Control of Lymantria dispar L. by biological agents

The experiment on control ofLymantria dispar L by using different kinds of biological measures, including nuclear polyhedrosis virus (NPV) ofLymantria dispar L., BtMP-342, sex-attractant as well as botanical insecticide, was carried out in the forest regions of Inner Mongolia in 2003. Two concentrations (2.632×10⁶ PIB·ml⁻¹ and 2.632×10⁷ PIB·ml⁻¹) ofLymantria dispar L. NPV were sprayed on the 2rd-instar-larvae ofL. dispar and 70% and 77.8% control effect were obtained respectively. BtMP0-342 was applied to the 3rd- and 4th-instar larvae and the control effect was around 80%. The sex-attractant provided by Canada Pacific Forestry Research Center also showed a good result in trappingL. dispar adults. The self-produced botanical insecticide, which was extracted from a kind of poisonous plant distributed in Daxing'an Mountains, China, exhibited a good control result in controlling the larvae ofL. dispar, and 82% mortality was observed when spraying primary liquid of the botanical insecticide on the 3rd–5th-instar-larvae in lab. Foundation item: This paper was supported by Natural Science Foundation of Heilongjiang Province (C0235) and Youth Foundation of Harbin City (0061218024). Biography: ZHANG Guo-cai (1964), male, Ph. Doctor Candidate, associate professor in School of Forestry, Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Song Funan     

Population characteristics ofDendrolims superans in Daxing’an Mountains

Dendrolims superans produced one generation every two years. Large larvae and small larvae exist at the same time. It broke out in Daxiang an Mountains in 1990, and seriously destroyed growth ofLarix gmelini Rupr. In order to controlD superans, the population properties ofD superans were studied from 1991 to 1992, including sexratio, age distribution, pattern etc.. The sex ratio ofD. superans population is ♀∶♂ − 1.06:L. The larvae age distribution indicates that larvae over 5 instar is less than younger larvae under 4 instar in Yongqing forest farm, but the younger larvae under 4 instar is more than larvae over 5 instar in Hanjiayuanzi Forest Farm. The population ofD. superans in Yongqing Farm has been declining. and mereasing in Hanjiayuanzi. Pupae and eggs are mainly distributed in middle and lower crowns layer of trees respeetively account for 66% and 59.5% of total individuals. The pupae in higher crown layer is lightly regular distribution and clumping distribution middle and lower crowns layer of trees. The eggs in higher crown is light clumping distribution and random in middle and low crown of tree. (Responsible Editor: Zhu Hong)     

Bionomics ofBiston betularia (L.) in Daxing’an Mountains forest area

Observations on life cycle, habits and characteristics ofBiston betularia (L.), which is a major pest infecting birch, were made in Daxing’an Mountain forest area, Heilongjiang Province during 1997–1998. In this area, the pest has one generation per year and overwinters as eggs in cracks of the lower part of stem. Adults emerge from mid-July to late August, and the damage of larvae occurs mainly in May and June. Life cycle table ofBiston betularia was given and control suggestions were made in this paper. Foundation item: This paper is part of Key Subject of Birch in State 9th Five-Year Plan. Biography: Sun Fan (1971-), female, lecture in Northeast Forestry University, Harbin, China Responsible editor: Chai Ruihal     

Study on Cytoplasmic polyhedrosis virus onDendrolimus superans

A strain of Cytoplasmic polyhedrosis virus (CPV) was separated from the infected larva during the research of integrated pest management ofDendrolimus superans. The morphology, bioassay, histopathology and field-test for this CPV were studied. The size of CPV is 0.16 μm×1.57 μm and the virion is 16.0 nm×58.1 nm. The L_C50 to the 3rd and 5th instar larva ofDendrolimus superans were 2.81×10⁴ PIB/mL and 7.17×10⁴ PIB/mL respectively. The polyhedrosis were formed after midgut of larva were infected for 72 h. A large amount of polyhedrosis was formed after 144 h. The mortality was more than 82% and average mortality was 84.62% when using 1.17×10⁸ PIB/mL virus suspension to control the pest in field test. The project was supported by the Natural Sciences Foundation of Heilongjiang Province. (Responsible Editor: Chai Ruihai)     

Study on the parasitoids ofPissodes nitidus Roel

A systematic observation and intensive study on the parasitoids ofPissodes nitidus were made in Langxiang and Xin'qing Forestry Bureau in Xiaoing'an Mountain area in 1996–1999, including the diagnosis, life history, biological characteristics ofEurytoma sp. and parasitoid complex ofPissodes nitidus. There were about 70 species of parasitoids onPissodes nitidus, including Eurytomidae, Ichneumonidae and Braconidae etc. Among them,Eurytoma sp. is a dominant species and a braconid,Ipobracon sp. is a subdominant species, and they play an important role in controlling the pest. Biography: HU Chun-xiang (1955-), male, Associate professor in Forest Resources and Environment Collage of Northeast Forestry University, Harbin 150040, P. R. China Responsible editor: Chai Ruihai     

