松尺蠖生物学特性与防治方法

松尺蠖(B up a lus p in ip aria L innaeus)是鳞翅目、尺蛾科的一种危害云南松、华山松针叶的害虫。在盐源县一年发生1代,以幼虫在树干周围土壤中越冬。翌年2月上旬开始活动,3月中旬至5月下旬幼虫取食危害盛期,6月下旬幼虫下地化蛹,8月中旬为成虫羽化始期,8月下旬至9月中旬为羽化盛期,9月下旬至10月上旬成虫羽化产卵结束,产后三周左右卵孵化出幼虫,9月下旬到翌年2月中旬为幼虫越冬期。其防治措施为卫生抚育、物理防治、化学药剂防治、生物防治和灯光诱杀防治。     

栗实象甲生物学特性及综合防治技术研究

栗实象甲(Curculio davidiFairmaire)是板栗的重要果实害虫,通过对该虫生物学特性及综合防治技术研究表明,该虫在秦岭山区镇安县2年发生1代,以老熟幼虫在土内越冬,第2年在土里渡过,直到第3年6月中旬陆续化蛹,7月上旬开始出现成虫,7月下旬至8月上旬为成虫羽化盛期,8月下旬至9月下旬为产卵期,9月上旬幼虫开始孵化,9月间为蛀果期,10月上旬老熟幼虫咬破栗壳脱果,入土越终。采用林业防治、人工防治和化学药剂防治等综合技术取得了较好防治效果。     

侧柏生态防护林双条杉天牛生物学特性观察及防治对策研究

双条杉天牛在滕州主要1a发生1代(占75%),少数2a发生1代(占25%)。以当年羽化的成虫在树干木质部边材的蛹室内越冬(两年发生一代的以当年幼虫在木质部虫道内越冬),翌年2月中旬气温达10℃以上时成虫开始在树皮上咬一扁圆形孔钻出;3月中旬至4月上旬为出孔盛期;3月下旬为产卵盛期,卵历期14～18d;4月上旬为孵化盛期。5月上旬幼虫开始蛀入木质部内,1a发生1代的幼虫历期150d左右,2a1代的幼虫历期510d。9月上旬为化蛹盛期,蛹历期18～20d。9月下旬为羽化盛期。采取生物、化学、物理、营林等综合防治技术,有效地控制该虫的危害,达到长期有虫不成灾,实现森林健康。     

通辽地区杨干象发生规律试验观察初报

通过选取样株和定期定点观察,对通辽地区杨干象发生规律进行了调查研究,结果表明:杨干象在内蒙古通辽市1 a发生一代,以幼虫(大多数)或卵(少数)在寄主枝干韧皮部越冬。4月下旬至5月上旬,越冬的幼虫开始活动,越冬的卵也开始孵化。5月下旬至6月上旬,幼虫蛀入木质部化蛹,蛹期12 d左右,6月下旬逐渐开始羽化,7月中旬为羽化盛期。7月下旬至8月上旬交尾产卵,不同时间产的卵的卵期差异很大,8月中旬产下的卵,卵期平均12 d; 9月上旬产的卵,卵期平均20 d;后期产下的卵直到第二年春季才孵化。     

延边地区舞毒蛾生活史和幼虫发生期预测模型研究

通过野外调查的方法,对吉林省延边地区舞毒蛾的生活史及幼虫孵化率进行了研究。结果表明,舞毒蛾在延边地区1年发生1代,以完成胚胎发育的"卵内幼虫"越冬。翌年5月上旬;杨树将要萌芽时幼虫开始孵化出壳。幼虫孵化始盛期为5月中旬,高峰期为5月下旬,末期为6月上旬;幼虫在7月上旬开始老熟化蛹,化蛹始盛期为7月中旬,高峰期为7月下旬,末期为8月上旬;成虫在7月中旬开始羽化,羽化始盛期为7月下旬,高峰期为8月中下旬,末期为8月底至9月初;产卵始盛期在7月中旬,高峰期为8月中下旬,末期在8月底至9月初;卵在8月底开始发育成较为完全的幼虫胚胎,随之进入滞育状态。根据舞毒蛾幼虫孵化率与日均温值的相关性,建立线性回归模型Y_1=12.074 2X_1-139.190 8来测报舞毒蛾幼虫的当日孵化率,并进行了回测验证。     

甘肃线小卷蛾生物学特性

甘肃线小卷蛾主要以幼虫危害油松当年新芽，在甘肃兴隆山国家级自然保护区人工油松林内普遍发生，被害林木顶梢枯黄呈火烧状。此虫1a发生1代，以卵在当年生针叶上越冬；翌年5月中旬开始孵化，5月中、下旬为孵化盛期；幼虫4龄，5月中旬到7月中旬幼虫危害新芽，蛹期7月上旬到8月中旬；8月上旬开始羽化，中旬为羽化盛期；8月中、下旬为产卵盛期，9月上、中旬进入越冬状态。6月中旬，用2．5％敌杀死乳油5000倍液喷雾，防治效果在95％以上，用40％亚胺硫磷乳油1000倍液喷雾，防治效果90％左右；羽化期可利用黑光灯诱杀成虫。     

