Iranian Journal of Forests and Rangelands Protection Research
Year:2018 | Volume:16 | Issue:1 (31) |Papers Count:10

In recent years, widespread tree dieback simultaneously with charcoal oak disease have occurred in Zagros forest especially in Ilam province. They dramatically caused damage to oak trees. This research was carried out to identify pathogenic fungi, to prove the pathogenicity and to investigate their pathogenic behavior during 2012-2015 in the forests of Ilam province. After several field observations across the forests of Ilam province, several samples were collected from infected parts of Persian Oak trees and transferred to the laboratory. Then, the samples were cultured to screen the pathogenic agents identified using morphological traits and validated by fungi keys. In order to prove the pathogenicity of the identified fungi, they were inoculated on two-year-old oak seedlings. In the final stage, the pathogenic behavior of fungi was studied. The results showed that fungi causing charcoal diseases in the forests of Ilam province were Biscogniauxia mediterranea and Obolarina persica. Furthermore, the fungi caused the disease on oak seedlings with dieback symptoms on the sections areas above the inoculum site. The study of the pathogenicity behavior of these fungi showed that their contamination began from inoculation site and developed in the wood, in addition to longitudinal extension, the hyphae colonized in transverse and radial directions towards the heartwood, so that it affects the xylem and phloem vessels. Considering the pathogenicity prove of these fungi and their contribution to the weakness and dieback of Persian oak trees, it would be possible to reduce the oak losses by eradicating the dead trees to prevent fungal spore spreading in the region.

The scale insect, Kermes quercus (L. ) specifically feeds and damages oak trees. This pest was studied during 2015-16 in the forests of Gilan-e-Gharb, west of Iran on the Persian oak (Quercus brantii). The biological stages of the pest were collected from the infected branches and in the laboratory, under a stereomicroscope, the counting was recorded and the population fluctuations were plotted as a curve. Also, spatial distribution and population fluctuation were calculated using Taylor's power law models and the Iowa’ Index. The results showed that this insect, with respect to the average temperature and relative humidity of the region, has one generation per year and two nymphal stages. It overwinters as second instar nymph stage on the trunk and branches of oak trees. Young females appear in early April, and after three weeks of the growth of the ovaries, the females become bulky and glabrous. The oviposition period lasts from late April to late May for 20-30 days. The adult insects die 20 days after oviposition. The eggs in the sub-body cavity gradually become hatched and the first instar nymphs exit from the end of the body in late May and early June, and the egg shells remain in the body of the female's insect. The length of the overwintering second instar nymphs is approximately 10-11 months, from late April to early May of the following year.

Loranthus europaeus, a semi-parasite plant, is one of the main factors in depredating Zagros forests. It is distributed and grown by seed via birds. In order to study the oak infection induced by L. europaeus, the present study was conducted in the forest of Heydarbaighi village, Gilan-e Gharb, Kermanshah. For this purpose, 100 plots with 10 Ar area were applied based on systematic-random method in a 100*200 m survey network for 200 ha. The species type, DBH, tree height, crown diameters, and infectious rate induced by L. europaeus were measured based on DMR in three parts of tree crown. The results revealed that among nine tree species, Quercus brantii covered 77. 5% of all trees. The results of ANOVA showed a significant effect of L. europaeus on classes of DBH, height, and crown area (P≤ 0. 01). Duncan test confirmed the significant difference of infectious rate of L. europaeus in quantitative parameters. The infectious rate of L. europaeus increased by enhancing tree quantitative parameters such as DBH, height, and crown area. The highest infectious rate was observed in 45 and 50 cm DBH, 9 m height, and 15 m2 crown area. Our study suggests that the infected trees with high quantitative parameters should be first considered to control the L. europaeus than others.

Erysiphales are a group of biotrophic fungi, affecting a wide range of monocotyledonous and dicotyledonous plants. These Fungi have a global distribution, the fungi and their hosts’ distribution varies in different regions of the world. In this research, a group of infected plants was collected from Oshtran Kouh protected area in Lorestan province. After microscopic studies, six species of fungi were identified from 12 plant hosts. The fungus of Leveillula taurica on Silene chlorifolia, Dianthus macranthoides, Silene casarea, Achilea tenuifolia, Seratula cerintifolia and Scariola orientalis; Leveillula brauni on Eryngium noeanum; Leveillula duriaei on Euphorbia virgate; Leveillula lanata on Teuchrium orientale and salvia multicaulism; Golovinomyces cynoglossi on Myositis palustris and Podosphaera dipsacacearum on Pterocephalus plumosus were identified. The report of these fungi from the plants of Silene cholorifolia, Dianthus macranthoides, Silene casarea, Achilea tenuifolia, Seratula cerintifolia, Scariola orientalis, Teuchrium orientale, Salvia multicaulis, Eryngium noeanum and Euphorbia virgata, the first report of the world, and the reported fungus from Pterocephalus plumosus is the second report from the world and the reported fungus on Myositis palustris host is the first report from Asia and Iran.

National Botanical Garden of Iran (NBGI) includes endemic and exotic plants that besides a source of plant genetics, it is considered as a wealthy source for research and education of botany in Iran. The plant parasitic nematodes in some collections including Hyrcanian habitat, Zagros habitat and Medicinal and aromatic garden were studied by collecting soil and root samples from trees, shrubs and annual plants. The nematodes were identified based on morphological and morphometric characters and based on these characters 34 species belonging to 19 genera were identified. Pratylenchus spp. with four species, followed by Helicotylenchus, Meloidogyne and Paratylenchus each one with three species were the more frequent genera. The species of Tylenchidae family showed higher frequency and multiplicity in Medicinal and aromatic collection. Due to infection of Brant’ s oak (Quercus brantii Lindl. ), oak manna (Q. infectoria Oliv. ), Pistacia atlantica and a few of medicinal plants to some species of plant parasitic nematodes i. e. Root Knot Nematodes, Root Lesion Nematodes, Ring and Dagger Nematodes, establishment of new plots with the seedlings free from the plant parasitic nematodes is emphasised. Cephalenchus daisuce, Coslenchus capsici from Hyrcanian habitat and Paratylenchus ciccaronei from Medicinal and aromatic garden are new records from Iran.

