Woody and herbaceous competition effects on the growth of naturally regenerated loblolly and shortleaf pines through 11 years

Four levels of vegetative competition were used to quantify the growth of loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.) in naturally regenerated, even-aged stands on the Upper Coastal Plain of southeastern Arkansas, USA. Treatments included: (1) no competition control, (2) woody competition control, (3) herbaceous competition control, and (4) total control of nonpine vegetation. After pines became established from natural seeding, herbicides were used to control herbaceous plants for 4 consecutive years and woody plants for 5 consecutive years. Even though 89% of crop pines on untreated check plots were free-to-grow 11 years after establishment, crop pines on vegetation control plots were larger (P<0.001) in mean dbh, total height, and volume per tree. From age 5 through 11 years, crop pine diameter growth increased on woody control plots and decreased on herbaceous control plots because of hardwood competition in the latter treatment. At age 11, crop pine volume production averaged 207 m³/ha on total control plots, 158 m³/ha on herbaceous control plots, 130 m³/ha on woody control plots, and 102 m³/ha on untreated check plots.     

Role of weeds in the management of nitrogen in a young Pinus radiata plantation

Pinus radiata trees were grown on a podzolized sandy soil at a second rotation site under the following treatments: total weed control, total weed control plus ammonium nitrate, strip weed control and no weed control. During the first two summers after planting the differences in needle water potential between trees under no, strip or total weed control were very small. Despite similar rates of net N-mineralization in strip and total weed control treatments, which averaged 64 kg ha^–1 yr^–1 in the 0–15 cm soil depth, weeds in the strip weed control treatment reduced soil mineral-N concentrations by 50–80%, leaching of N by the end of the first growing season by 45%, foliar-N concentrations by 4–14% and stem biomass at 20 months after planting by 46%. Although N-uptake by above-ground vegetation (trees plus weeds) was 49% higher in the strip weed control treatment, the amount of N apportioned to trees during the first 20 months after planting was reduced from 15.5 to 9.0 kg ha^–1. These effects of weeds were even more pronounced in the no weed control treatment. Since weeds had little effect on the needle water potential of trees and the annual rates of N-mineralization, but adversely affected N-uptake by trees, results indicate that weeds directly competed with trees for N, and thereby aggravated N-deficiency in trees. Application of ammonium nitrate after complete weed control increased foliar-N concentrations, and N-uptake and growth of trees, but also induced severe stem deformation.     

Effect of early age woody and herbaceous competition control on wood properties of loblolly pine

Early age competition control has been reported to significantly improve the growth and yield of plantation grown loblolly pine. The objective of this paper is to understand the changes in wood properties: basal area weighted whole disk SG, earlywood SG (EWSG), latewood SG (LWSG) and latewood percent (LWP) of 14 year-old trees which received early age herbaceous and hardwood competition control, using data collected from 13-sites across 4-physiographic regions in the southeastern USA. The study was laid out in a randomized complete block design and had four levels of weed control (no weed control; woody vegetation control; herbaceous vegetation control; and woody and herbaceous vegetation control), with four blocks at each site. Increment cores 12 mm in diameter were collected at breast height (1.37 m) from 9-trees in each plot and ring-by-ring SG, EWSG, LWSG and LWP measured using a X-ray densitometer. Whole disk basal area weighted SG and LWP were determined for each tree and used for analysis. A reduction in whole disk SG of 0.039 and 0.0014 and LWP of 7.38% and 3.62% was observed for trees which received total weed control compared to no weed control, for lower and upper Coastal Plain sites, respectively. For trees receiving total weed control compared to no weed control, it was observed that the diameter of the juvenile core increased by 20% on average across all physiographic regions. However, no change in the length of the juvenile period was observed among treatments other than the regional differences.     

