Virulence and mycotoxic effects of Metarhizium anisopliae on Mahogany shoot borer, Hypsipyla robusta (Lepidoptera: Pyralidae)

Developing appropriate control measures for the Mahogany shoot borer,Hypsipyla robusta Moore has become increasingly important due to the severe damaging effect of the pest on the establishment of the saplings of Swietenia mahagoni Jacq(Sapindales:Meliaceae).Existing management methods are largely limited to silvicultural practices and spraying of chemical insecticides.To identify a potential fungal biocontrol agent,we compared the virulence of six native and two standard ARSEF isolates of Metarhizium anisopliae Metsch.against this pest.The average survival time and conidial yield of IWST-Ma7 was higher(6.2 to 7.3 days and 4.9 to 4.7 × 10 5 conidia/ml) than the standards.Significant difference in sporulation on the cadavers between isolates,doses and incubation periods were substantiated for the selection of potential strain.The mycotoxic effects of crude soluble protein extract when incorporated in the artificial diet,the ARSEF 2596 and ARSEF 3603 showed LD 50 value of 3.7% and 5.6%.However,IWST-Ma7 was highly lethal with significant lowest LD 50 value of 2.6%.The enzyme activity of IWST-Ma7 was highest for chitinase,CDA,protease and lipase viz.,1.90 U/mg,1.80 U/mg,0.98 U/mg and 0.80 U/mg respectively.However the enzyme activity of chitinase and Chitin deacetylase assay for all the isolates was significantly higher than protease and lipase activity.The ITS regions(5.8S rDNA and 28S rDNA) of seven isolates of M.anisopliae were amplified using the ITS1 and ITS4 primers which was a unique fragment of approximately 550 bp.Based on ITS regions,phylogenetic tree have been constructed and the isolates have been grouped in to 5 clades.The virulence and mycotoxic effects of different isolates could rationally be used to employ them for the management of the mahogany borer.     

Seed dispersal and its implications for silviculture of African mahogany (Entandrophragma spp.) in undisturbed forest in the Central African Republic

The study of seed dispersal has received considerable attention in tropical ecology with emphasis placed on its role in the maintenance of species diversity. Since seeds of numerous high-value tropical timber trees are nominally or actively wind dispersed, the subject is also of interest to tropical foresters. In central Africa, up to 70% of harvested timber trees are wind dispersed, including African mahoganies of the genus Entandrophragma. The dual goals of managing many remote areas in central Africa for both biodiversity and timber production values has led to the consideration of low impact logging techniques. In the Central African Republic, increasing light downwind of Entandrophragma has been proposed as a way of increasing regeneration and recruitment of these trees. Mean wind direction at the time of dehiscence of Entandrophragma angolense and Entandrophragma cylindricum was compared with compass orientation of seed shadows for five individuals in mature, undisturbed forest. Mean wind direction was found to be toward the northeast for morning, afternoon, and daily winds and was significantly different from the orientation of seed shadows for all trees. Mean branch direction did not vary significantly from a random pattern, but matched the direction of the seed shadow better than wind direction did. It is concluded that harvesting interventions aimed at increasing light downwind of Entandrophragma will not necessarily benefit seedlings of the species at the study site and further silvicultural research is needed to determine appropriate management interventions, particularly in remote areas of Africa where conservation values are important.     

Sustained mahogany (Swietenia macrophylla) plantation heartwood increment

In a search for an increment-based rotation for plantation mahogany (Swietenia macrophylla King), heartwood volume per tree was regressed on DBH (trunk diameter outside bark at 1.4 m above the ground) and merchantable height measurements. We updated a previous study [Wadsworth, F.H., González González, E., Figuera Colón, J.C., Lugo Pérez, J., 2003. Fifty-nine year performance of planted big-leaf mahogany (S. macrophylla King) in Puerto Rico. In: Lugo, A. Figueroa Colón, J.C., Alayón, M. (Eds.), Big-leaf Mahogany, Genetics, Ecology, and Management. Springer-Verlag, New York, pp. 343–357] and determined heartwood volume increment in a plantation between the 40th and 69th years. Although DBH growth rate declined with age, that for heartwood increased throughout the entire 69 years. This, with expected growing value per unit of heartwood volume with tree size, presents incentives for long rotations.     

