首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 578 毫秒
1.
The olive is one of the most important crops in Greece as in many Mediterranean countries. Several insects are considered serious pests of the olive crop. In this study, we report two new pests for olive trees in Greece and possibly in the Mediterranean region: the quince moth Euzophera bigella (Zeller) (Lepidoptera: Pyralidae) and the olive leaf gall midge Dasineura oleae (F. Low) (Diptera: Cecidomyiidae). Although E. bigella is not considered a pest of olive trees, in the summer of 2011, the quince moth was recorded for the first time infesting olive trees in several orchards in the rural area of the Municipality of Amphipolis (Region of Central Macedonia). Infestation induced cracking and swelling symptoms on the bark of limbs and the periderm of trunks, accompanied by extensive internal bark necrosis, which caused the desiccation of limbs or even the death of whole trees. D. oleae has been reported infesting olive trees in Greece; however, it was not considered a pest of the crop. In February 2010, extensive infestations by D. oleae were detected in the coastal zone of Elounda, Lassithi (Region of Crete). Infestations were observed on the leaves causing elongate galls and deformations, while in highly infested trees defoliation was reported. Because of the scarceness of these infestations, the results reported in this study are discussed in relation to cases reported from other countries and/or on other crops. In addition, a review of the distribution, biology and control methods of these species is provided in an attempt to summarize the scattered information currently available.  相似文献   

2.
Psyttalia concolor is a parasitoid of fruit flies (Tephritidae) which is used to control the olive fruit fly (Bactrocera oleae). Detailed knowledge of its reproductive biology is required to optimise mass rearing conditions and use in biological control. In this study, the mating behaviour of P. concolor was investigated in order to understand the factors that can influence the success of male mating, using both high-speed video and biological assays. P. concolor males were more likely to be successful in mating during the early morning as opposed to the afternoon, and their courtship behaviour was not affected by the female mating status (i.e. virgin or mated). Wing fanning and copulation attempts were also frequently displayed among males, but male mating status did not influence male–male courtship behaviour. Video data revealed that during wing fanning, male wings were kept raised and moved rhythmically in a dorsoventral fashion. Frequency, pulse duration and interpulse interval of the fanning males during female courtship differed significantly in successful mating attempts compared to unsuccessful ones. Wingless males had significantly lower mating success compared to winged males, suggesting that wing fanning increases the likelihood of attracting a mate. Overall, the study increases the knowledge of the reproductive biology of P. concolor and suggests the importance of fanning behaviour among the range of sensory modalities used by this parasitoid in intra-specific communication.  相似文献   

3.
The purpose of this study is to investigate the biology of Cryphalus piceae (Ratz.) (Col., Scolytidae) living in Abies bornmülleriana (Mattf.) in fir forests in the Western Black Sea region in Turkey. The dates of swarming, tree attack, egg-laying, and different stages of development are given. The species had two generations per year.  相似文献   

4.
Abstract The biology of two important lepidopterous pests, Prays oleae Bernard and Palpita unionalis Hübner, was studied. The target pests were reared on olive plants, Oleae europaea L. (Oleaceae) under laboratory conditions for two successive generations, from March to June 2002. For P. oleae, the duration of larval stage development in the first generation was 21.4 ± 0.18 days at 19.3–20.9 °C, 65–68 % R.H, while in the second generation it was 14.8 ± 0.10 days at 20.8–24.2 °C, 65–69 % R.H. The number of eggs laid per female ranged from 58 to 109 eggs in the first generation, and from 47 to 113 in the second. The larval stage duration of P. unionalis was 16.3 ± 0.12 days at 16.8–22.9 °C, 65–69 % R.H. and 15.5 ± 0.12 days at 21.6–25.5 °C, 66–69 % R.H. for the first and second generations, respectively. Also, the number of eggs laid per female ranged from 630 to 653 eggs, and from 425 to 493 eggs in the second generation under the same previous laboratory conditions. P. oleae laid eggs at night mostly singly on flower-buds, more on the calyx. than on the petals. The larvae mined on leaves and damaged groups of flowers. P. unionalis adults were active at night, laid eggs singly at twilight usually on the lower surface of foliage. Larvae fed on leaves spinning several leaves together to form shelter for the pupa.  相似文献   

