Flowers for better pest control? Ground cover plants enhance apple orchard spiders (Araneae), but not necessarily their impact on pests

Effects of ground cover upon arboreal spiders and their ability to control pests were studied in an apple orchard over six years. The ground cover treatments were: (1) annual and perennial flowering herbs (FLOWER), (2) regularly mowed grass (GRASS) and (3) weed-free bare ground (BAREgr) in the alleys. Spider abundance and species richness increased significantly in FLOWER compared to BAREgr, with GRASS being intermediate between the other two treatments. The effects of ground cover vegetation varied across spider guilds and individual species. The number of stalkers (Salticidae) increased sharply with the amount of vegetation in the alleys, while the increase was much less steep in ambushers (mainly Thomisidae and Philodromidae), and we found no significant difference between the treatments in space web builders (Theridiidae) and orb web builders (mainly Araneidae). The spider community was dominated by the intraguild predator Carrhotus xanthogramma (Salticidae), which showed a 3.5-fold increase in FLOWER compared to BAREgr and represented 40, 54 and 63% of the total spider abundance in BAREgr, GRASS and FLOWER treatments, respectively. The other species were less numerous and their response to FLOWER compared to BAREgr treatments ranged from a ninefold increase to a sixfold decrease. Within potential prey groups, hymenopteran parasitoids, dipterans and Auchenorrhyncha were the best predictors of spider abundance. In contrast, the abundance of apple pests was independent of spider density and showed no difference between treatments, indicating that spiders in the studied orchard had little impact on the size of the pest populations. This study demonstrates that functional traits and abundances of spider guilds and species, rather than the total spider abundance per se, might explain the success or failure of spiders in conservation biological control.     

Towards Insecticide Free Apple Orchards: Flowering Plants to Attract Beneficial Arthropods

Tanacetum vulgare, Chrysanthemum maximum, Aster tongolensis and Achillea millefolium were planted to attract and retain predacious and parasitoid arthropods in a Quebec apple orchard. The plants covered one-third of the surface of the experimental block and provided nectar, pollen and refuge for beneficial arthropods. The parasitoid fauna increased several-fold during the study. The most important index of pest management in this study was the quality of the fruit at harvest and it attained 90.8% (clean fruit) in the fifth year of the study. The technique cannot be readily adopted into an orchard that is in full production because it would require several years to build up the beneficial arthropod fauna to an effective bio-control force. During that period, pesticides would not be applied and losses in yield would be commercially unacceptable. Habitat management should be used as a template for biological control of orchard pests over which other bio-control techniques can be superimposed to further increase the quality of the yield at harvest.     

Long-term effects of gypsiferous coal combustion ash applied at disposal levels on soil chemical properties

Currently, there is renewed interest in the agricultural utilization of coal combustion byproducts. Field sites where high rates (112 Mg ha^–1) of high gypsum coal combustion spent bed ashes were surface applied in 1980 within fruit tree orchard rows were identified and sampled with depth. The objective of this study was to examine the effects on long-term exposure/leaching of these materials on soil profile chemical properties. When applied, the material had an aqueous pH of 12.5 and consisted of about 52% calcium sulfate, 33% calcium oxide and 15% coal ash residues. Eleven years after ash application, soil pH is significantly higher in the top 66 cm of the treated sites compared to unamended sites. This has been accompanied by increases in extractable and total calcium and total boron and sulfur with a concomitant reduction in extractable magnesium. Remaining pieces of the applied spent bed material are composed primarily of calcite and quartz with some gypsum associated with large pieces.     

Flowers for better pest control? Effects of apple orchard groundcover management on mites (Acari), leafminers (Lepidoptera,Scitellidae), and fruit pests

Flowering companion plants provide nectar, pollen, alternative prey, shelter, and overwintering habitat for arthropod natural enemies and thus might increase their abundance and efficacy in pest control in agricultural fields. We report the results of a 6-year study on the effects of annual and perennial flowering herbs sown in alleys of an apple orchard on phytophagous and predacious mites, leafminer moths and their parasitoids and on pests causing fruit injury. Plots with weed-free bare ground and with regularly mowed grass served as controls. The abundance and diversity of predatory phytoseiid mites increased in the presence of flowering ground cover plants. However, this positive effect on phytoseiids was confined only to spring and autumn and intraguild predation (Typhlodromus pyri gradually displaced Amblyseius andersoni in the presence of flowers) also constrained their enhancement. Spider mites’ (Tetranychidae) abundance was low in all years and did not increase with the alley herb coverage. Incidence of the leafminer Leucoptera malifoliella was similar among the treatments despite the higher parasitism rate and parasitoid diversity in the plot with flowering herbs. We demonstrated that in the presence of flowering ground cover plants, the sex ratio of eulophid parasitoids' (mainly Chrysocharis pentheus) reared from L. malifoliella larvae and pupae shifted towards a male bias. Ground cover management had no effect on fruit injury caused by codling moth (Cydia pomonella) and summer fruit tortrix moth (Adoxophyes orana) and on the percentage of apples without insect damage.     