落叶松红腹叶蜂的防治技术

本文描述了落叶松红腹叶蜂的管理和防治技术．管理技术包括：（１）提高测报水平；（２）制定和应用防治指标；（３）制定防治计划和开展防治措施。防治技术包括：（１）采取营林措施，使郁闭度保持０．７；（２）用壮苗造林，并适地适树；（３）利用天敌开展生物防治，还可以采用化学药物防治措施。     

落叶松人工林抚育间伐生态效益分析

通过对落叶松人工林实施强度(39.7%)、中度(32.8%)、弱度(21.6%)的抚育间伐试验,结果表明:抚育间伐能改变落叶松人工林的土壤理化性质,中度间伐区有机质、全N含量比对照提高107%和83%,有效N、速效P、速效K的含量均为间伐区大于对照区,土壤容重、持水量、孔隙度也为间伐区大于对照区;不同间伐区土层(5～20 cm)温度高于对照区1%～7%。光照强度以中度间伐为适度。降雨量为对照区>弱度区>中度区>强度区。蒸发量为强度区>中度区>弱度区>对照区。树冠截留量为对照区>弱度区>中度区>强度区。     

Herbicides are more cost-effective than alternative weed control methods for increasing early growth of Eucalyptus dunnii and Eucalyptus saligna

Effective weed control is an essential management task in establishing commercial tree plantations. Much of the current weed control strategies employed in Australian forestry relies on the use of available herbicides. However, given community concern regarding the use of herbicides, investigation of alternative weed control methods is warranted. We tested the ability and cost-effectiveness of mechanical (hand weeding and inter-row slashing), mulching (sawdust over newsprint, woodchips and jute), cover crops and herbicide applications for weed control in establishing eucalypt plantations. Jute matting and herbicide treatments reduced weed competition and increased seedling growth to age 2 years in plantations of Eucalyptus dunnii and Eucalyptus saligna in northern NSW, Australia. Growth increased by 269 % (Experiment 1) and 196 % (Experiment 2) in the Jute and by 216 % (Experiment 2) in the Herbicide treatments when compared to the control (no weed control) at 2 years age. As the Jute material deteriorated, after nearly 2 years, weed cover increased and there were significantly more weeds present in the Jute treatment compared to the Herbicide treatment. Jute matting costs approximately 15 times more than the herbicide regime used and, therefore, could not presently be considered a viable option for weed control in commercial eucalypt plantations. Other weed control treatments, including hand weeding, sawdust and woodchip mulches, slashing and sowing cover crops did not effectively control weeds and did not improve survival or increase seedling growth to age 2 relative to the control. We conclude that herbicides remain the most cost-effective weed control option available to commercial growers of eucalypt plantations.     

Selective herbicides for establishment of <Emphasis Type="Italic">Eucalyptus benthamii</Emphasis> plantations

Competition control is essential for successful eucalyptus plantation establishment, yet few selective herbicides have been identified. Five herbicides, flumioxazin, imazamox, imazapic, oxyfluorfen, and sulfometuron methyl, were evaluated at either pre- or post-weed emergence timing for selective weed control in the establishment of Eucalyptus benthamii, a frost-tolerant species showing promise for commercial plantations in the southeastern United States and southern Brazil. Herbicides were applied at two or three rates and compared to a non-treated control and to near-complete weed control obtained with repeated glyphosate directed sprays. Herbicides were most efficacious when applied prior to weed emergence, at 2 weeks after planting 16-week-old containerized eucalyptus seedlings. Pre-emergence imazapic treatments resulted in broad-spectrum and persistent weed control, with 77–82% bare-ground at 60 days after treatment, but both pre- and post-emergence applications of imazapic caused excessive eucalyptus injury at the highest rate tested. Imazapic, sulfometuron, and imazamox were most effective for grass control. Both timings of flumioxazin were effective for forb control at the early assessment. All pre-emergence treatments enhanced stem volume compared to the non-treated control, but post-emergence treatments did not, suggesting the need for early weed control to facilitate E. benthamii growth. Pre-emergence applications of medium and high sulfometuron, low imazapic, high imazamox, and high oxyfluorfen rates increased stem volume four-fold to six-fold compared to the non-treated control. Repeated glyphosate directed sprays increased stem volume nearly three-fold compared to the control. These results confirm one early report of flumioxazin effectiveness and identify imazamox and imazapic as new selective herbicides for eucalyptus culture.     