5.
The main purpose of this study was to establish whether sugi lumber with an extremely low Young’s modulus, which is plentifully produced in southern Japan, can be practically used as laminae for glued laminated timber (glulam) from the viewpoint of long-term performance under loading. Bending creep tests were carried out on sugi (Cryptomeria japonica D. Don) glulam with extremely low Young’s modulus laminae (3–4 kN/mm2) for the inner layers, as were tests on hybrid glulam with Douglas-fir (Pseudotsuga menziesii Franco) laminae (14–15 kN/mm2) for the outermost layer and sugi laminae (including those with a Young’s modulus of 3–4 kN/mm2) for the inner layers. The specimens were eight glulam beams with different compositions that were 105 mm wide, 210 mm deep, and 3980 mm long. The term of the creep test was 4 years. The results are summarized as follows. First, there were no significant differences between the Young’s modulus or bending creep of glulam L30 (laminae with Young’s modulus of 3–4 kN/mm2) and that of glulam L50 (laminae with Young’s modulus of 5–6 kN/mm2) for the inner layers. Second, for asymmetric compositions, the behavior of increases and decreases of relative creep due to atmospheric changes showed opposite behavior for glulam loaded from the side of lower Young’s modulus and from the side of higher Young’s modulus. Third, the required experimental term for the creep test to estimate an accurate long-term curve is 1 or 2 years (with data for the first 6 months excluded) when the power law is used for the estimation. Fourth, the values of relative creep in 50 years obtained from the experimental term were much lower than 2, which is the standard value set by Notification No. 1459 of the Ministry of Construction in Japan, and these values were not affected by the composition of the laminae.  相似文献   

6.

Introduction   

We examined the functional relationship between seed size and seedling performance in the valley oak (Quercus lobata Née) by means of a 13-year common garden experiment.  相似文献   

7.
Proteinase inhibitors are currently targeted as potential insect control agents, but adaptation to proteinase inhibitors is a recognized limitation to such approach requiring the understanding of how phytophagous species can cope with such compounds. The velvetbean caterpillar (Anticarsia gemmatalis) is a key pest of soybean and well-adapted to its host proteinase inhibitors, which is rich in serine-proteinase inhibitors, particularly trypsin-like proteinase inhibitors. As the expression of cysteine proteinases in the midgut of the velvetbean caterpillar is a potential adaptation to circumvent its host defense, we assessed and characterized the digestive cysteine-proteinase activity from velvetbean caterpillars. Significant soluble and membrane-bound proteolytic activity was obtained and was consistent with those of cysteine proteinases based on the substrate and inhibitors used for their characterization. The K m and V max values obtained were 2.35 ± 0.50 mM and 40.89 ± 6.68 nmol min−1 mg−1 for the soluble proteinases and 0.33 ± 0.03 mM and 24.54 ± 0.67 nmol min−1 mg−1 for the membrane-bound proteinases, range of values also consistent with cysteine proteinases. Therefore, the proteolytic activity observed in the velvetbean caterpillar midgut is consistent with that of cysteine proteinases providing preliminary support for the contention of their potential involvement mitigating the negative effects of serine-protease inhibitors in this species.  相似文献   

8.
The aim of the study is to compare selected theoretical distributions (normal, lognormal, Weibull, gamma, logistic, and exponential) in describing the tree diameter (DBH) distributions of mixed near-natural forests consisting of fir Abies alba Mill. and beech Fagus sylvatica L. growing in various vertical structures. Tree DBH data were collected between 1997 and 2008 from 51 sample plots established in the Świętokrzyski National Park in Poland. The empirical data represent differentiated DBH distributions, ranging from almost symmetric to extremely asymmetric ones. The chi-square test and the modified Kolmogorov–Smirnov test were chosen for the goodness-of-fit testing. In addition to the test statistics, the bias (B), the root mean square error (RMSE) and the graphical method (quantile–quantile plots) were used. In one-storied stands, the most suitable distributions were the normal and logistic distributions; in two-storied and multilayered stands, the Weibull and gamma distribution were the most suitable; and in selection stands, the exponential distribution was the most appropriate to describe the DBH distribution. The order of precision of the tested distributions (from the highest to the lowest) was Weibull, gamma, logistic, normal, exponential, and lognormal. The normal and exponential distribution should be applied only to one-storied and selection forests, respectively. The least suitable distribution for DBH distribution modelling was the lognormal one.  相似文献   

