Tandem use of selective insecticides and natural enemies for effective,reduced-risk pest management

Selective chemical insecticides have become the dominant approach for management of recalcitrant and resistant insect pests, and the prospects for use of these chemicals in combination with biocontrol agents are on the rise. These chemical compounds, when used in combination with an effective natural enemy, may provide more comprehensive prophylactic and remedial treatments in the context of an integrated pest management program (IPM) than either approach alone. Many of these compounds have promise for a diversity of applications, including sustainable agriculture, control of urban pests, and invasive species eradication. Unfortunately, there are only a limited number of studies in which the effect of these insecticides on natural enemies has been examined. In this article, we examine the risk of several classes of insecticidal compounds to non-target animals, particularly natural enemies and pollinators, and review the most promising compounds for combined deployment with biological agents.     

A review of chemical control options for invasive social insects in island ecosystems

Social insects present unique challenges to chemically based management strategies, especially because fast‐acting compounds commonly applied for many pest insects may not be the most effective for colony elimination. The reproductive caste of a colony is the most protected from direct damage by insecticides, and compounds that cause rapid mortality among foragers frequently do not impact the reproductive members or even markedly reduce overall colony size. With recent bans on persistent insecticides that previously have been used to control social insects, especially termites, new compounds must be used. Island and coastal ecosystems are particularly sensitive to the effects of widespread pesticide use and concerns about unintentional water pollution and runoff are common, and international attention is being paid to developing sustainable pesticide options for agricultural and urban pest insects in particularly sensitive environments. Given the precarious status of many native insects and arthropods care must be taken to minimize exposure to potentially harmful insecticides and the non‐target impacts of these chemicals. However, recent developments in the synthesis and discovery of highly selective insecticides with low mammalian and non‐target toxicity provide viable alternatives to the broad‐spectrum persistent organochlorine insecticides that have been largely deregistered. Novel technologies, particularly synthetic analogues of biologically active compounds, yield new chemical control options and management strategies for island and other sensitive ecosystems; case studies from Australia, the Galapagos Islands and New Zealand highlight current challenges and successes.     

An evaluation of the mouse sperm morphology test and other sperm tests in nonhuman mammals. A report of the U.S. Environmental Protection Agency Gene-Tox Program

The literature on the mouse sperm morphology test and on other sperm tests in nonhuman mammals was reviewed (a) to evaluate the relationship of these tests to chemically induced spermatogenic dysfunction, germ-cell mutagenicity, and carcinogenicity, and (b) to make an interspecies comparison to chemicals. A total of 71 papers were reviewed. The mouse sperm morphology test was used to assess the effects of 154 of the 182 chemical agents covered. 4 other murine sperm tests were also used: the induction of acrosomal abnormalities (4 agents), reduction in sperm counts, (6 agents), motility (5 agents), and F1 sperm morphology (7 agents)). In addition, sperm tests for the spermatogenic effects of 35 agents were done in 9 nonmurine mammalian species; these included analyses for sperm count, motility, and morphology, using a large variety of study designs. For the mouse sperm morphology test, 41 agents were judged by the reviewing committee to be positive inducers of sperm-head shape abnormalities, 103 were negative, and 10 were inconclusive. To evaluate the relationship between changes in sperm morphology and germ cell mutagenicity, the effects of 41 agents on mouse sperm shape were compared to available data from 3 different mammalian germ-cell mutational tests (specific locus, heritable translocation, and dominant lethal). The mouse sperm morphology test was found to be highly sensitive to germ-cell mutagens; 100% of the known mutagens were correctly identified as positives in the sperm morphology test. Data are insufficient at present to access the rate of false positives. Although it is biologically unclear why one might expect changes in sperm morphology to be related to carcinogenesis, we found that (a) a positive response in the mouse sperm morphology test is highly specific for carcinogenic potential (100% for the agents surveyed), and (b) overall, only 50% of carcinogens were positive in the test (i.e., sensitivity approximately equal to 50%). Since many carcinogens do not produce abnormally shaped sperm even at lethal doses, negative findings with the sperm test cannot be used to classify agents as noncarcinogens. We conclude that the mouse sperm morphology test has potential use for identifying chemicals that induce spermatogenic dysfunction and perhaps heritable mutations. Insufficient numbers of chemicals agents have been studied by the other sperm tests to permit similar comparisons. A comparison of 25 chemicals tested with sperm counts, motility, and morphology in at least 2 species (including man, mouse and 9 other mammals) demonstrated good agreement in response among species. With further study, interspecies comparisons of chemically induced sperm changes may be useful for predicting and evaluating human effects.     