The effect ofDendrolimus superans breakout on growth of trees

The effect ofDendrolimus superans on growth of trees was investigated after the breakout in Shibazhan forest area in 1990. Stem analysis was conducted for determining the tree increment loss. The result showed that the current annual increment for extreme heavily damaged, heavily damaged, moderately damaged and lightly damaged stands is 14%, 39.8%, 64% and 82% of that of the control forest respectively. (Responsible Editor: Chai Ruihai)     

Preliminary studies on the early quality identification ofAuricularia auricular

In production industry ofAuricularia auricular, the varieties quality is most important impact factor on output. For evaluating the early quality of the edible fungus, 9 varieties ofAuricularia auricular (Au9, CF09, CF05, 29, 916, chang10, chang7, Au.Japanese and 8808) were cultured on the medium consists of potato dextrose agar (PDA) and sawdust to test their mycelium growth rate, endurance to high temperature, resistance to mildew, assimilation of nutriment, and resistance to drought. The result showed that the mycelium of Chang 10, CF09, 29 and Au.Japanese varieties had the eminent characteristics such as short lifespan, stronger assimilation of nutriment, and endurance to high temperature and steady growth. These four varieties are determined as superiority varieties ofAuricularia auricular in accordance with the research results. Foundation item: The research was supported by Science Fund of Northeast Forestry University (2004). Biography: Li Ling (1964-), female, Engineer in Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Zhu Hong     

Study on the biological characteristics ofHomalotglus flaminus

Homalotglus flaminus (Daiman) is an important natural enemy of theChilocorus kuwanae. Its biological characteristic, life history, the action style on hosts were studied at Hongqi Forest Farm, Daqing City, Heilongjiang Province from June 1998 to October 2000, in order to controlH. flaminus and raise the control ability ofChilocorus kuwanae toQuadraspidictus gigas pest. The observed results indicated thatH. flaminus has two generation one year in study area, the pupating span is 12.7 d, life span of females and males is 17.6 d and 10.8 d respectively, egg span is 10 d, and the sex ratio of females to males is 1∶3 Foundation item: This paper was supported by Natural Science and Foundation of Heilongjiang Province. Biography: Mpa Ling (1963), female, Ph. Doctor, associate professor in Northeast Forestry University, Harbin 150040, P. R. China Responsible editor: Song Funan     

Influence of main site factors on Fraxinus mandshurica（Oleaceae） plantation

The investigation was carried out on 10-year-old plantation of Fraxinus mandshurica in Mao‘er Mountain Experimental Station of Northeast Forest University.tree height(H),diameter at breast height(D1.3) and the increment of tree height in 5 years (H5),the thickness of humus layer,as well as the soil moisture were measured for the plantation and the growth indexes(H,D1.3,H5) for different site conditions were analyzed.The results showedthat main site factors influencing the growth of Fraxinus mandshurica were soil moisture,gradient and location of siope in order.The growth of Fraxinus mandshurica was better on the middle-or up-slope site than on the down-slope site.Soil moisture and late frost caused by terrain are the main reasons that limit the growth of Fraxinus mandshurica plantation.     

Effects of some materials extracted fromAjuga species on the larvae ofHyphantria cunea and its natural enemies

Six kinds of extracts drawn fromAjuga multiflora andA. multiflora var.brevispicata and A. multiflora var.serotina using methanol and acetone were used in this experiment to test their killing activity to the second instar larvae ofHyphantria cunea and their influence on its natural enemies. The average death rate caused by those extracts on the second instar larvae was 85.70%. The mortality rate caused by the extracts drawn with methanol was from 88.89% to 96.33%, which was significantly higher than that caused by acetone extracts. Those extracts were safe toTrichogramma dendrolimi, Coccinella septempunctata, the natural enemies ofH. cunea. We did not found any evidence shown that those extracts had any influence the emergence and the development ofT. dendrolimi. Those methanolic extracts gotten fromA. multiflora andA. multiflora var.brevispicata had no significant effects on the mortality of the larvae and adults ofC. septempunctata. Those extracts could be used in the control ofH. cunea safely. The research was sponsored by National Nature Science Fundation (39470586) (Responsible Editor: Chai Ruihai)     

