滇西保山地区的假松茸产量与生境关系研究

确定了云南省保山地区松茸的分类地位,系与松茸同属不同种的Ｔｒｉｃｈｏｌｏｍａｂａｋａ－ｍａｔ－ｓｕｔａｋｅ,俗称假松茸或青冈松茸;研究了它的周年发生规律及产量分布状况。７月中旬为松茸始发期,８月下旬为子实体发生的高峰,１０月下旬基本结束;以８月上旬至９月上旬为主产期,其产量占全年产量的６９．９％。此外还探讨了假松茸发生的生态条件,以及松茸可持续发展研究的初步结果。     

榆举肢透翅蛾的研究

榆举肢透翅蛾是导致榆树间接死亡的钻蛀性害早。在兰州地区两年发生一代，以幼虫在虫道越冬，老熟幼虫在丝质茧内化蛹，５月中，下旬－７月焉旬或８月上旬为蛹发生期，６月中旬－８月中，下旬为成虫发生期，６月下旬－８月下旬为卵发生期，７月上旬始见初孵幼虫，１０月上旬幼虫越冬。     

光肩星天牛生物学特性及预测预报的研究初探

该文研究了光肩星天牛的生物学特性,在呼市地区二年发生一工,以老熟幼虫,初龄幼虫及未孵化的幼虫在孵壳内均可越冬,也有极少数的以蛹越冬。成虫６月下旬始见,７月中旬进入高峰期,８月中旬进入盛末期。雌虫平均产卵量为２２粒。孵始见期为７月上旬,始盛期为８月上旬,高峰期为８月下旬,盛末期为９月上旬。该文提出的发生期,发生量的预测预报方法具有实用价值。     

竹小蜂防治技术

一、生活习性 竹小峰属膜翅目，广肩小蜂科，主要为害毛竹、箬竹，幼虫取食小枝管壁，刺激小枝管壁膨大成瘿。竹林为害后，营养不良，长势减弱，发笋减少，立竹头重脚轻，以致衰败枯死。 竹小蜂１年１代，蛹在虫瘿中越冬，次年３月开始羽化。３月下旬至４月上旬产卵，卵期８－１０天，幼虫期４－５月，８月下旬９月上旬幼虫化蛹越冬。 二、试验方法 我们于５月上旬在祁阳县阳明山林场进行试验，采用钉子或铁钻在毛竹莞部离地６－９厘米的背风面打一孔，用注射器将４０％的氧化乐果原液按每株２毫升注射，利用竹液向上运输将药液送到竹枝节，…     

不同采种期金钱松种子品质的研究

对１９９７ 年８ 月至１１ 月期间,９ 次在南京林业大学树木园所采金钱松种子的质量进行了研究．结果表明：１０ 月下旬以后采集的种子出籽率、发芽率和活力最高．１０ 月下旬至１１ 月上旬为金钱松种子最适宜的采种期     

竹箩舟蛾的研究

竹箩舟蛾是竹子的重要食叶害虫,分布于我国南方产竹各省,在浙江省１ａ３～４代,均以蛹于土表下越冬。成虫发生期分别为４月上旬～５月上旬、６月上旬～７月上旬、７月下旬～８月下旬、９月下旬～１０月中旬。幼虫危害期分别为４月下旬～６月中旬、６月中旬～８月上旬、８月中旬～１０月上旬,以第３代蛹越冬者幼虫可延至１０月下旬,第４代为１０月中旬、１１月下旬。第３代幼虫各龄食叶量分别为１．５７、７．７３、１６．３６、５７．０２、５７９．７８ｃｍ＾２,幼虫期共取食竹叶６６２．４６ｃｍ＾２。雌性幼虫期食叶量比雄性多１２％～１５％,每头成虫产卵量为１６１～２８６粒。天敌有赤眼蜂、黑卵峰、姬蜂、寄蝇等。并提出了相应的防治方法。     

华竹毒蛾生物学特性及防治方法的初步研究

华竹毒蛾是毛竹的食叶害虫，在安福武功山区一年发生３代，以蛹在竹杆上的地面灌木杂草叶背越冬，翌年４月中旬开始羽化产卵。１、２、３代幼虫发生危害期分别为：４月下旬－６月下旬，７月上旬－８月上旬，８月中旬－１０月中旬。以第２代发生整齐且危害最烈。在幼虫１－３龄期用ＤＤＶＰ插和烟雾剂进行熏杀，效果可达８０％，蛹期寄生虫较多，可利用于防治。     

榆斑蛾的研究

榆斑蛾系单食性害虫。幼虫暴食榆树叶片，在兰州曾一度成灾。作者对其虫态特征、生物学特性和药剂防治进行了系统研究。该虫在兰州地区一年只发生一代。各虫态的发生期：成虫５月下旬、６月上旬至７月下旬；卵６月上、中旬至７月下旬，８月上旬；幼虫６月中、下旬至１０月上、中旬；蛹８月上、中旬至次年７月上旬。幼虫共分８龄，为害盛期为７月中、下旬至８月中旬，以茧蛹越冬。经数种药剂进行杀卵、杀幼虫、杀成虫的试验、示范，以１：１０００倍的２．５％澳氰菊酯乳剂或４０％水胺硫磷乳剂进行防治，均可取得满意的防治效果。     