The effects of herbaceous and woody competition on planted white pine in a clearcut site

We investigated the effects of herbaceous and woody vegetation control on the survival and growth of planted eastern white pine (Pinus strobus L.) seedlings through six growing seasons. Herbaceous vegetation control involved the suppression of grasses, forbs, ferns, and low-shrubs, and was maintained for 0, 2, or 4 years after white pine seedlings were planted. Woody control involved the removal of all tall-shrub and deciduous trees, and was conducted at the time of planting, at the end of the second or fifth growing seasons, or not at all. Seedling height and basal diameter responded positively and proportionally to duration of herbaceous vegetation control. Gains associated with woody control were generally not significant unless some degree of herbaceous vegetation control was also conducted. Only herbaceous control increased pine crown closure and rate of crown closure. Herbaceous control and the presence of 5000–15,000 stems per ha of young overtopping aspen were associated with reduced weevil (Pissodes strobi Peck.) injury and increased pine height growth. The study suggests that white pine restoration strategies on clearcut sites should focus on the proactive, early management of understory vegetation and the gradual reduction of overtopping cover from woody vegetation to create a seedling light environment that supports acceptable growth with minimal weevil damage.     

潮间带消浪林海滨木槿光合作用的初步研究

以慈溪杭州湾滨海绿地试验林场的海滨木槿为对照,对比分析了杭州湾南岸潮间带消浪林海滨木槿的光合作用日变化、光合作用光响应曲线以及叶绿素含量特征。结果表明,消浪林海滨木槿净光合速率Pn日变化与对照相同,均呈双峰曲线,但其平均值显著下降,仅为对照的76.02%;光响应曲线经非直角双曲线拟合得到,潮间带海滨木槿最大净光合速率Amax为(22.36±3.22)μmol.m-2.s-1,是对照的91.75%,而光补偿点LCP为(28.57±1.51)μmol.m-2.s-1和暗呼吸速率Rd(1.98±0.31)μmol.m-2.s-1却是对照的1.44倍和1.33倍,表观量子效率AQ Y与对照相差不大;消浪林海滨木槿叶绿素a、叶绿素b和叶绿素总含量分别为(0.82±0.04)g.kg-1(、0.12±0.00)g.kg-1和(0.94±0.04)g.kg-1,分别是对照的65.08%、100.00%和68.12%。方差分析结果表明,消浪林海滨木槿的Pn、Amax、LCP、Rd、叶绿素a含量、叶绿素总含量与对照间存在显著差异,其他指标差异不显著。     

绿色威雷喷施松饵木防治松褐天牛试验

通过应用不同浓度的绿色威雷稀释液喷施松饵木进行松褐天牛林间防治试验,结果表明：1%、0.5%浓度的绿色威雷防治效果最好,株诱杀成虫分别达112.2头、112头,0.5%浓度防治成本相对较低,对下一代幼虫的控制效果达100%,处理的饵木不需进行清理就能对松褐天牛种群密度起到控制作用,在生产中应用以0.5%浓度为宜。     

永安市毛竹有害生物发生及防治对策

通过对永安市1987~2007年毛竹有害生物发生情况统计分析,结果表明:永安市毛竹有害生物种类多,危害大,发生面积呈上升的趋势。主要原因是竹林面积逐年扩大,生态环境遭受破坏,天敌减少,测报技术落后及防治方法不当等。在防治对策上应采取的措施是:科学经营管理毛竹,建立复杂稳定的生态系统;加大监测和预防工作力度;创新防治机制;积极开展毛竹防治项目工程治理;落实防治目标管理责任制,建立有害生物灾害应急管理机制,深入推广先进的测报防治技术。     

Integrierte Bekämpfung forstschädlicher Wühlmäuse

Mainly the following four species of voles (Arvicolidae) are harmful in forest plantations in Central Europe: the field vole (Microtus agrestis), the common vole (M. arvalis), the redbacked vole (Clethrionomys glareolus) and the water vole (Arvicola terrestris). Different possibilities of development of an integrated control programme are discussed. The most important factors are: identification and forecasting of damages, determination of control thresholds, optimized timing of control operation and selection of efficient control methods with minimized environmental hazards. Finally the system of surveillance of rodents in Bavarian forest plantations is described, whereby different preventive measures by means of forest cultivation play an important role. Furthermore new methods of forecast and of control such as bait station technique with new types of rodenticides and attractants are tested.     