Use of Tropical Dry Forests and Agricultural Areas by Neotropical Bird Communities

Agricultural activities represent a global threat to biodiversity, yet little is known about the relative importance of different agricultural land uses in relation to their wildlife communities. We explored bird community structure, diversity, and composition in a landscape dominated by primary tropical dry forest, and in three agricultural systems (i.e., tree orchards, herbaceous cropfields, cattle pastures) to evaluate the way in which birds use different habitats within the landscape. Tropical dry forests had the highest species richness and community evenness, although the bird community in tree orchards was also relatively species rich and even. Cattle pastures had more bird species than cropfields but both habitats were comparatively species poor with low evenness. Our results are related to habitat structure and the spatial location of sites within the landscape matrix. Based on our observations, we recommend including native tree species within agricultural systems and surrounding areas to provide additional resources for birds. Finally, we suggest promoting natural recruitment of native trees and shrubs within cattle pastures to provide suitable habitat for species that use tropical dry forest plants. Abstract in Spanish is available at http://www.blackwell‐synergy.com/loi/btp .     

温度和气体成分对冬枣果实贮藏期间品质的影响

主要探讨冬枣(Ziziphus jujuba Mill. cv Dongzao)在-1 C的动态气调(CA-Ⅰ, 70% O2 0% CO2处理7天,然后转入5% O2 0% CO2中)、普通气调(CA-II, 5% O2 0% CO2;CA-III, 10% O2 0% CO2)及普通冷藏和常温(25C)等条件下,果实发病率、色素、可溶性固形物、可滴定酸、乙醇和乙酸乙酯含量等的变化。结果表明:与普通冷藏相比,气调贮藏能减缓果实的腐烂,抑制色素的分解和减少果肉中乙醇、乙酸乙酯的含量。动态高氧处理能有效地保持果实的颜色,抑制色素降解及果皮褐变。CA-Ⅲ (10% O2 0% CO2)能有效地减少果肉乙醇的含量而CA-Ⅱ(5% O2 0% CO2)能有效地减少果肉乙酸乙酯的含量。气调贮藏的果实可滴定酸及可溶性固形物含量与其他处理的果实没有明显的差异。     

Significance of shelter traps for spring monitoring of Anthonomus pomorum in apple orchards

The significance of the apple blossom weevil, Anthonomus pomorum L. (Coleoptera: Curculionidae), as a potential threat to apple, Malus domestica Borkh., has increased over the past two decades in many regions of Europe. The apple blossom weevil immigrates into orchards and colonises apple trees in early spring. Females deposit single eggs into closed blossom buds, which leads to capped blossoms. This study was designed to test the suitability of transparent shelter traps for the surveillance of colonisation under different population pressures, and to assess the quantitative relationship between number of weevils caught and: (1) absolute injury, expressed as number of infested buds, as well as (2) relative injury, expressed as a percentage of infested buds relative to all buds on the tree. The findings with the new shelter traps were contrasted to results from limb jarring. Numbers of weevils caught with the transparent shelter trap were positively correlated with absolute injury, as well as with relative injury across the five study sites, whereas weevil counts with limb jarring were not correlated with absolute injury, but only with relative injury. Our data validate the transparent shelter trap as a method for accurately monitoring the course of spring colonisation of A. pomorum and demonstrate its potential for predicting injury by the weevils to blossom buds. In contrast, the significance of limb jarring for monitoring both the time course of colonisation and subsequent injury is limited. The significant linear relationship between the number of weevils caught in shelter traps and the relative injury allows for predictions of potential damage before oviposition takes place, i.e., early enough for an insecticide application where necessary.     

枣及酸枣小孢子不同发育时期的花器形态与解剖特性研究

以枣(赞皇大枣、骏枣、苹果枣和梨枣)和酸枣为试材,对小孢子不同发育时期的花器形态与解剖特性进行研究.结果表明,小孢子单核晚期花蕾为黄绿色,花药为淡黄色,赞皇大枣花蕾横径为2.7mm左右,纵径为1.6mm左右;骏枣、苹果枣和梨枣花蕾横径范围为2.0mm左右,纵径范围为1.1～1.8mm;酸枣花蕾横径为1.9mm左右,纵径为1.0mm左右.在单倍体育种中,可依据花器官形态判别小孢子的发育时期,从而判别花药培养或小孢子培养的最佳取材时间.     

基于SRAP标记的紫溪山华山松种子园无性系遗传多样性分析

为明确云南楚雄市紫溪山华山松种子园内不同种源无性系间的遗传背景,该研究收集了园内6个种源的60个华山松无性系单株针叶,采用改良CTAB法提取其总DNA,并利用SRAP分子标记对其进行遗传多样性分析。结果表明:(1)从100对引物组合中共筛选出15对具有多态性的SRAP引物,经SRAP-PCR扩增后,共获得出194个位点,多态位点百分率(PPB)为85.05%,Nei’s基因多样性指数(H)为0.233 7,Shannon’s信息指数(I)为0.341 9,种源间的遗传分化系数(GST)为0.355 5。(2)华山松6个种源遗传多样性较高,且遗传变异主要存在于华山松种源内,种源地会泽(HZ)与巍山(WS)种源的遗传距离最近(D=0.050 1),会泽(HZ)与宜良(YL)种源的遗传距离最远(D=0.361 8)。(3)聚类分析显示将6个华山松种源一共聚为3类:会泽(HZ)和巍山(WS)种源聚为一类;楚雄(CX)、南华(NH)和宜良(YL)种源聚为一类;腾冲(TC)种源单独为一类。综合上述结果显示,紫溪山华山松种子园内无性系间的遗传分化处于较高水平,为华山松杂交育种时亲本的选配及种质资源的...