寄生小蜂对小青×黑杨树皮及杨圆蚧挥发油的行为反应

Four-armed airflow olfactometer was used to determining the foraging behavior ofPteroptrix longgiclava (Girault) (Hymenoptera: Aphelinidae) andEncarsia gigas (Tshumakova) (Hymenoptera: Aphelinidae) to the essential oils which emitted from the healthy bark ofPopulus pseudo-simonii×P. nigra, the infested bark injured byQuadraspidiotus gigas (Thiem & Gerneck), the body and scale of fixed 1st-instar-nymph ofQ. gigas. The results from these experiments showed that the volatile oils produced from the injured bark and from the scale of fixed 1st-instar-nymph had a higher attractive ability to female adults of the two species of wasps. The essential oil produced from the scale of the pest at dosages of 3–7 μL and the essential oil emitted by injured bark at dosages of 5–9 μL had a stronger alluring effect on the host searching behavior ofPteroptrix longgiclava. The essential oil from the body of fixed 1st-instar-nymph ofQ. gigas also had certain effect on the host locating effort ofPteroptrix longgiclava andEncarsia gigas. Those two wasps did not shown any reaction to the essential oil produced by the healthy bark of poplar. Foundation item: This paper was supported by National Natural Science Foundation of China (39970620) and the “TRAPOYT” Biography: CHI De-fu (1962-), male, Ph.D., Professor in Northeast Forestry University, Harbin 150040, P.R. China Responsible editor: Chai Ruihai     

The use ofBacillus thuringiensis on Forest Integrated Pest Management

Bacillus thuringiensis is a major microbial insecticide and a source of genes encoding several proteins toxic to insects. In this paper the authors give a brief summary ofBacillus thuringiensis used on the integrated pest management in forestry. The derivatives of Bt strain HD1 subspkurstaki have been widely used to control the forest pests such as the gypsy moth (Lymantria dispar), spruce budworm (Choristoneura fumiferana), the pine processionary moth (Thaumetopoea pityocampa), the European pine shoot moth (Rhyacionia buoliana) and the nun moth (Lymantria monacha). Some progresses of transferring and expressing Bt toxin gene in forest trees are offered with a discussion on the limits and future prospects of using Bt products in forestry. Biography: Li Gui-ming (1967-), male, engineer in Pingshan Forestry Chemicals Insecticides Factory, Harbin 150324, P. R. China Responsible editor: Chai Ruihai     

Diurnal change of gas exchange ofRhodiola sachalinensis transplanted from different habitats in Changbai Mountain

Rhodiola sachalinensis growing in the different habitats, such as Xiaotianchi plot (altitude 1800 m), Tree line plot (altitude 2000 m) and Tianwenfeng plot (altitude 2325 m) of Changbai Mountain (northern slop) were transplanted to Harbin Experimental Farm for determining its gas exchange. The study results indicated that the diurnal changes of gas exchange ofRh. sachalinensis transplanted from different habitats were still different though the morphological appearance of the newly sprouted above-ground part had become more similar. For net photosynthesis rate (Pn), stomatal conductance (Gs) and apparent quantum yield (AQY), the diumal change curves ofRh. sachalinensis transplanted from the three plots were similar, but the data value were different. For the dark respiration rate (Rd), transpiration rate (Tr) and water use efficiency (WUE), diurnal change curves of the three plots were obviously different. This study is supported by Natural Science Foundation of Heilongjiang Province. Yan Xiufeng, male, born in March 1965, associate professor, Open Research Laboratory of Forest Plant Ecology, Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Zhu Hong     

Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence

Female inflorescence of Betula platyphylla was sampled at an interval of each two days to analyze the background of gene expression in floral phase. On the basis of SMART strategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA was from that of the others by RT-PCR which were subsequently used to construct a subtracted cDNA library. The result of the ESTs (expression sequence tags) blastX showed that the genes in the subtracted cDNA library could be mainly clustered into 5 groups related to metabolism, transportation and signal transduction, cell cycle, stress response, and regulation. The relationship between gene expression and development was also discussed.     

Nitrate reductase activity and its diurnal variation rhythm for Camptotheca acuminata seedlings

Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of different positions was observed,and the correlations between leaf NRA, leaf area and lamina mass per unit area (LMA) were also examined. The results showed that NRA in the leaf was significantly highest, compared with that in other organs such as roots, stems and leaves. In this experiment, the 10 leaves were selected from the apex to the base of the seedlings in order. The different NRA occurred obviously in leaves of different positions of C. acuminata seedlings from the apex to the base, and NRA was higher in the 4th-6th leaves.The diurnal change rhythm of leaf NRA showed a one peak curve, and maximum NRA value appeared at about midday (at 12:30 or so). No obvious correlations between NRA and leaf area or lamina mass per unit area were observed. This study offered scientific foundation for the further research on nitrogen metabolism of C. acuminata.     