Nepetalactone content in shoot cultures of three endemic Nepeta species and the evaluation of their antimicrobial activity

Rapid micropropagation of Nepeta rtanjensis, N. sibirica and N. nervosa was performed. Qualitative and quantitative nepetalactone content in methanol extracts of in vitro grown plants was analysed by reverse-phase HPLC coupled with UV and MS detection. Only trans,cis-nepetalactone was detected in shoots of N. rtanjensis, while cis,trans-nepetalactone stereoisomer was present in N. sibirica. No nepetalactone was observed in shoots of N. nervosa. The antimicrobial activity of methanol extracts, against eight bacterial and eight fungal species, was evaluated. All the tested extracts showed significant antibacterial and strong antifungal activity. However, N. rtanjensis extract exhibited the best antimicrobial potential.     

Silvicultural systems for plantation mahogany in Africa: Influences of canopy shade on tree growth and pest damage

Overexploitation of the African mahoganies, Khaya anthotheca and K. ivorensis, could lead to their commercial extinction in the near future. Efforts to establish plantations to sustain supply have been discouraged by the shoot borer Hypsipyla robusta Moore. We hypothesized that there is a shade level at which Hypsipyla attack and branching are reduced, but height growth is adequate. We report on the growth of these African mahoganies and Hypsipyla attack under three different forest canopy shade levels: open (55% open sky), medium shade (26% open), and deep shade (11% open). Hypsipyla attack on K. anthotheca was 85%, 11%, and 0% attack in the open, medium, and deep shade treatments, respectively. However, growth in medium and deep shade was slow. Mean tree height for K. anthotheca was 413.8, 126.2, and 54.5 cm in the open, medium and deep shade treatments, respectively. K. ivorensis showed similar trends. The reduced growth under these shade levels limit the use of this strategy for controlling Hypsipyla attack.     

Contribution of methylated exudate flavonoids to the anti-inflammatory activity of Grindelia robusta

The flavonoid pattern of an acetonic extract of Grindelia robusta Nutt. was investigated in detail. The flavonoids were enriched by CC. In addition to twelve known methylated exudate flavonols four compounds were identified for the first time in G. robusta. Several substances of the flavonoid complex, among them the main compounds quercetin-3-methylether and 6-OH-kaempferol-3,6-dimethylether, were tested for their activity to inhibit neutrophil elastase. Quercetin-3-methylether was shown to be most active with an IC₅₀ of 19 µM, thus obviously contributing to the anti-inflammatory activity of the drug.     

Early results from genetic trials on the growth of Spanish cedar and its susceptibility to the shoot borer moth in the Yucatan Peninsula,Mexico

Cedrela odorata (Spanish cedar) is a neotropical broadleaf tree species that is in high demand for furniture and interior fittings. In 1998, seed collections were made from Spanish cedar in the Yucatan Peninsula, Mexico, for genetic conservation and tree improvement projects. Progeny from these collections were established in genetic trials at Bacalar, Noh Bec, and Zoh Laguna in the Yucatan. Survival at 2 years was 73.5% at Bacalar, 72% at Noh Bec, but only 20% after 6 months for several replicates at Zoh Laguna. Mean 2-year height, number of years of Hypsipyla attack on apical shoots (over 2 or 3 years) and total branching over 2 years, were 1.3 m, 0.04 years, and 2.5 branches at Bacalar, and 1.9 m, 0.35 years, and 1.6 branches at Noh Bec. Selection of the three best provenances (Escárcega, Bacalar, and Calakmul) would result in an estimated cross-site gain of 8.6% in 2-year height. Within-provenance, cross-site heritabilities for 2-year height, shoot borer attack, and branching were 0.1 ± 0.02, 0.0 ± 0.02, and 0.0 ± 0.02, respectively. Single-site heritabilities for height at 2 years, shoot borer attack, and branching were 0.09 ± 0.05, 0.02 ± 0.04, and 0.09 ± 0.05 at Bacalar and 0.16 ± 0.07, 0.0 ± 0.06, and 0.0 ± 0.07 at Noh Bec. Given the known advantage of rapid growth to avoid Hypsipyla damage over the long term and the stable performance of provenances across sites for growth traits, we recommend provenance selection over multiple trials to reduce the risk of serious damage by the insect. Good provenances and other suitable seed sources, as well as proper site selection and silvicultural practices, are important tools for increasing yields from plantations of C. odorata.     