9.
We derived an allometric model of the height–diameter curve for even-aged pure stands, which was a modification of the earlier model proposed by Inoue (2000a). An individual-dependent allometric equation was used as the height–diameter curve. Using the discriminant analysis method, all trees composed of a stand were stratified into upper and lower trees. It was assumed that both relationships between mean tree height H m and upper tree height H u and between mean DBH D m and mean DBH of upper trees D u could be described by the time-dependent allometric power equations. The height–diameter curve showed an average relationship between tree height and DBH of a given stand at a given time, and hence it could be assumed that the height–diameter curve contained two points (D m , H m ) and (D u , H u ). With these assumptions, we derived an allometirc model of height–diameter curve, which allowed the coefficients of the curve to be estimated from mean tree height and mean DBH. The proposed model was fitted to Japanese cedar (Cryptomeria japonica D. Don) data. The error ratio of the allometric model ranged from 2.254% to 13.412% (mean = 6.785%), which was significantly smaller than that of the earlier model. When the error of mean tree height was ±1.0 m or less, the effect of the error of mean tree height on the error ratio was comparatively small. This suggested that the error of ±1.0 m in mean tree height could be accepted in the estimation of height–diameter curve using the allometric model. These features enable us to combine the allometric model with Hirata’s vertical angle-count sampling or growth models. In conclusion, the allometric model would be one of the most practical and convenient approaches for estimating the height–diameter relationship of even-aged pure stands.  相似文献   

10.
This work verifies the development threshold of the pupal stage of L. serricorne whose larva fed exclusively on dried tobacco leaves. In previous work, using the thermal constant equation, this threshold was found to be 13.8 °C and the thermal constant to range from 89.05 to 94.05 day-degrees (°C). Lower temperatures, 10.5±0.5, 11.5±0.5 and 12.5±0.5 °C, close to this threshold, were tested in the absence of light and at a relative humidity of 65±3% . It was found that no development of either larva or pupa exists below this threshold  相似文献   

11.
Stability analyses to evaluate site–family interaction for tree height at 15 years old were conducted in trials of open-pollinated families of hinoki (Chamaecyparis obtusa Endl.) plus trees established in the Honshu and Shikoku area of the Kansai Forest tree breeding region, Japan. The Honshu area included 103 sites (226 families), and the Shikoku area included 27 sites (62 families). Analyses of variance indicated that the interaction between site and family was not significant in the Honshu area, whereas in the Shikoku area the interaction was significant. The stability analyses regressed the family–site means against site means. The linear regression analysis was carried out using the data for 164 families that were tested at five or more test sites from the 130 test sites. Approximately 93% of families had values of linear regression coefficient that were not significantly different from unity. These results suggest that almost every open-pollinated family of hinoki plus trees have average stability and are equally well adapted to good and poor sites. The differences in the reaction of a family to site productivity are not the main causes of the interaction.  相似文献   

12.
  相似文献   

13.
The red flour beetle, Tribolium castaneum (Herbst), is one of the most serious secondary pests that feeds on a wide range of durable stored products including cereals, cereal products and other high value produce such as cocoa beans and dried fruits. Toxicity and protectant potential of Calneem® oil derived from the seeds of the neem tree Azadirachta indica A. Juss. towards T. castaneum were evaluated in stored wheat in the laboratory using contact toxicity, grain treatment, persistency, progeny emergence and repellency assays. Calneem® contains about 0.3% azadirachtin as its major active ingredient. The Calneem® was applied at six dosages (0.1, 0.2, 0.5, 1.0, 2.0 and 3.0% v/v). The oil was emulsified with water using 0.07% soap. All dosages of Calneem® oil were toxic and highly repellent to T. castaneum with an overall repellency in the range of 52–88%. The highest dosage of 3.0% of Calneem® oil tested killed at least 90% of the beetles within 72 h on grain, and 88% mortality was obtained on filter paper. T. castaneum mortality was dose dependent. The development of eggs to adults on cracked wheat was significantly (P < 0.05) inhibited by Calneem® oil treatments. The effectiveness of Calneem® oil was significantly reduced by the length of storage after application. The results obtained suggest good potential for the practical use of Calneem® oil as grain protectant for stored product pest control. The use of plant materials such as neem oil may be a safe, cost-effective method of grain preservation against pest infestation amongst low-resource poor farmers who store small amounts of grains.  相似文献   