Study on tracheid variation ofPicea koraiensis (nakai) in natural stand and plantation

Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thickness of tracheid wall were significant differences between the growth rings. All those characteristics tend to increase from heart-center to bark. In natural stand, it has positive correlation between the characteristics. In plantation, the tracheid length has positive correlation with the trachied diameter, while both the trachied length and the trachied diameter has negative correlation with the thickness of trachied wall. The tracheid length and diameter have no significant difference in growth between natural stand and plantations. The thickness of tracheid wall from the plantation is a little thicker than that from the natural stand before 15 years. Foundation item: This paper was part of State 9th Five-Year Plan project of “Early Mensuration ofPicea koraiensis (nakai)”. Biography: REN Xu-qin (1973-), female, graduate student in Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Song Funan     

Relationship between trophic component of different poplar strains and occurrence ofSaperda poplnea

An experimental area of poplar was established in Songyuan of Jilin Province in 1999 for testing the resistance of different poplar stains toSaperda poplnea. Incidence ofS. poplnea on ten poplar strains were investigated, and the main trophic component of branches of these poplar trees were measured and analyzed in April 2001. The results showed that there existed significant difference in population size ofS. poplnea on different poplar strains, and the branches of these poplar strains have significant difference in nutrient component and content of amino acids. The population size of this pest had a significantly positive correlation with dissolvable total sugar and water content but had no significant correlation with content of total nitrogen and protein nitrogen. Foundation Item: This paper is part of the subject of integrated control of longicorn of poplar for mainly focusing on pest resistance, which was supported by Jilin Provincial Forestry Department (96-010). Biography: Gao Chang-qi (1949-), Research Fellow, Doctorate Tutor, Jilin Provincial Academy of Forestry Science, Changehun 139931, P. R. China. Responsible editor: Chai Ruihai     

New cell line establishment of a cell line from embryos ofDendrolimus superans

A new cell line was established from 5-day-old embryonated eggs ofDendrolimus superans and has been designated NEAU-Ds-950821. The cell line consists of mixture of cell types, including majority of spherical shaped cells and a few of spindle shaped cells. The cell line has a population of doubling time of 52.6 h. Chromosome analysis revealed typical lepidopteran chromosomes. Isozyme characterization of Esterase showed the patterns were different from other three cell lines (Ms-927311, Xc-920730, and SF-21AE). Virus infectivity tests revealed the cell line can supportD. superans cytoplasmic polyhedrosis virus. The project is supported by National Science Foundation of China Responsible editor: Chai Ruihai     

Adaptive responses of<Emphasis Type="Italic">Acer ginnala,Pyrus ussuriensis and Prunus davidiana</Emphasis> seedlings to soil moisture stress

One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moisture contents (75.0%,61.1%, 46.4% and 35.4%). The results showed that net photosynthesis rate (NPR), transpiration rate (TR) and stomatal conductance (Sc) of seedlings of the three species decreased with the decease of soil moisture content, and Amur maple seedlings had the greatest change in those physiological indices, followed by Ussurian pear, David peach. Amur maple and Ussurian pear seedlings also presented a decrease tendency in water use efficiency (WUE) under lower soil moisture content, whereas this was reversed for David peach. Under water stress the biomass allocation to seedling root had a significant increase for all the experimental species. As to root/shoot ratio, Amur maple seedlings had the biggest increase, while David peach had the smaliest increase. The leaf plasticity of Amur maple seedlings was greater, the leaf size and total leaf area decreased significantly as the stress was intensified. No significant change of leaf size and total leaf area was found in seedlings of Ussurian pear and David peach. It was concluded that Amur maple was more tolerant to soil moisture stress in comparison with David peach and Ussurian pear.     

The influencen of stand state on the occurrence ofDendrolimus superans (Butler) in Daxing’an Mountains

Dendrolimus superans (Butler) occurred in the vast areas of Daxing’an Mountains forest, in Heilongjiang Province, in 1990. Stands damaged byI). Superans seriously, intermediately and lightly show patch shape distribution within damaged area. By ordination analysis and correlation analysis between ordination factors and coordinate axis. It was found that occurrence ofD Superans in different extent is owing to the effect of forest age, composition and exposure. The tended young pure forests grown on the sunward slopes are most seriously damaged and non-tended middle-age mixing stands grown on the sunless slopes are most lightly damaged. Therefore, in order to preventD. superans from seriously damaging larch forests, relatively large crown density (P > 0. 7) should be kept, and broadleaf trees should be also properly preserved. This research project was supported by Scientific and Techndogical Committee of Heilongjiang Province