The impact of forest fertilization on growth of mature Norway spruce affected by Sirococcus shoot blight

The effects of forest fertilization and Sirococcus shoot blight on growth of mature Norway spruce (Picea abies (L.) Karst.) were studied in a field experiment. The single tree fertilization experiment was established with 144 sample trees in the year 2000. These trees were selected among the dominant and co-dominant trees of the stand in a way that half of the trees exhibited symptoms of Sirococcus shoot blight and the other half did not. One-third of the sample trees were fertilized with dolomitic lime, one-third with kieserite and gypsum and one-third were left unfertilized as control. The treatments were randomly assigned to the sample trees. As the experimental design became unbalanced due to tree mortality caused by bark beetle infestation final analyses were performed with the volume growth data of 125 sample trees only. An analysis of covariance was used to evaluate the effect of fertilization and Sirococcus shoot blight on volume growth. The average volume increment of the period 1977–1980 was used as a covariate attribute, assuming that during this period growth was not yet affected by Sirococcus shoot blight. Indeed an effect of Sirococcus shoot blight on growth turned out to start after 1980 and the analysis revealed that over the whole period 1981–2006 trees with shoot blight symptoms had a significantly lower increment. The increment reduction of the nonfertilized trees by Sirococcus   was 7.46±2.90$7.46\pm 2.90$% in 1981 and was continuously increasing with time to 37±3.78$37\pm 3.78$% by the year 2000. A significant positive effect of fertilization was only found for the kieserite+gypsum$\text{kieserite}+\text{gypsum}$ variant from 2002 to 2006, with the highest surplus increment in 2004 with 31.6±15.2$31.6\pm 15.2$%, calculated as average over the diseased and healthy group. However, a mitigation of the Sirococcus-caused increment loss via fertilization with kieserite and gypsum was statistically significant only for the year 2003. A moderate relationship between basal area increment and disease severity was found, indicating decreasing basal area increment with increasing disease severity.     

桉树蛀干新害虫--桉蝙蛾形态与生物学研究

桉蝙蛾是近年来在广西、广东新发现严重危害桉树的蛀干害虫,本文记述了该害虫的形态特征和生物学特性,该虫在广西分布于12个市49个县,10个自治区直属国有林场,232个乡镇,危害桉树面积达2 894.42 hm2,多数个体1年完成1代,以幼虫于12月中下旬开始在受害树干中越冬,次年2-3月化蛹,4月羽化,5月上旬初孵幼虫出现,6-8月幼虫上树转移危害,1年只有1次羽化;该虫主要分布在丘陵山地,以沟谷和坡底危害较严重,主要危害1～2年生巨尾桉和尾巨桉无性系.1年生和2年生受害桉树单株材积生长量下降率分别为16.70％和24.78％.沟谷和坡底1～2年生速生桉无性系是防治的主要对象.     

库尔勒香梨优斑螟触角感受器超微结构观察

为研究香梨优斑螟触角感器的种类、分布和形态特征,利用电子扫描显微镜,对香梨优斑螟成虫触角感器进行观察。结果表明:成虫触角上存在着6种化学感器,即毛形感器、刺形感器、柱形感器、耳形感器、腔锥形感器和鳞形感器,其中,毛形感器数目最多,柱形感器雄虫特有,柄节和梗节上没有发现感器。研究香梨优斑螟触角感器为其形态学、行为学和电生理学等方面的研究提供基础资料,同时对香梨优斑螟触角与其相近种昆虫触角间的差异及部分感器可能具有的生理功能进行了分析。     

Triterpenes and steroids from the leaves of Aglaia exima (Meliaceae)

A study on the leaves of Aglaia exima led to the isolation of one new and seven known compounds: six triterpenoids and two steroids. Their structures were elucidated and analyzed mainly by using spectroscopic methods; 1D and 2D NMR, mass spectrometry, UV spectrometry and X-ray. All the triterpenoids and steroids were measured in vitro for their cytotoxic activities against eight cancer cell lines; lung (A549), prostate (DU-145), skin (SK-MEL-5), pancreatic (BxPC-3), liver (Hep G2), colon (HT-29), breast (MCF-7) and (MDA-MB-231). The new cycloartane triterpenoid, 24(E)-cycloart-24-ene-26-ol-3-one 1, showed potent cytotoxic activity against colon (HT-29) cancer cell line (IC₅₀ 11.5 μM).     