喜树暗斑螟生物学特性及防治

喜树暗斑螟Euzophera sp．是国内危害喜树Camptotheca acuminma Decn．的新害虫，在江西安福1a发生4代，以蛹在寄主树皮缝和枯卷叶内越冬。越冬代翌年4月上旬开始羽化并产卵。各代幼虫发生期依次为：4月中旬至6月中旬、5月下旬至7月下旬、7月上旬至9月上旬、8月中旬至10月中旬。在幼虫始盛期用40％氧化乐果乳油与水1：1的混合液涂环1周(宽为直径的1／3)，对当代防治效果达90％以上。     

槐尺蛾生物学特性及其防治技术

槐尺蛾在石家庄 1a 3代 ,幼虫危害盛期为 5月下旬、7月中旬和 8月下旬 ;幼虫分散危害 ,有吐丝悬垂习性。化蛹期为 5月下旬至 6月上旬、7月中旬及 8月下旬至 9月上旬 ;幼虫入土化蛹越冬。幼虫幼龄期可采用 2 .5 %溴氰菊酯乳油 2 0 0 0倍液 ,4 0 %氧化乐果乳油 80 0倍液 ,90 %晶体敌百虫 10 0 0倍液防治 ,死亡率均可达 95 %以上。     

小云斑鳃金龟生物学特性研究

小云斑鳃金龟在白龙江林区4年1代，以幼虫在土壤中越冬。越冬幼虫于每年4月上旬上升为害，至10月下旬下迁越冬，活动范围为10～25cm，越冬深度以40～70cm居多。成虫始发期为6月中旬，盛期为7月中、下旬；田间幼虫孵化盛期为8月上、中旬。各虫态的历期：蛹期29d，卵期26d，1龄幼虫340d，2龄幼虫365d，3龄幼虫700d，成虫16d。成虫雌雄性比1．2：1，昼伏夜出，21：00～23：00为出土活动高峰，雄虫有极强的趋光性，雌虫的趋光性极弱。成虫不取食，雌虫产卵为单粒散产，产卵量平均为26粒，多产于15cm耕作层的卵室中。土层深厚、富含有机质及含水量适宜的地块虫害发生较重。     

沈阳地区美国白蛾发生世代及规律的研究

2012年～2014年在沈阳地区进行美国白蛾发生规律研究的结果表明，美国白蛾在沈阳1年发生2代，第1代幼虫期为5月下旬至7月中旬，第2代成虫期为7月中旬至8月中旬，卵期7月下旬至8月中旬，幼虫期8月上旬至9月下旬，蛹期9月中旬至次年4月下旬至5月上旬。美国白蛾虫态有重叠现象，1～2代历期不等，第2代成虫产卵期较之第1代明显变短，而幼虫期和蛹期又明显较之第1代变长。     

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.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

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.     

Biogeochemical impacts of clearfelling and reforestation on blanket-peatland streams: II. major ions and dissolved organic carbon

Streams and drains in blanket-peatland forest in western Ireland were sampled weekly over 5 years, 1996–2000, using continuous, depth-proportional passive sampling. Analysis was for pH, alkalinity by Gran titration, anions by IC, metals by ICP, aluminium speciation by loaded-resin exchange, and dissolved organic carbon (DOC) by absorbance at 320 nm.

Effects of felling are identified graphically from two forest drains whose catchments (both about 1 ha) were clearfelled, and partial clearfelling of one larger catchment (somewhat over 1 km²), in summer 1999. Calcium concentrations and alkalinity were increased in the drain- and streamwater from the felled areas. The pH was increased in drains, while in the larger stream, pH range decreased while the mean increased. Phosphorus increased markedly with clearfell, in the absence of recent fertilising, and also increased with fertilising; these results are reported in an accompanying paper. Ammonium-nitrogen concentrations were increased in the two drains with felling, and temporarily decreased in the larger stream. Nitrate increased in some cases. Potassium and manganese concentrations also increased. Concentrations of DOC and organic monomeric aluminium increased gradually, subject to a continuing strong annual cycle. There were no clearfelling effects on concentrations of solphate, suspended solids or inorganic monomeric aluminium. In the two drains (fully clearfelled), concentrations of sodium, chloride and magnesium, and conductivity, were all reduced after felling. Fertilising effects other than for phosphorus were indistinct.

Effects of the combined clearfell–reforestation treatment were testable statistically, using randomised intervention analysis, between two larger streams (1 km²) as a treatment–control comparison. There were statistically significant positive responses in streamwater concentrations of nitrate, potassium, calcium, DOC and aluminium fractions. The implications for management practice depend on whether the loss of nutrients is sustainable for future crop productivity, and whether critical limits and loads of receiving ecosystems are exceeded.     

