Prospects for biopesticides for aphid control

Diseases form an important component of the natural enemy complex of aphids. The most common and obvious of these diseases are entomophthoran fungi such asErynia neoaphidis Remaudiere & Herbert,Entomophthora planchoniana Cornu,Zoophthora radicans (Brefeld) Batko andConidiobolus obscurus (Hall & Dunn) Remaudiere & Keller. The pest status of some aphids such as the pea aphid,Acyrthosiphon pisum (Harris), is considerably reduced by natural epizootics of fungal disease. However, disease may contribute little to practical control as it is mainly effective in high density populations when weather conditions are suitable. Introduction of exotic diseases for classical biological control is only rarely possible since most diseases, like their aphid hosts, are distributed world-wide. One exception was the successful introduction into Australia of a strain ofZ. radicans for control of spotted alfalfa aphid,Therioaphis trifolii (Monell) f.maculata in 1979. Attempts to manipulate entomophthoran fungi have had limited success because of problems with mass production, the fragility of the conidia and the need for suitably moist conditions. Hyphomycete fungi such asVerticillium lecanii (Zimm.) Viegas,Metarhizium anisopliae (Metsch.) Sorokin,Beauveria bassiana (Bals.) Vuill. andPaecilomyces spp. are more suitable for development as mycoinsecticides as they are cheap to mass produce and form stable conidia. “Vertalec?”, a formulation ofV. lecanii, has been sold in small quantities commercially in Britain and parts of Europe for many years and used mainly in glasshouses. Recently promising results have been obtained with use ofM. anisopliae for control of lettuce root aphid,Pemphigus bursarius (L.) in the UK. Laboratory studies on selected isolates ofB. bassiana andPaecilomyces spp. show a promising level of activity. Problems may occur with these species as they can kill aphid predators such as coccinelids. In addition, more research is needed on developing improved formulations which enable control to be achieved under low humidity conditions.     

Diapause induction in aphid parasitoids

Diapause is one of the adaptations that insects have evolved for the synchronisation of their life cycle with seasonal climatic changes and resources. In aphid parasitoids, univoltine species have an obligatory, genetically determined diapause. Polyvoltine species, on the other hand, use a variety of abiotic (temperature, photoperiod) and biotic (host insect or/and host plant) signals for the induction of diapause. We present an overview of the role of these environmental cues in diapause induction in specialist and generalist aphid parasitoids, and discuss possible endocrine factors that may be involved in diapause induction.     

Relative importance of predators and parasitoids for cereal aphid control

Field experiments with manipulations of natural enemies of plant-feeding insects may show how a diverse enemy group ensures an important ecosystem function such as naturally occurring biological pest control. We studied cereal aphid populations in winter wheat under experimentally reduced densities of: (i) ground-dwelling generalist predators (mostly spiders, carabid and staphylinid beetles); (ii) flying predators (coccinellid beetles, syrphid flies, gall midges, etc.) and parasitoids (aphidiid wasps), and a combination of (i) and (ii), compared with open controls. Aphid populations were 18% higher at reduced densities of ground-dwelling predators, 70% higher when flying predators and parasitoids were removed, and 172% higher on the removal of both enemy groups. Parasitoid wasps probably had the strongest effect, as flying predators occurred only in negligible densities. The great importance of parasitism is a new finding for aphid control in cereal fields. In conclusion, a more detailed knowledge of the mechanisms of natural pest control would help to develop environmentally sound crop management with reduced pesticide applications.     

恒毅力养成：针对城市学龄前儿童的一种自然教育

恒毅力是一种基础性的人格特征。恒毅力对于人一生的健康和福祉都有着重要的积极影响。大量研究证明接触自然对当代人恒毅力的养成有显著的促进作用。根据人类身心发展的规律,以恒毅力为主要目标的自然教育最好从学龄前儿童期（5~6岁）开始进行。遗憾的是,关于此类自然教育的理论及实践知识仍然处于分散和不足的状态。因而,发展相对完整的自然教育体系以培养学龄前儿童的恒毅力是十分紧急且重要的。从恒毅力自然教育的理论框架、关键要素及其权重、自然教育及体验活动智库、对自然教育场所及活动的策略性设计这4部分探讨该类自然教育的理论体系和实践策略,或可为研究者提供儿童恒毅力的未来研究趋势,为教育者提供自然教育的实践启示,为设计师提供自然体验的新思路。     

Visitor Perceptions of Nature Conservation at Helsinki Zoo

These days zoos often claim that their main objective is the promotion of nature conservation and that they strive to educate their visitors about animals and nature conservation. But how do zoo visitors themselves perceive this emphasis on conservation education? In order to determine how Helsinki Zoo visitors perceive nature conservation during their visit, we undertook a qualitative analysis of 75 structured situational interviews and five autoethnographical visits. Our results show that there was only a limited understanding of nature conservation among the zoo visitors. Their perception follows the typical framing of nature conservation in zoos: conservation projects that embrace captive breeding, in-situ conservation collaboration, and the reintroduction of those species. Moreover, in the Helsinki Zoo case these perceptions may have been influenced by the fact that the zoo did not give concrete advice on how the visitors themselves can contribute to conservation, except in terms of donating money. Framing nature conservation in such ways distances it from visitors’ everyday lives.     

