Iranian Journal of Forests and Rangelands Protection Research
Year:2011 | Volume:9 | Issue:1 (17)|Papers Count:9

Hyphantria cunea Drury (fall webworm moth) is an important forest pest in Guilan province. Larval damage of the insect sometimes leads to severe host tree defoliation which in turn calls for drastic control measures. The objective of this study was to determine pathogenicity of four isolates of Beauveria bassiana and one isolate of Isaria farinosae on 4th larvae (2-days-old) of Hyphantria cunea. Susceptibility of different instars of this insect was also studied against the isolate having the highest percent mortality. Bioassay tests were conducted in the form of factorial and completely randomized design with 30 treatments and four replications. Ten larvae were topically infected with fungus spores. The control larvae were treated with distilled water plus Tween 80 0.03%. Results showed that Fashand isolate caused the highest percent mortality (39%), whereas 1872c was second in importance. LD50s of the above three isolates were 0.2×103 (6.6×103-6.9×104), 9.5×105 (0.3×105-4.9×106) and 7.8×106 (1.5×106-0.2×107) conidia/ml., respectively. Susceptibility of different larval instars was varied too. Second and third instars had the most mortality rate (57 and 51%) respectively. In 108 concentrations Fashand caused the 85% mortality.

This study was conducted in Tahlijan plantation near Shahrekord in autumn and winter climatic conditions in a given year. Seeds of two species, Ash (Fraxinus rotundifolia) and tree of heaven (Ailanthus altissima) were collected from selected trees and examined by Tetrazolium chloride and dormancy breaking tests (cold stratification for 3, 5 and 6 weeks). In order to investigate effect of different treatments on dormancy breaking and germination in the first step, each treatment as well as control were cultured in vitro in 4 replicates of 50 seeds, then the germination percentage and speed was measured. In the next step the effect of wintering on seeds germination was examined under 5 treatments, 1) scattering the seed on the soil surface 2) shallow burial, 3) plastic cover, 4) wire mesh-cage and 5) crystal jars by 16 replications inside and outside of water gutter in forest plantation. Following winter period these treatments were collected and the seeds viability was evaluated and compared with the first stage results. Germination percentage under 6 week’s stratification for ash and tree of heaven were 59.93 and 15.14, respectively. Seed germination percentage and speed- inside and outside of the water gutter- did not show any significant differences. The highest germination percentage was observed in shallow burial for Ash (53.35%) followed by crystal jars for tree of heaven (34.05%). Shallow burial treatment caused break seed dormancy break of Ash and an increase in speed of germination (p<0.05). Seed dormancy break did not occur in soil surface treatment in which seeds were treated naturally.

Thyme (Thymus spp.) is a medicinal and aromatic plant which grows in most temperate regions. Presently 14 Thymus species are reported from Iran and six have so far been collected and reported from Hamedan province. These include, T. daenensis, T. fallax, T. kotschyanus, T. pubescens, T. migricusand T. eriocalyx. Based on thyme distribution in the province, diseased samples together with associated pests were collected and transferred to the laboratory. Thyme plant distribution areas were regularly visited and sampled during 2008-2010. Several samples of pests and diseases on Thyme plants were collected. Insect pests collected on different thyme species are as follows: thyme aphid, Aphis serpylli on T. daenensis, T. fallax, T. kotschyanus, T. vulgaris, Leaf Miner beetle, Apteropeda sp. on T. daenensis, T. fallax, T. kotshyanus and Thrips tabasion all Thyme species. Fungi diseases separated from diseased thyme plants of the province are, powdery Mildew Golovinomyces biocellatus on T. daenensis, T. fallax, Rust Puccinia serpyllion T. daenensis. Parasitic plant, (Dodder) Cuscuta aproximata collected on T. daenensisand T. fallax species.

In the course of the survey of insect fauna associated with forests and rangelands of Iran (1993-2003) and the collections made in the period 2004-2007, the fauna of cetonid beetles were investigated. Specimens were mainly collected by banana trap and direct hand. Following transfer of insect specimen to the respective laboratory, preliminary identifications were carried out using diagnostic keys as well as close cooperation of the third author who determined or confirmed the identifications. All specimens together with relevant localities are currently maintained in arthropod museum of Research Institute of Forests & Rangelands. A total of 15 species were identified as follows. The species Netocia persica Kraatz, 1886 is collected and identified for the first time from Golank, Ramiyan and Tange Gol of Golestan province as well as Chehel-Dokhtar on the border of Semnan and Golestan provinces. The other species are mainly collected for the first time from the mentioned localities.*Species living in forests (collected in banana traps), larvae feeding upon decayed trees.·Species not coming to banana traps or rerely, living in open areas, larvae larvae feeding upon roots of chardacea.*Cetonia aeratulaReitter, 1891*Cetonischema speciosa (Adams, 1817)*Eupotosia affinisssp. Pseudospeciosa Miksie, 1957·Netocia excavata (Faldermann, 835)·Netocia hungarica ssp. armeniaca (Menetries, 1832)·Netocia hungarica ssp.ignisternum Reitter, 1891·Netocia hungarica ssp.pseudoviridiana Medvedev, 1964·Netocia persica Kraatz, 1886·Netocia schekovnikovi Zaitzev, 1917·Netocia trojana ssp. godeti (Gory & Percheron, 1833)*Netocia viduassp. asiatica (Falderman, 1835)*Oxythyrea cinctella(Schaum, 1841)*Potosia cupreassp hieroglyphica (Menetries, 1832)*· Potosia funebris (Gory & Percheron, 1833)