云杉雪枯病的防治研究

云杉雪枯病的防治研究＠岳朝阳＠张新平＠刘振坤＠王波＠李新华＠黄新平￥新疆林业科学研究院￥新疆天山西部林业局￥新疆阿尔泰山林业局云杉雪枯病，防治试验，杀菌剂云杉雪枯病的防治研究＊岳朝阳张新平刘振坤王波李新华黄新平关键词云杉雪枯病防治试验杀菌剂云杉雪枯病（Ｌｏ...     

陕南松阿扁叶蜂发生规律及防治技术

在研究松阿扁叶蜂在丹凤的发生危害、生物学特性及发生规律的基础上,从不同防治方法、不同药剂中筛选出了该虫几种防治方法和防治有效药剂,采用树盘垦复,防效达85%;用40%氧化乐果乳油机动喷烟防治3龄前幼虫,防效达95%;用40%氧化乐果乳油1 000~1500倍液、2.5%敌杀死乳油2 000~3000倍液喷雾防治1~3龄幼虫防效均达93%;在郁闭度0.7以上的林分,用18 kg/hm2敌马烟剂、林丹烟剂防治1~3龄幼虫,防效达90%。     

Changes in soil carbon during the establishment of a hardwood plantation in subtropical Australia

Soil carbon (C) pools are not only important to governing soil properties and nutrient cycling in forest ecosystems, but also play a critical role in global C cycling. Mulch and weed control treatments may alter soil C pools by changing organic matter inputs to the forest ecosystem. We studied the 12-month mulch and weed control responses on the chemical composition of soil organic C and the seasonal dynamics of water extractable organic C (WEOC), hot water extractable organic C (HWEOC), chloroform-released organic C (CHCl₃-released C), and acid hydrolysed organic C (acid hydrolysable C) in a hardwood plantation of subtropical Australia. The results showed that compared with the non-mulch treatment, the mulch treatment significantly increased soil WEOC, HWEOC, and CHCl₃-released C over the four sampling months. The weed control treatment significantly reduced the amount of HWEOC and CHCl₃-released C compared with the no weed control treatment. Neither the mulch nor weed control treatment significantly affected soil acid hydrolysed organic C. There were no significant seasonal variations in soil WEOC, HWEOC, CHCl₃-released C, and acid hydrolysed organic C in the hardwood plantation. Solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy was used to study the structural chemistry of soil C pools in hydrofluoric acid (HF) treated soils collected 12 months after the mulch and weed control treatments were applied. Overall, O-alkyl C was the dominant C fraction, accounting for 33–43% of the total NMR signal intensity. The mulch treatment led to higher signal intensity in the alkyl C spectral region and A/O-A ratio (the ratio of alkyl C region intensity to O-alkyl C region intensity), but lower signal intensity in the aryl C and aromaticity. Compared with the no weed control treatment, the weed control treatment reduced signal intensity in the aryl C and aromaticity. Together, shifts in the amount and nature of soil C following the mulch and weed control treatments may be due to the changes in organic matter input and soil physical environment.     

荒漠化土地的发生及整治对策

通过对洮南市荒漠化土地发生原因的分析，提出了整治荒漠化的对策；调整产品结构，合理载畜量、乔、灌、草结合，合理开发资源；提高当地群众的认识程度，全民齐动手整治。     

Effective biological control of an invasive mealybug pest enhances root yield in cassava

Insects provide critical ecosystem services to humanity, including biological control of pests. Particularly for invasive pests, biological control constitutes an environmentally sound and cost-effective management option. Following its 2008 invasion of Southeast Asia, biological control was implemented against the cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) through the introduction and subsequent release of the host-specific parasitoid Anagyrus lopezi (Hymenoptera: Encyrtidae) in Thailand. In this study, we quantify yield benefits of mealybug biological control in Thailand’s cassava crop by using two different types of manipulative field trials: i.e., ‘physical exclusion’ cage trials and field-level ‘chemical exclusion’ assays. In cage trials with two popular cassava varieties, root yield and total dry matter (or ‘biological yield’) were a respective 4.0–4.2 times and 3.5–3.9 times higher in the presence of biological control. Extrapolating results from cage trials, biological control thus ensured an approximate yield gain of 5.3–10.0 T/ha for either variety. Under chemical exclusion trials, P. manihoti populations attained levels of 3266?±?1021 cumulative mealybug-days (CMD) over a 10-month time period, and no longer impact yields. Moreover, under effective P. manihoti control, both root yield and biological yield increased with season-long CMD measures, and pest management interventions-including insecticide sprays-led to notable reductions in yield. This study is the first to show how biological control effectively downgrades the globally invasive P. manihoti to non-economic status and restores yields in Thailand’s cassava crop. Our work emphasizes the economic value of biological control, reveals how current P. manihoti populations do not necessarily cause yield penalties, and underlines the central importance of nature-based approaches in intensifying global agricultural production.     