14.
For the biological control Bemisia tabaci (Genn.) Biotype B (Homoptera: Aleyrodidae) , about 200,700 individuals of the imported parasitoid Eretmocerus hayati Zolnerowich and Rose (Hymenoptera: Aphelinidae) were released during 2000 and 2002 on different host plants in Egypt. The average parasitism rates in different governorates on Lantana camara, Gossypium barbadence (cotton), Helianthus annus (soybean) and Solanum melongena (eggplant) were 10.3 and 14%, 16 and 11.4%, 12.9 and 8.7%, 18 and 13% during 2001 and 2002, respectively. The population of E. hayati correlated significantly with the buildup of the whitefly population in all three governorates, which indicated the establishment of the E. hayati parasitoid on these economically important crops in Egypt.  相似文献   

15.
  • ? The objectives of this study were to measure litterfall production of the four floodplain forest types and to analyze the relationship between litterfall (forest type, dominant species, and organic fractions) and flood pulses.
  • ? Litterfall production was measured in two mono-specific stands of Salix humboldtiana or Tessaria integrifolia, respectively, and two mixed forests dominated by A. inundata or Nectandra angustifolia, during 1998 and the 2000–2002 periods.
  • ? Mono-specific stands presented similar productivities (6.8 and 6.5 Mg dry matter ha?1 y?1, respectively), but differed significantly from the two other. The highest litterfall production was obtained during the large flood that occurred during 1998, decreasing later throughout the study period. Leaves were the dominant fraction of litterfall, followed by branches, flowers, and fruits.
  • ? Only S. humboldtiana, T. integrifolia and A. inundata forests showed distinct patterns of litterfall production, depending on the flooding pulse. N. angustifolia did not show a distinctive litterfall pattern.
  • ? The forests studied here presented patterns of litter production associated with the flood pulse according to its location along a topographic gradient, that controls the litter productivity of these forests.
    •   相似文献   

    16.
    The study investigated the development, survivorship, and food intake of cotton leafworm Alabama argillacea (Hübner) fed on three cotton cultivars with colored fibers. Significantly shorter larval life-span and higher pupal weight as well as higher survival rates were observed in A. argillacea fed on leaves of BRS Safira and BRS Rubí cotton cultivars compared with the BRS 200 cultivar (BRS = Brazil). Weight gain, feces, and food intake were higher in A. argillacea fed on leaves of BRS Safira compared with the BRS 200 cultivar. The cotton cultivar significantly affected all larval food intake and utilization indices for A. argillacea. The larvae of A. argillacea were more efficient (higher efficiency in converting ingested (ECI) and digested (ECD) food) when fed on leaves of the BRS Safira cultivar in comparison to the BRS 200 cultivar, since the larval phase was shortened and food intake was higher, resulting in a higher growth rate (RGR). However, A. argillacea larvae fed on the leaves of the BRS 200 cultivar, with lower ECI and ECD, exhibited a compensatory response, extending the duration of the larval phase and increasing food intake, resulting in a higher relative metabolic rate. We conclude that BRS Safira provides the best food quality for A. argillacea, BRS 200 the worst, and BRS Rubi plants of intermediate quality.  相似文献   

    17.
    The “algarrobo” [Prosopis chilensis (Molina) Stuntz] is a tree species that represents an important natural resource in arid and semi-arid regions of Argentina. In this paper, we analysed and compared the variability of 46 RAPD (Random Amplified Polymorphic DNA) loci with previous estimates obtained from 12 isozyme markers in nine Argentinean populations of P. chilensis representative of the whole range of this species in Argentina. We evaluated the population structure and the existence of genetic variants associated with environmental variables. Expected heterozygosity (H e) estimated from RAPD varied significantly among populations and regions. Hierarchical analysis of genetic variability (AMOVA) showed that most (88.1%) of the total diversity occurs within populations, the component among populations within regions (9.3%) was intermediate, while the between-region component was the lowest (2.6%). All three variance components were highly significant. The MDS plot from pair-wise Φ ST matrix was consistent with the highly significant among-region differentiation indicated by the AMOVA. All 12 variable isozyme loci and 26 out of 46 RAPD loci showed significant or highly significant association with at least one geographic/climatic variable according to the stepwise multiple regression analysis. These results imply that the genetic differentiation among populations is better explained by environmental or biogeographical grounds than by geographical distances, suggesting gametic disequilibrium with loci responsible for the adaptation to particular environmental conditions. The information from RAPD markers would provide a relevant criterion to preserve genetic diversity in programmes for conservation and rationale use of this species.  相似文献   