Many species of spurges (Euphorbia spp.) are scattered in the pastures of East Azarbaijan province. The genus Euphorbia L. (Euphorbiaceae) typically have poisonous white sap in all plant parts. In this study defoliators of two common species of spurge including Euphorbia seguieriana Neck and E. heteradenia Jaub & Spach were collected and identified in Tikmedash and Horand rangelands, respectively. Two species of sphengid moth's including Hyles lineata (Fabricius) and Hyles euphorbiae L. in Horand and the leafy spurge defoliator moth, Simyra dentinosa Freyerin in Tikmedash were detected as potential biological control agents of spurge. Study on natural enemies in laboratory rearing larvae of moths indicated that the larvae and pupae parasitized by three species of parasitoids as follows:1-Cotesia vanessae Reinhard (Hym., Braconidae) 2-Hyposoter didymator (Thunberg) (Hym., Ichneumonidae) 3-Masicera sphingivora (Rohineau-Desvoidy) (Dip., Tachinidae) The larvae of S. dentinosa were parasitized by the first two species of parasitoids and pupae of H. lineataand H. euphorbiae were parasitized by the tachinid fly.

Recent drought stresses and subsequent trees physiological weaknesses had drastic effect on borer beetles population increase in Zagros forests. Shalam forests located in Ilam province was selected to investigate borer beetle infestation rate of forest trees to the under various site conditions and stand structure in Persian oak forests. The study area was divided into 20 units using GIS and random systematic sampling and 3 1000m2 circle plot in any single unit was established across the landscape. In each plot, tree diameter (DBH), mean crown diameter, source and form of trees and shrubs, crown dieback condition, borer infestation rate and site situation was measured. Results showed that topographic factors and stand characteristics have significantly affected contamination rate of forest trees to borer attack. The highest contamination percent of trees to the borer beetles was observed southward in 1700-2000 m elevation from sea level. There were positive correlation between elevation and beetle's infestation. Slope did not show any correlation with amount and intensity of beetle's contamination. Abundance of beetles was higher in coppice stands than standard trees. With increase in stand density and tree crown width, beetle's intensity increased. Contamination intensity was higher in smaller diameter classes as well as in dieback prevalent stands. The results emphasized that borer infestation usually occur following severe droughts and drying and thus borer beetles are considered as secondary agents causing tree mortality. The results indicated that site and stand diversity affect borers' infestation rate. Thus we can pinpoint the hotspots and apply appropriate measures for forest protection.

In order to evaluate seed source and pre-treatment hydrogen peroxide on the seed germination characters of Fagus orientalis Lipsky, some seeds were collected from three altitudes (600, 1200, 1800 m a.s.l.) in Vaz forests of Noor city (north of Iran). Following soaking in hydrogen peroxide (20 and 40 minutes) seeds were stratified together with the control in moist sand and maintained in refrigerator for 120 days. Germination initiation was recorded every week. The results showed that seed dormancy of 1800 m elevation took 60 days long which was longer than the other two seed sources. Seed source significantly affected seed germination, whereas seed germination rate, mean daily germination and germination speed increased with increase in altitude. Hydrogen peroxide did not increase seed germination as well as daily germination mean. This research revealed that to break dormancy of higher elevations seed, the longer stratification period is required. Considering applying stratification, control seeds of higher elevations had higher germination rate compared to the seeds of lower elevation. Thus it is advised to use seeds from higher elevations for seedling production in mountain nurseries and seed sowing or seed broadcasting for restoration of deforested or non-regenerated areas of Caspian mountain forests.

Prangus ferulaceaL.is a prennial plant widely distribute in Zagros Mountains, especially in Chaharmahal & Bakhtiary province. Further to fodder and medicinal values the plant can help to control soil erosion through its deep root system (Moghimi 1384). This species is infested by a diverse group of insect pests include stem borers, defoliators and in particular seed bugs which collectively threaten its survival. In the course of surveys conducted to collect and identify seed affecting pests of Prangus ferulacea L, in 2009-2010, premature to fully formed seeds were collected, counted and examined for wasp infection percentage. To collect adult wasp, seed samples were stored in glass jars in the laboratory and the emerging adults were kept in 70% alcohol for identification. The results revealed this wasp as Bruchophagus abnormis Zerova 1984. It has been recorded previously only on Trigonella arcuata C.A.Mey in Kazakhstan (Zerova, 1988). Exit holes of adult insect are round in appearance on infected seeds. Seed damage averaged 8-13percent. Further to P. ferulacea, the wasp was collected from Rumex ponticus E.H.L. Krase seeds as well. The collected specimens are presently maintained in the Agricultural and Natural Resources Research Center of Chaharmahal & Bakhtiary in Shahrekord. This is the first report of the wasp for Iranian insect fauna.

Low forest cover and the neccessity to protect and conserve, could not afford to harvest and supply wood for associated sectors in the country. Thus to meet the growing demand for various wooden materials, it seems inevitable to import wood from abroad. Wood in ported from Russia is mainly conducted through Anzali and Astara harbours in Guilan and Nowshahr and Amir-Abad in Mazandaran provinces. Quarantine pests and diseases conveyed to Iran is one of the prime concerns in the context of timber trade. In the period 2007-2009 a research project was conducted to investingate timber-imported pests and diseases in the aforementioned harbours. In this project a number of bark beetles of Scolytidae family were collected on imported timber. Two species were identified as Pityogenes chalcographus (Linnaeus, 1761) and Hylurgops palliates (Gyllenhal, 1813) by Ake Lindelow in Department of Ecology, Swedish University of Agriculture science. These two species are new for fauna of Iran. the specimens are maintained in Arthropod Museum of Research Institute of Forests and Rangelands.