Erfolgreiche Bekämpfung der Orientalischen Schabe (Blatta orientalis) (L.) (Blattodea,Blattidae) and Hand eines Beispieles aus der Praxis

Zusammenfassung Die Orientalische Schabe (Blatta orientalis) wird in komplizierten Bekämpfungsterrains oft erfolglos bekämpft. Anhand eines Beispieles aus der Praxis werden Möglichkeiten aufgezeigt, wie man erfolgreich gegen die Orientalische Schabe vorgehen kann. Als entscheidender Gesichtspunkt wird die Aufspürung der Refugien angesehen. Die Orientalische Schabe zeigt eine hohe Affinität zu ihren Refugien. Die verschiedenen Bekämpfungsmethoden sollten sinnvoll kombiniert und aufeinander abgestimmt werden. Noch zu oft werden moderne Methoden der Schabenbekämpfung nicht angewendet und damit wichtige Einsatzmöglichkeiten vergeben. Die Ergebnisse der Arbeit vonFuchs, 1987) zum Verhalten vonBlatta orientalis sollten den Schädlingsbekämpfern auf Weiterbildungsveranstaltungen vermittelt werden.

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Successful control of the Oriental cockroach (Blatta orientalis) (L.) (Blattodea, Blattidae) demonstrated by way of an example of real control

Attempts to control the Oriental cockroach (Blatta orienitalis) have often failed in complex territories. An example of real control is presented to demonstrate how the Oriental cockroach can be satisfactorily controlled. Tracking down the refuges of the pests is considered the decisive approach to control. The Oriental cockroach shows a close affinity for its refuges. The various methods of control should be usefully combined and coordinated. It has been found that modern methods of cockroach control are not adopted in a great many cases and, therefore, potential fields of application are not adequately used. The results of the work ofFuchs (1987) investigating the behaviour ofBlatta orientalis should be conveyed to pest control experts in training courses.

     

不同杀虫剂防治国槐尺蠖药效试验

通过试验研究了使用50%灭幼脲Ⅲ号胶悬剂和25%溴氰菊酯乳油对国槐尺蠖的防治效果,结果表明:50%灭幼脲Ⅲ号胶悬剂1 500倍和25%溴氰菊酯乳油2 000倍液防治效果最好;国槐尺蠖在北京昌平地区每年发生4代,5月中旬为防治第1代幼虫的最佳时期,6月中旬为防治第2代幼虫最佳时期,第3代后世代交替,可根据虫情在2~3龄幼虫期喷药。     

The effect of weed control and fertilization on survival and growth of four pine species in the Virginia Piedmont

The growth response of loblolly pine (Pinus taeda L.), shortleaf pine (Pinus echinata Mill.), Virginia pine (Pinus virginiana Mill.), and white pine (Pinus strobus L.) to weed control and fertilization in the Piedmont of Virginia was assessed. Four different silvicultural treatments were evaluated: (1) check (no treatment); (2) weed control; (3) fertilization; (4) weed control plus fertilization. The weed control treatment included a series of herbicide and mechanical treatments to eliminate competing hardwoods. The fertilizer treatments added N, P, K, and S. Survival and growth was measured annually through age 5. There were significant differences in survival and growth among species. Survival was greatest for loblolly pine, lower in shortleaf and Virginia pine, and lowest in white pine. Fertilization without controlling the competing hardwoods decreased survival in all planted pines due to the increased hardwood competition. Loblolly pine was tallest through the 5-year period, shortleaf and Virginia pine were shorter and white pine was shortest. Silvicultural treatments had no impact on tree height but significantly affected DBH. Weed control increased DBH while fertilization did not. When applied in combination with weed control, there was no additional increase in growth of the pines due to fertilization beyond that from weed control only. Fertilization stimulated the growth of the competing hardwoods which were significantly taller in the fertilized plots.