樱桃瘿瘤头蚜的发生和防治

樱桃瘿瘤头蚜是樱桃春季的主要害虫之一,该蚜在豫西地区每年发生１０－１４代,以受精卵在小枝条的芽腋等处赵冬。越冬卵孵化盛期为落花后至第一片叶展开际,这是防治的有利时机,其防治方法是：（１）４月下旬人工摘除虫叶并集中销毁;（２）喷洒２．５％功夫乳油２５００倍稀释液,缺水地区则用４０％氧乐果乳油５倍稀释液涂干,其保叶效果均在９０％以上。     

Local Tree Mapping: A Collaborative,Place-Based Activity Integrating Science,Technology, Math,and Geography

This inquiry-based activity designed for the fifth through 12th grade allows students to engage in an outdoor, place-based experience, working collaboratively both in groups and as a class to accomplish the class goal of creating a local tree map linked to student-collected data about each tree. During Local Tree Mapping, students explore the local trees in the yard or neighborhood of the school, while learning basic skills in geographical information systems and Microsoft Excel. Through this activity, students gain a deeper understanding of and appreciation for the role of trees within the Earth's ecosystems, as they collect data on tree type, height, diameter, age, and the longitude and latitude of the trees. An extension activity is described in which students can enter their tree data into a carbon dioxide (CO₂) emissions reduction calculator to determine how much CO₂ is sequestered by the trees in their research site. Local Tree Mapping provides an opportunity for students to gain inquiry skills in science, mathematics, and geography as they participate firsthand in the collection, analysis, and presentation of real-world data that can be utilized by the local community.     

Biology Curriculum Development in Malawi

The effect of the introduction of the National Curriculum on ecology teaching in England and Wales is assessed. The ecological content of the new curriculum is compared with practising ecologists' views of what constitutes ecology.     

Potential for biotic interference of a classical biological control agent of the soybean aphid

The degree to which resident biota can inhibit the ability of an introduced biological control agent to establish and be effective is termed biotic interference. Studying biotic interference prior to a release using the actual agent is logistically difficult, however, due to quarantine restrictions. An alternative solution is to study biotic interference against a surrogate species in the intended range of introduction, with the expectation that biotic interference against the actual agent will be similar. This study assessed how biotic interference, mostly by generalist predators, may affect establishment of classical biological control agents of the soybean aphid, Aphis glycines Matsumura, in North America. The parasitoid Aphidius colemani Viereck was used as a surrogate for Asian aphidiine braconids such as Binodoxys communis (Gahan). We conducted a factorial field experiment that measured the effect of releasing A. colemani and of excluding resident natural enemies using field cages on soybean aphid populations. We also conducted molecular gut-contents analyses on predators collected in release plots to determine which species fed upon A. colemani. Releasing A. colemani in open field plots increased soybean aphid control beyond that observed in open field plots alone, despite indications that intraguild predation of A. colemani occurred. Thus, biotic interference was not sufficient to eliminate the contribution of A. colemani on soybean aphid suppression during the course of our experiment. Molecular gut-contents analysis revealed that at least two predators, Harmonia axyridis (Pallas) and Chrysoperla carnea Stephens, engaged in intraguild predation against A. colemani. The prolonged effect of intraguild predation on parasitoid establishment remains to be determined.     

大豆蚜的生物学防治技术

大豆蚜AphisglycinesMatsumura是亚洲大豆种植区的一种主要农业害虫。近年来,大豆蚜又先后侵入北美洲和大洋州等地,对当地的大豆生产构成了潜在威胁,正成为一种世界性的农业害虫。文章对大豆蚜的分布、危害、生物学特征、天敌和防治技术等方面的研究现状进行了详细论述。     

田间不同防治方法对麦蚜种群动态的影响

【目的】从保护生态环境兼顾防治害虫的角度出发,研究不同防治方法对麦蚜种群动态的影响,为麦蚜的田间防治提供理论依据。【方法】本试验分别设置不同的麦蚜防治田(空白对照田、黄板田、糖醋液田、诱芯田、诱虫灯田、综合防治田),在小麦生长期观察不同的防治田内麦蚜的种群动态的变化。【结果】诱虫灯对有翅蚜的防治效果要好于黄板和糖醋液,但对禾谷缢管蚜Rhopalosiphum padi(Linnaeus)有翅蚜的诱捕效果不明显,黄板和糖醋液对有翅蚜和无翅蚜均有防治效果,多种防治方法共同利用对麦蚜种群数量有一定的防治效果。【结论】多种防治方法共同使用的防治效果优于单一防治方法,诱虫灯、糖醋液、黄板、诱芯对不同种类麦蚜的防治效果不同。在田间使用时应注意不同时期采用不同的防治方法。