two successively years. The samples were analyzed to detect and estimate Aflatoxin B1 B2. G1 and G2 by Romer TLC method. Aflatoxin B1 was detected in Ksc 301, Ksc 604 and Ksc 647 at alevel of 15 and 17.5, 35 ppb respectively in 1998.Aflatoxin B2was also found in Ksc 647 at level of 8.75 ppb. in 1997 Aflatoxin B1 was only detected in Ksc 301 at a level of29.17 ppb. Discolored and damaged corn seeds of the mentioned samples were cultured on PDA and humid filter paper to evaluate fungal contamination. The samples of Ksc 301, Ksc 604, Sc 704, Ksc 647 were contaminated with Aspergillus flavus at a level of 46, 16, 7 and 43% in 1998. Aspergillus flavus contamination was only detected in sample of Ksc301 at a level of 47% in 1997. This is the first report concerning natural occurrence of Aflatoxin in corn samples of iran.

Parasitoid community of grass-feeding nocluid species was studied in north east of England. Twelve species of endoparasitoids were collected. Among them, Glyplapanleles fiulvipes (Haliday) and Cotesia rufrieus (Haliday) were dominant braconid species. Parasitism mostly occurred on over wintering larvae, and as average. 25-40% larvae population was parasitized. Adult parasitoids emerged in April and May. Parasitism level was compared between different areas and for two years. The rate of parasitism was slightly density dependent for two different areas and in two years as shown when regression analysis was carried out.

Sunn pest egg parasitoid, Trissolcus semistriatus (Hym., Scelionidae), was reared on eggs of two species of bugs, Graphosoma lineaturn (Het.. Pentatomidae) (Ts-Gr) and Eurygaster integriceps (Het., Scutelleridae) (Ts-Eu), for two generations. Functional and numerical responses of the two groups were compared.A one day old female parasitoid of the two groups were introduced to 8 density levels (2, 4, 7, 14, 28, 42, 56 and 70) of one day old eggs of Sunn pest, E. integriceps. in 9 replicates for 8 hrs. Experiments conducted at 25± 0.5°C, 45±5% RH and l6L:8D h photoperiod. Type II and III functional responses were shown by Ts-Eu and Ts-Gr, respectively. Ts-Eu had higher searching efficiency (a) and lower handling time (Th) than Ts-Gr. Maximum attack rate (T/Th)reached 63.49 and 20.25 for Ts- Eu and Ts-Gr. respectively. Numerical response ofTs-Eu to cumulative densities of host eggs was linearly increasing, but was domed shape for Ts-Gr.

Using Galleria soil trap, two isolates of Beauveria bassiana have been isolated from soil of Fashand and Atashgah regions of Iran. Preliminary assays showed that, these two isolates together with one isolated from pupae of Red Palm Weevil (Rhynchophorus ferrugineus) in Saravan are pathogenic to Locusta migratoria and some other long and short horn grasshoppers.Bioassays showed that, the lowest LD50 belong to isolate Fashand when using against male insects of L. migratoria numbering 1.32x 103 spore/insect and the highest one scored 3.59x 104 spore/insect in female insects treated with isolate Atashgah. The lowest LT50 recorded at dosage 105 spore/insect of isolate Fashand in male insects.Using a. local odorless kerosene as the carrier of spores had no adverse effect on spores viability and completion of infection in host. Further this carrier checked the limiting dIect of low humidity on spore germination.

During 1998, a survey was carried out to collect and identify terrestrial Parasitengona mites associated with short-horned grasshoppers (Acrididae) in Karaj and Varamin, north- central regions of Iran. Samples of grasshoppers were taken twice a month from these regions. They were examined in laboratory for mites associated with them. In this study three new species of subfamily Callidosomatinae, genus Charletonia Oudemans, 1910 were collected and identitied as follows: The species C. damavandica sp. nov.on Acrotylus insubricus Scop. And Mioscirus wagneri Kitt. From Varamin; C. nazeleae sp. nov. on Heliopteryx humeralis Kuthy and Palasiella turcomana F-W. from Karaj: and C. saboorii sp. novo on Heteracris littoralis similis (Br.-W.) from Varamin. Type specimens were deposited to insects and mites collection, College of Agriculture, Tarbiat Modarres University, Tehran, Iran.

One of the fundamental aspects in integrated Sunn pest management is that to consider economic injury level for appropriate control application. The aim of present study, was to assest quantitative losses caused by Sunn pest on wheat crop in Ghazvin during 1998- 1999. In order to achive the above mentioned goal, were used cages with the dimension 2X 1.5X1.8 meter. Sunn pest quantitative loss assessment was at the ft.amework of factorial test based on randomized complete block design with five replications .The first factor were Alvand and Zarrin wheat varities and the second factor were over wintered adult Sunn pest densities including 0,2,4,6.8, 10, 12.15, 17,20 individual per square meter. The factors involved in assessing consisted of the yield, number of damaged spike and shoot ,the weight of 1000 grains and yield reduction.The ersults of study were as follows : The yield loss mean in over wintered adult densities for Alvand wheat variety included 123.5,80.03,53.5,50.49,45.5,38.28,4087, 41.98,38.66 Kilograms per Hectre and 83.55,68.1,50.67,40.43,44.8,41.26,42.53,43.19,46.18 Kilograms per Hectre for zarrin wheat variety. Results showed that, there was a linear regression between pest population densities and yield reduction. Also there was positive correlation at 1% level between number of damaged spikes and shoots and reduction percentage on Alvand avd Zarrin varieties with adult Sunn pest population densities.

An experimental field was conducted in split plot design with four replications at Kashmar (NE. of Iran) to investigate effects of row spacing on critical were consident as cotton (GossypiumhirsutumL . var. Varamin). There row spaces (60,75 and 100 cm)were main plots and seven treatments of weed free period included 0,3,6,9.12 and 15 weeks after cotton emergence in adition to a check treatment of throught season weeded plot were as supplots. Plant population of all plots was consistent and adjusted to 6.6 plant /m2.Results showed that all mesearud characters in except of cotton height had no effects by row spaces. Howerer the intluence of weed free periods were significant for branch numbers (monopodial and sympodial). plant height. ball numbers (open and closed) and 20 bools weight. According to exponential polynomial equation titted for yield (percent of weed free check plot) vs. weed free periods. the results indicatced that 51 days weeding for 60 and 75 em row space and 70 days weeding for 100 cm row space was necessary to adopt 95% yield of weed free check treatment. Yield (perecnt of weed free check) of 60 cm row space treatment was tending to increase and for 100 cm row space tending to decrease altough all of them were not significant.