首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5篇
  免费   0篇
综合类   1篇
基础理论   1篇
污染及防治   3篇
  2013年   3篇
  2008年   1篇
  2006年   1篇
排序方式: 共有5条查询结果,搜索用时 781 毫秒
1
1.
Abstract: Coffee farms can support significant biodiversity, yet intensification of farming practices is degrading agricultural habitats and compromising ecosystem services such as biological pest control. The coffee berry borer (Hypothenemus hampei) is the world's primary coffee pest. Researchers have demonstrated that birds reduce insect abundance on coffee farms but have not documented avian control of the berry borer or quantified avian benefits to crop yield or farm income. We conducted a bird‐exclosure experiment on coffee farms in the Blue Mountains, Jamaica, to measure avian pest control of berry borers, identify potential predator species, associate predator abundance and borer reductions with vegetation complexity, and quantify resulting increases in coffee yield. Coffee plants excluded from foraging birds had significantly higher borer infestation, more borer broods, and greater berry damage than control plants. We identified 17 potential predator species (73% were wintering Neotropical migrants), and 3 primary species composed 67% of migrant detections. Average relative bird abundance and diversity and relative resident predator abundance increased with greater shade‐tree cover. Although migrant predators overall did not respond to vegetation complexity variables, the 3 primary species increased with proximity to noncoffee habitat patches. Lower infestation on control plants was correlated with higher total bird abundance, but not with predator abundance or vegetation complexity. Infestation of fruit was 1–14% lower on control plants, resulting in a greater quantity of saleable fruits that had a market value of US$44–$105/ha in 2005/2006. Landscape heterogeneity in this region may allow mobile predators to provide pest control broadly, despite localized farming intensities. These results provide the first evidence that birds control coffee berry borers and thus increase coffee yield and farm income, a potentially important conservation incentive for producers.  相似文献   
2.
3.
Abstract

Air permeation trials were conducted with Z,Z and E,Z isomers of 3,13‐octadecadien‐1‐ol acetate (ODDA) to determine response difference between males of the peachtree borer (PTB), Synanthedon exitiosa (Say), and lesser peachtree borer (LPTB), S. pictipes (Grote & Robinson), within and adjacent to permeated plots of a peach orchard. The pheromone was released from hollow fiber dispensers attached to the trees in the orchard.

In the pheromone‐treated plots, both E,Z and Z,Z‐ODDA significantly reduced trap captures of PTB relative to the untreated plot. The E,Z isomer also significantly reduced captures of LPTB males but captures in the Z,Z treatment were higher than in the untreated plots. The pheromone treatments also influenced trap capture of both PTB and LPTB male moths outside the permeated plots.  相似文献   
4.
Males of five species of three tribes in the longhorned beetle subfamily Cerambycinae produce volatile pheromones that share a structural motif (hydroxyl or carbonyl groups at carbons two and three in straight-chains of six, eight, or ten carbons). Pheromone gland pores are present on the prothoraces of males, but are absent in females, suggesting that male-specific gland pores could provide a convenient morphological indication that a species uses volatile pheromones. In this article, we assess the taxonomic distribution of gland pores within the Cerambycinae by examining males and females of 65 species in 24 tribes using scanning electron microscopy. Gland pores were present in males and absent in females of 49 species, but absent in both sexes of the remaining 16 species. Pores were confined to indentations in the cuticle. Among the species that had male-specific gland pores were four species already known to produce volatile compounds consistent with the structural motif. These findings support the initial assumption that gland pores are associated with the production of pheromones by males. There were apparently no taxonomic patterns in the presence of gland pores. These findings suggest that volatile pheromones play an important role in reproduction for many species of the Cerambycinae, and that the trait is evolutionarily labile.  相似文献   
5.
Indoxacarb was applied at 75 and 150 g a.i. ha? 1 for two years to an eggplant (Solanum melongena L.) crop grown in the field plots in order to evaluate its efficacy for management of the lepidopteron pest, shoot and fruit borer. The residues of the insecticide were quantified by high-pressure liquid chromatography (HPLC). The mean initial deposits of indoxacarb on eggplant fruits were found to be 2.60–2.634 mg kg? 1 and 3.64–3.68 mg kg? 1 from the two rates of applications, respectively. They declined with time and reached to non-detectable (< 0.02 mg kg? 1) after 15–20 d. Residues dissipated with a half-life of 3.0–3.8 d from both first and second-year application. A 3 d waiting period for harvest of fruits after insecticide application and processing resulted in the residue levels that were below the Codex maximum residue limit (MRL) of 0.5 mg kg? 1 thereby achieving a maximum safety and minimum risk to consumers. The best combination of chemicals for decontamination of indoxacarb was found to be by washing with a mixture of alkali and potassium permanganate (KMnO4) thereby resulting in the removal of 67.5% and 59.2 % residues for 5 and 10 μ g g? 1 spiking doses, respectively. Major products formed on reaction of indoxacarb with alkali were identified by electron spray ionization chromatography/mass spectrometry (ESI/MS). The per cent reduction on the weight and number basis of treated eggplant plots were compared to those observed in control plots to demonstrate the effectiveness of indoxacarb treatment on shoot and fruit borer population.  相似文献   
1
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