Positive association between understory species richness and a dominant shrub species (Corylus avellana) in a boreonemoral spruce forest

Old growth stands of boreonemoral spruce (Picea abies) forests frequently have a shrub layer dominated by hazel (Corylus avellana) – a species which is generally excluded in intensively managed forests due to clearcutting activities. We sampled understory species composition, richness and biomass, as well as environmental variables beneath these two species and also within forest ‘gaps’ in order to determine the effect of overstory species on understory vegetation. Species richness and biomass of herbaceous plants was significantly greater under Corylus compared with plots under Picea and in forest gaps. Indicator species analysis found that many species were significantly associated with Corylus. We found 45% of the total species found under woody plants occurred exclusively under Corylus. Light availability in spring and summer was higher in gaps than under forest cover but no difference was found between plots under Corylus and Picea. Hence, reductions in light availability cannot explain the differences in species composition. However, Ellenberg indicator values showed that more light demanding species were found under Corylus compared to Picea, but most light demanding species were found in gaps. The litter layer under Picea was three times thicker than under Corylus and this may be an important mechanism determining differences in understory composition and richness between the woody species. The presence of Corylus is an important factor enhancing local diversity and small-scale species variation within coniferous stands. Hence, management should maintain areas of Corylus shrubs to maintain understory species diversity in boreal forests.     

Forest fragmentation and duration of forest tent caterpillar (Malacosoma disstria Hübner) outbreaks in northern hardwood forests

In northern forests dominated by aspen (Populus spp.), the duration of outbreaks of forest tent caterpillar (Malacosoma disstria Hübner) has been reported to increase with forest fragmentation. This relationship has not been tested in other forest types affected by this widespread native defoliator. From 2002 to 2007, a large-scale outbreak of this insect in the northeastern United States defoliated millions of hectares, with sugar maple (Acer saccharum Marsh.) the primary host. We used digital defoliation maps generated from aerial surveys and national land cover data to assess the effect of fragmentation on outbreak duration in areas of NY, MA, VT, and NH. We found that outbreak duration increased with forest cover and decreased with the forest edge, in opposition to the pattern previously reported for aspen-dominated forests in Canada. This pattern was significant from plot sizes ranging from 100 m to 1000 m in radius. The relationship between FTC and its natural enemies, which was postulated to underlie the effect of fragmentation on outbreaks in aspen forests, may be affected differently in northern hardwood forests, or other factors may be more important in determining outbreak duration in this forest type.     

日本落叶松体细胞胚胎发生相关基因LaSERK1的克隆与表达分析

本研究克隆了日本落叶松体细胞胚胎发生相关受体类蛋白激酶基因 LaSERK1,并检测了在不同培养条件下LaSERK1的表达情况,发现LaSERK1与已发现的其他物种SERK1 基因有高度相似性,qRT-PCR结果显示： LaSERK1在体胚发生早期高表达。结果表明：LaSERK1可能在落叶松体胚发育早期起重要作用,LaSERK1 也可能成为早期胚性细胞的标记基因。     

A century of riparian forest expansion following extreme disturbance: Spatio-temporal change in Populus/Salix/Tamarix forests along the Upper San Pedro River,Arizona, USA

Populus–Salix forests are a valued riparian vegetation type in western North America. These pioneer, obligate phreatophytes have declined on some rivers, raising conservation concerns and stimulating restoration plantings, but have increased on others. Understanding patterns and causes of forest change is essential for formulating conservation, restoration and management plans. Our goal was to assess spatio-temporal patterns of vegetation change on the Upper San Pedro River in semiarid Arizona, USA, one of the few undammed rivers in the region. Over 100 years ago, intense floods initiated channel incision and substantially altered hydrogeomorphology. Pioneer trees began to establish in the widening post-entrenchment zone as the surfaces began to stabilize. Using a time-series of aerial photographs (1955–2003) we quantified recent change in area of riparian cover types. Analysis indicated that wooded area in the post-entrenchment zone nearly tripled from 1955 to 2003, at the expense of bare ground, and the active channel narrowed appreciably. This forest expansion represents a long-term response to river entrenchment, with the temporal pattern influenced by recent flood cycles and biogeomorphic feedbacks. Populus–Salix have established episodically during the infrequent years with high winter flood runoff, sequentially filling available recruitment space. Older cohorts cover wide swaths of the floodplain while young trees form narrow bands lining the channel. Barring extreme flooding, the pioneer forests are expected to senesce over the coming century. An additional factor that has shaped the pattern of post-entrenchment forest expansion is anthropogenic water withdrawal. Populus–Salix forest increase has been greatest within a conservation area, where stream flows are largely perennial. In drier, agricultural sectors, Populus–Salix have declined while the more deeply-rooted Tamarix has increased. Overall, the study reveals that long-term fluctuations in pioneer forest area and age structure are common on dryland rivers, and shows how past events such as extreme floods can interact with recent environmental practices such as freshwater withdrawal to influence riparian forest patterns. This underscores the necessity of a long-term perspective for forest conservation and management.     