Fire is one of the main causes of carbon emission from forest stands. Therefore, the present study was conducted to investigate the amount of carbon emission caused by fire in the loblolly pine plantations in the Takhsam region that located in area of Lakan city of Guilan province. For this purpose, a burned region with 5 hectares’ area and a control region next to burned stand were selected and 5 circle sample plots with 4r (400 square meters) areas were accomplished in two stands by random-systematic method and trees diameter at breast height and total height in sample plots were taken. Then, by investigating the conducted studies Finally, 5 models selected to calculate the trees biomass in two stands. According to the results of this study, the average of trees biomass in the control stand was estimated between 93086. 98 (P model) to 10536. 9 kg/ha (model M) and the average of trees biomass in the burnt stand was estimated from 67829. 73 (P model) to 83509. 04 kg /ha (model M). The results of this study also showed that the carbon stock content in the control and fired stands was 48. 853 and 38. 357 tons per hectare respectively which showed significant difference in t-test. The amount of carbon emissions from the fire was 10495. 69 tons per hectare and the total carbon emission at the surface of the fire spot was about 52. 478 tons. Among the selected models, P model (BD = β 0 +β 1(DBHβ 2)) provided the least standard deviation in the calculations.

During the studies on identification of biological control agents for box tree moth (Cydalima perspectalis Walker, 1859) in Hyrcanian forests, a fly, Compsilura concinnata (Meigen) (Diptera: Tachinidae) was collected from Cheshmeh-Bolbol Box reservoir, located in Golestan province, in spring of 2017. This is the first report of fly parasitoids (Compsilura concinnata) of Box tree moth from Iran.

Several species of the genus Bruchophagus Ashmaed, 1888 (Hym.: Chalcidoidea, Eurytomidae) feed on seeds of pasture and medical plants and cause damage to these plants in rangelands. During 2011-2017, seeds of different plant families (Asteracae, Apiaceae, Campanulaceae, Caryophyllaceae, Ephedraceae, Fabaceae (Leguminosae), Lamiaceae, Scrophulariaceae and Zygophyllaceae) were collected from rangelands of Qom province, central Iran. Emerged wasps from seeds were collected and identified. These species were obtained from 15 host plant species among which 10 are new host plants for these Bruchophagous species. Plants that appear as new reports are marked with an asterisk: B. astragali Fedoseeva, 1954: *Astragalus compylorrhynchus Fisch. & C. Mey., *A. brachyodontus L., *A. iranicus Bunge, *A. oxyglottis Bunge; B. dahuricus Zerova, 1992: Dorema ammoniacum (D. Don. ); B. gibbus (Boheman, 1836): Trifolium pratense L., D. ammoniacum (D. Don. ); B. kononovae Zerova, 1994: *A. brachyodontus L., *A. compylorrhynchus Fisch & C. Mey.; B. medicaginis Zerova, 1992: *Medicago lupulina L., *M. sativa L.; B. mutabilis Nikolskaja, 1952: *A. oxyglottis Bunge; B. roddi Gussakovsky, 1933: M. sativa L.; B. trigonellae Zerova, 1970: *Trigonella monantha Boiss & Hohen; B. turkestanicus Zerova, 1994: D. ammoniacum (D. Don. ).

Wild almonds are valuable species with broad ecological ranges and high genetic diversities for reforestation in Zagros forest. Therefore, for identification pests affecting these valuable species, the current research carried out between 2014-2015 in Chahar Mahal and Bakhtiyari province. Megophthalmus scabripennis species had severe damage on Amygdalus haussknechti shrubs. To study the population dynamics of the pest, twelve shrubs were randomly selected. In each sampling date, the number of leafhopper at each stage was counted in four netting. For study the leafhopper biology in Tomanak-Ben region, three weeks prior to emergence of overwintered adults, sampling nets were placed on infested trees. The results indicated that pest overwintered as adults. These adults oviposited in spring and their nymphs hatch out of the eggs and go through five instars. This leafhopper had three generations in a year in this region. The abundance peak points of adult insects were in the end of May, early of July and October for all three generations, respectively.

The pit scale insect, Asterodiaspis quercicola (Hem: Asterolecaniidae) is restricted to oak tree, Quercus brantii and it is now prevalent in Zagros oak forest region. The biology of this pest in natural conditions was investigated on Quercus brantii (Fagaceae) during 2015-2016, for the first time in Iran (Ghalajah forests, West Islamabad). The results of this study showed that this insect is a univoltine species and overwintered as pre-reproductive female. Eggs begin to hatch in the middle of May. After one week, the crawler dispersal takes place. The egg population pick is in early July and declines in late July. The incubation and nymphal period take 23± 1 and 92± 2 days in average, respectively. Egg incubation time plus nymphal period take 115± 1 days and the adult longevity is 53± 2 days. The reproductive female starts to egg laying early April, and ends on the early August. The adult females develop through two nymphal stages; the first and second nymphals stages emerge in the late May and late June, respectively; this period lasts to the end of September. Meanwhile, the population pick of egg, first instar, second instar, pre-and post-reproductive female appears on early July, mid-July, mid-August, end of September and mid-May, respectively.