昆明地区华山松球蚜发生规律研究

１９８９年３月－１９９２年８月在嵩明县大哨及白邑两乡的５－７年生华山松幼林内设立标准地１０块,结合室内饲养,观察华山松球好的发生规律及各环境因子对其种群消长的影响。结果是：华山松球蚜在昆明地区１年发生８代;２月上旬当日均温达到８℃左右时越冬雌成虫开始产卵繁殖;１１月,当日均温降至５℃以下时雌应停止产卵;雌成虫分别于３月中旬、５月下旬、１０月中旬出现３次产卵高峰;降雨强度、天敌是影响林间球蚜种群的重要因子,其次是华山松的营养状况、温度。其化学防治时间以 ４月中旬－ ５月上旬以及 １０－ １１月最好, ５－ ６月以天敌控制。     

萧氏松茎象生物学特性及其防治研究

萧氏松茎象是严重蛀食国外松主干基部皮层的新害虫。该在江西吉安等地两年发生一代,以幼虫和成虫越冬。越冬成虫３月中下旬出忌化孔活动,４月下旬开始产卵,５月中旬开始孵化为幼虫,当年１２月上旬幼虫越冬,至翌年３月中旬越冬幼虫复苏,８月中旬开始化蛹,９月中旬开始羽经为成虫并在蛹室内越冬。     

Improving the evaluation of multiple-dowel-type connection strength

Our study focuses on predicting the ultimate short-term load carrying capacity of timber-to-timber connections with dowel-type fasteners. The wide range of possible configurations in practice makes the resolution of these values by tests unrealistic. Moreover, different current regulations do not consider some specific failure mechanisms. In many countries, the reduction of resistance involved by this phenomenon is taken into account by considering an effective number of dowels (n_ef) smaller than the actual number of dowels (n) in the connection. However, these different regulations disagree on the values of n_ef and on other points (spacing, partial coefficient of security, formulas). These discrepancies in design rules invite the fundamental research on this topic and, therefore, new methods are sought in order to estimate the load carrying capacities of the connections. In the light of these, our approach consists of predicting the load carrying capacity with the neural network numerical tool. The results obtained by this analysis tool are satisfactory, although the model remains complex. Subsequently, we focus on the simplification of this numerical model with classical regression techniques in order to implement it in a design code.     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

Parasitic Ichneumonoidea on the horse chestnut leaf miner, Cameraria ohridella (Lepidoptera: Gracillariidae) in Slovakia

Parasitic Hymenoptera from the suprafamily Ichneumonoidea attacking the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) were studied in southwest Slovakia during 2000 and 2001. The search for such species resulted in the determination of eight ichneumonid species, Gelis agilis (Fabricius), Itoplectis alternans (Gravenhorst), I. clavicornis (Thompson), I. maculator (Fabricius), Scambus annulatus (Kiss), S. brevicornis (Gravenhorst), Zatypota percontatoria (Müller), Adelognathus sp. and a braconid Colastes braconius Haliday. The most abundant species was S. annulatus. All these species recorded are polyphagous and often facultative hyperparasitoids, except C. braconius, which departs from this norm in not being hyperparasitic. The presence of more diversified native parasitoids and hyperparasitoids from the Ichneumonoidea predicate a slow successive adaptation of the parasitoid fauna to the invasive host, Cameraria ohridella.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.     

Populations of adult fungus gnats and shore flies in British Columbia container nurseries as related to nursery environment,and incidence of fungi on the insects

Adult fungus gnat and shore fly populations were monitored in four container nurseries near Victoria, British Columbia. In general, populations of both insects were larger in summer than in winter. Also, both insects were more abundant in the nursery with a plastic-covered, soil floor, which favored moisture accumulation and build up of algae, liverworts and mosses, than in nurseries with other types of floors such as cement. Results of fungus isolations revealed that gnats and flies both harbor the seedling pathogens Botrytis cinerea and species of Fusarium and Phoma, plus several non-pathogenic fungi. The results are discussed in relation to nursery sanitation practices, their effects on gnat and fly populations, and some possible roles of these insects in seedling disease epidemiology.     

Insecticidal activity of certain medicinal plants

The methanol extracts of eight species of medicinal plants were tested for insecticidal activity in third instar larvae of Egyptian cottonworm (Spodoptera littoralis). All extracts showed a certain degree of larval toxicity. The extracts of Ocimum basilicum, Origanum majorana and Salvia officinalis appeared to be highly toxic. The extracts significantly affected the growth indexes [relative growth rate (RGR), efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD)].     

A new norlignan from Taxodium ascendens

A new norlignan, (2R,3R,4S,5S)-2,4-bis(4-hydroxyphenyl)-3,5-dihydroxy-tetrahydropyran (1), together with 9 known compounds were isolated from the branches and leaves of Taxodium ascendens. Their structures were mainly determined on the basis of MS, IR, 1D and 2D NMR spectral evidences. Methanol extract showed inhibitory activity on carbonic anhydrase II with an IC₅₀ value of 4.27 µg/ml, acetone extract and methanol extract inhibited activity of cathepsin B with IC₅₀ values of 2.12 and 3.71 µg/ml, respectively.     

Pinus contorta growth in northern Sweden as affected by soil scarification

The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m³ ha^–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m³ ha^–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future.