筛胸梳爪叩甲的防治技术研究

筛胸梳爪叩甲是我国南方地区重要的笋期害虫.研究了林间挖笋除虫、黑光灯诱杀及药剂防治3种方法对筛胸梳爪叩甲的控制效果.结果表明:3种技术措施均能显著降低该虫的危害率和虫口密度,其中药剂防治效果最明显.3 a持续挖笋除虫的防治效果达(22.76±3.90)％;每年单盏黑光灯年平均诱捕量可达(1 143.8±318.7)头,连续6 a的灯光诱杀可将竹笋危害率由防治前的(56.05±2.83)％降至防治后的(39.21±2.83)％;连续施用5％辛硫磷+3％毒死蜱颗粒剂3 a年可将竹笋危害率由防治前的(69.62±5.36)％降至(21.17±7.65)％,防治效果达(70.11±10.99)％.     

The utility of the predictive decapitation test as a tool for early genetic selection for Hypsipyla tolerance in big-leaf mahogany (Swietenia macrophylla King)

The plantation silviculture of mahogany (Swietenia spp.) has been severely limited by the attack of the mahogany shoot borer (Hypsipyla spp.), which greatly reduces or nullifies the commercial timber value of attacked trees by causing forking low on the stem. Selection for resistance, including tolerance (the capacity to retain apical dominance after attack), is widely considered to have potential as one element in an integrated pest management system. It has been suggested that the response of young seedlings to a predictive decapitation test might be useful as a means of detecting genotypes with high tolerance. This paper describes a pilot provenance/progeny experiment aimed at exploring this hypothesis. The number of shoots produced in response to attacks in the first year of field growth by Costa Rican material was found to be significantly correlated with response to decapitation in the nursery, on both individual tree and family mean bases. It appears, therefore, that the decapitation test could have a role in early selection for tolerance of Hypsipyla in mahogany. However, the presence of within-provenance genetic variation in response to Hypsipyla attack was not established.     

Antitrypanosomal activity of polycarpol from Piptostigma preussi (Annonaceae)

Polycarpol, sitosterol and sitosterol-3-O-β-D-glucoside isolated for the first time from Piptostigma preussi (Annonaceae) occur regularly in some Annonaceae such as Piptostigma genus. Polycarpol exhibits interesting antitrypanosomal activity with an ED₅₀ value of 5.11 µM on Trypanosoma brucei cells. Moreover, it inhibits T. brucei glycolytic enzymes GAPDH and PFK with IC₅₀ values of 650 and 180 µM respectively.     

双斑长跗萤叶甲对几种植物挥发物的触角电位和行为反应

采用触角电位(EAG)、"Y"型嗅觉仪和风洞的方法研究双斑长跗萤叶甲成虫对14种植物挥发物的电生理和行为反应,筛选出对双斑长跗萤叶甲有效的植物挥发物,为该害虫的种群监测和防控提供新技术。研究结果表明:稀释102、103倍的薄荷精油和1 mol.L-1的香叶醇能引发双斑长跗萤叶甲强烈的EAG反应(P<0.01),且嗅觉测试表明,薄荷精油(稀释102倍)对双斑长跗萤叶甲的最大驱避率为(74±5.47)%,香叶醇(1 mol.L-1)对双斑长跗萤叶甲的最大引诱率为(70±10.00)%。风洞行为趋性研究表明:稀释102倍的薄荷精油对双斑长跗萤叶甲的最大驱避率为(72±8.37)%,而1 mol.L-1的香叶醇对双斑长跗萤叶甲的最佳引诱率为(66±8.94)%。