    18.
    Interrelationships between self-thinning, biomass density, and plant form were mathematically modeled in relation to stand development in which self-thinning is either not occurring or is occurring. The relationship between biomass density and mean shoot mass is derived as a simple power function at the stage when self-thinning does not occur. When self-thinning occurs, constant biomass density is attained when the 3/2 power law of self-thinning applies and the allometric coefficient is assumed to be 1/3 in the allometry between mean plant height and aboveground mass. The applicability of this mathematical model and the allometric reformulations of the self-thinning exponent were tested using experimental data for dense populations of Chamaecyparis obtusa seedlings during the first 2 years of growth. On the basis of the results of the present model and experimental data, the dependence on competition of the mean height:diameter ratio, mean stem diameter, and leaf biomass density are discussed. As a result, the mean height:diameter ratio was almost asymptotically constant at the latter growth stage in the second-year seedlings, so that the 3/2 power law of self-thinning was held in the present analysis. However, the value of height:diameter ratio will become smaller in older stands, because tree height is considered to be asymptotic with respect to tree age due to hydraulic and other limits. Therefore, the present modeling implies that one of the reasons why the 3/2 power law from a geometric basis has been recently rejected depends on whether or not the height:diamter ratio is constant in older trees.  相似文献   

    19.
    The beginning of the land rent theory is closely related to the German forest economists Friedrich Wilhelm Leopold Pfeil and Johann Christian Hundeshagen (1828). It was further developed by Gottlob König (1864), Johann Heinrich v. Thünen, Max Robert Preßler, Gustav Heyer, Max Endres and in particular by Martin Faustmann (1849). His 1849 published and well known formula may be seen as the center of the land rent theory. However, the application of this concept demanded a considerable change of forest management practice due to the reduction of usual rotations and stocking density. Eventually, the land rent theory conflicted with the principle of sustained yield which had become the central idea of forestry in Germany in the 19th century. Since forestry under German conditions did not start as an investment on bare forest land, but had to manage existing forests under the principle of sustainability, the theory of the highest revenue seemed to be a more appropriate guideline for forestry. However, the maximization of the highest revenue assumed a marginal interest rate of 0% because the time span between input and output was not considered. Besides that, this principle also conflicted with the reality of forestry, because the scarcity of financial funds was not regarded. So far, both theories have not delivered solutions useful to real forest economic decision problems in Germany. Using an example from Lower Saxony, it is demonstrated that considering the objective of sustainability leads to results which are in accordance with the reality and the economic theory.  相似文献   

    20.
    Decaying mangrove detritus plays a significant role in nutrient cycling and fueling in both the forests and aquatic habitats where the detritus stems from estuarine and coastal food webs.Detrital decay rates partly depend on the type of detritus,but most studies have thus far focused on leaf litter decay and decomposition,whereas other detrital sources(except for roots)have largely been ignored.We compare the decay rates of Rhizophora apiculata and Xylocarpus granatum non-leafy detritus(flowers,propagules,stipules,and twigs)with mangrove leaf litter in field studies,using litter bags during the dry and the wet seasons in the tropical mangrove forest of Sibuti,Sarawak,Malaysia.We observed higher microbial decay rates of stipules,flowers,propagules,and twigs for both the R.apiculata and X.granatumduring the wet months.By contrast,leaf decay rates were higher during the dry months.Decay rates depended on the lignin content of the detrital sources of both species,both during dry and wet months.Accordingly,the half-life(T0.5)and 95%lifespan(T0.95)of non-leaf materials(flowers,propagules,stipules and twigs)for both species were remarkably longer than those of leaf litter.Slowly decaying non-leafy detritus may play a significant role in nutrient and carbon cycling over longer time,when leaf litter is either being decomposing rapidly and/or being washed away by tidal flush and river runoff.Hence,non-leafy(flowers,propagules,stipules and twigs)detritus should be taken into account when budgeting organic matter turnover in mangroves.  相似文献   

    设为首页 | 免责声明 | 关于勤云 | 加入收藏

    Copyright©北京勤云科技发展有限公司  京ICP备09084417号