Effect of Drought on Growth and Mortality of Actively Growing Norway Spruce Container Seedlings Planted in Summer

Survival, root egress and height growth of 13-month-old actively growing Norway spruce ( Picea abies (L.) Karst.) container seedlings exposed to preplanting drying treatments (0, 4, and 8 days) and postplanting drought periods (1, 2, 3, and 4 weeks) were studied in the field between 5 July and 18 August 1999. The mortality of seedlings increased and the height growth and root egress decreased throughout the postplanting drought period. Postplanting performance was also affected by preplanting drying treatments. The results indicate that no risk of excessive mortality and growth restrictions occurs when actively growing seedlings are planted in summer, provided that seedlings are well watered before planting and the drought period does not exceed 3 weeks.     

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.     

qPCR quantification of Ophiognomonia clavigignenti‐juglandacearum from infected butternut trees under different release treatments

The use of a molecular assay for quantifying conidia of Ophiognomonia clavigignenti‐juglandacearum, the fungal pathogen responsible of butternut canker, was investigated. Purified DNA from conidia collected on glass fibre filters of a passive rain collectors was quantified using a TaqMan real‐time quantitative polymerase chain reaction (qPCR) assay. The qPCR assay could specifically discriminate the target species from all other North American known species of Ophiognomonia, and it was sensitive enough to repeatedly detect one conidium. A linear relationship between numbers of conidia and qPCR C_t values was determined, and used to assess the sporulation of the pathogen under trees that were released to promote their vigour. In total, 977 samples of field‐captured conidia from 49 trees, at two locations, and from two successive growing seasons were analysed. No significant difference of sporulation was observed under control and release treatments. However, our results demonstrated that qPCR assay was reliable for detecting and quantifying O. clavigignenti‐juglandacearum from environmental samples, which will be useful to assess further control methods for this disease.     

The potential of alley cropping in improvement of cultivation systems in the high rainfall areas of Zambia I. Chitemene and Fundikila

Three trials investigating the potential of alley cropping to improve the traditional systems of cultivation, chitemene and fundikila, in the Northern Province of Zambia are described. Flemingia congesta, Tephrosia vogelii, and Sesbania sesban, were grown in association with finger millet, groundnut, cowpea, and maize in various traditional cropping sequences. The indigenous species Tephrosia vogelii and Sesbania sesban were not able to withstand repeated pruning and the long following dry season, and were replaced with Calliandra calothyrsus, and Cassia spectabilis.Over a four year period, there was no benefit by alley cropping with any of the tree species on crop yields, and yields in alley crop treatments even dropped significantly below the control treatments in the fourth year, casting doubt on the potential of alley cropping for sustainable production. There was also no consistent effect on soil chemical characteristics in any of the trials. It was suggested that this lack of beneficial response to alley cropping was due to low tree biomass production low quality of prunings, and an inappropriate cropping sequence. There was no evidence that alley cropping contributed to enhanced nutrient recycling, despite substantial localised pools of soil nutrients, particularly in the chitemene, with which recycling could potentially occur.     

Toxicity of biocide GCSC-BtA on arthropod pests under different temperature conditions

The present research dealt with the toxicity of GCSC-BtA (Germany–China Scientific Cooperation-Bacillus thuringiensis-Abamectin), a new type biocide developed by conjugating a toxin from Bacillus thuringiensis (B.t.) with Abamectin from Streptomyces avermitilis, on arthropod pests under different temperature conditions. The results showed that GCSC-BtA possessed higher toxicity than B.t. crystal, Abamectin or Cypermethrin, with pest mortalities of 97.9, 93.7, 96.4, 82.3 and 96.7% for Tetranychus cinnabarinus (Boisd.) (Acari, Tetranychidae), Frankliniella occidentalis Pergande (Thys., Thripidae), Aphis fabae Scopoli (Hom., Aphididae), Plutella xylostella (L.) (Lep., Plutellidae) and Cameraria ohridella Deschka et Dimić (Lep., Gracillariidae), respectively. Toxicities of GCSC-BtA to T. cinnabarinus and P. xylostella decreased significantly at the older developmental stage with an exception that egg stage had the highest tolerance, in which LC₅₀s of GCSC-BtA were 0.0001, 0.0019 and 0.0708 mg/ml for nymph, adult and egg of T. cinnabarinus, and that 0.0399, 0.2035 and 0.9033 mg/ml for the 2nd instar larvae, 4th instar larvae and egg of P. xylostella, respectively. Also, the biocide was more effective to the lower stage of A. fabae than the higher one with LC₅₀s of 0.0023, 0.0086 and 0.0171 mg/ml against 1st instar nymph, 3rd instar nymph and adult, respectively. In general, toxicity of the new type of biocide was positively related to temperature against all the tested pests, except against T. cinnabarinus, where it was almost similar at the three temperature conditions. GCSC-BtA displayed significantly lower toxicities at 15/20°C than 20/25°C or 25/30°C against F. occidentalis, A. fabae, P. xylostella and C. ohridella. However, no significant difference was found in the toxicities against F. occidentalis, A. fabae and C. ohridella above 20°C, whereas toxicity against P. xylostella increased as temperature raised. Therefore, to achieve higher efficacy in the field, application rate and time should be devised according to these factors.