Effects of insecticides on behavior of adult Bactericera cockerelli (Hemiptera: Triozidae) and transmission of Candidatus Liberibacter psyllaurous

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is a serious pest of potatoes (Solanum tuberosum L.) that can cause yield loss by direct feeding on crop plants and by vectoring a bacterial pathogen, Candidatus Liberibacer psyllaurous. Current pest management practices rely on the use of insecticides to control the potato psyllid to lower disease incidences and increase yields. Although many studies have focused on the mortality that insecticides can cause on potato psyllid populations, little is known regarding the behavioral responses of the potato psyllid to insecticides or whether insecticides can decrease pathogen transmission. Thus, the objectives of this study were to determine the effects of insecticides on adult potato psyllid behaviors, the residual effects of insecticides on potato psyllid behaviors over time, and effects of these insecticides on Ca. L. psyllaurous transmission. Insecticides tested included imidacloprid, kaolin particle film, horticultural spray oil, abamectin, and pymetrozine. All insecticides significantly reduced probing durations and increased the amount of time adult psyllids spent off the leaflets, suggesting that these chemicals may be deterrents to feeding as well as repellents. Nonfeeding behaviors such as tasting, resting, and cleaning showed variable relationships with the different insecticide treatments over time. The insecticides imidacloprid and abamectin significantly lowered transmission of Ca. L. psyllaurous compared with untreated controls. The implications of our results for the selection of insecticides useful for an integrated pest management program for potato psyllid control are discussed.     

Role of receptors in human and rodent hepatocarcinogenesis

The liver is a major target organ in rodent carcinogenicity assays. Amongst the agents that are effective in producing rodent liver tumours are many chemicals which are not mutagenic, but are believed to mediate their effects by promoting the clonal outgrowth of initiated cells. Some of these chemicals, such as dibenzo-p-dioxins and certain PCBs, have been demonstrated to interact with specific cellular receptors and receptor binding appears crucial for their tumourigenic activity. Enzyme-altered foci in rat liver may serve as a sensitive means to estimate the promoting activity of these agents in rodents. Mechanistic considerations are of relevance when extrapolating these date from rodents to humans.     

昆虫抗药性机理：行为和生理改变及解毒代谢增强（英文）

杀虫剂抗性是指“生物的一个品系发展了对该生物正常种群中大多数个体具有致死作用剂量的杀虫药剂的能力”。行为改变、生理学上的变化或代谢解毒等抗性机制能够降低毒物到达靶标的有效剂量。行为抗性是指减少昆虫与毒物接触或使昆虫能够存活于对大多数对正常个体致死（或有害）的环境中的任何行为。生理学改变的机制包括杀虫剂对表皮的穿透性降低、增加对药剂阻隔（sequestration）或储存和加速杀虫剂的排泄。细胞色素P450、水解酶和谷胱甘肽S-转移酶是杀虫药剂代谢解毒的主要3大酶系。细胞色素P450是一个超基因家族,是生物体内对外源性和内源性化合物解毒代谢或活化最重要的酶系。在许多害虫中发现P450介导的解毒代谢增加导致了对杀虫药剂抗性的增加。谷胱甘肽S-转移酶是可溶性的 二聚体蛋白,与代谢解毒、大量内源性和外源性化合物的排泄有关,许多昆虫中证明其抗药性与该酶活性增加有关。水解酶实际上是一组异源的酶类,其对抗药性的作用包括通过基因扩增增加酶量,作为结合蛋白隔离杀虫药剂或通过增加酶的活性加强对药剂的水解作用。     

Recombinant viral insecticides: Delivery of environmentally safe and cost-effective products

Biological control agents such as baculovirus insecticides have many attributes which make them attractive alternatives to synthetic chemical pesticides. However, there have been several economic and agronomic barriers to their widespread use. Among the obstacles to commercialization of viral insecticides have been high production costs, the lack of efficacious formulation and application technologies, and a slow speed of action. Biotechnology has contributed several advances toward overcoming these obstacles. The high cost ofin vivo production can be reduced significantly using a newly developed high-density rearing system termed HeRD. The HeRD technology can be used to rear many different species of lepidopterous larvae for production of viral insecticides, as hosts for parasitoid production, or for sterile-male release programs. Using this technology, the baculovirus production costs are equivalent to sprayable Bt toxins. The field efficacy of viral pesticides and other biological control agents requires cost effective, biologically based formulation and application technologies. Based on current field efficacy evaluations of baculovirus pesticides, formulation/application technologies must be improved for viral pesticides to compete effectively and consistently in most pesticide markets. Through recombinant DNA technology, it is now possible to insert foreign pesticidal genes into viral pesticides, resulting in faster time to death or, more importantly, time to cessation of feeding of the target pests. However, the commercial use of recombinant pesticides has raised several potential environmental issues, including possible effects on non-target organisms, ecological interactions, mitigation and genetic stability. Genetic strategies have been developed to mitigate most of the potential problems associated with recombinant baculovirus pesticides. Five field tests have been conducted in the U.S. to evaluate these strategies. The laboratory and field results illustrate that the genetic strategies employed ensure environmental safety while also reducing production costs.     

Pest control in museums: toxicity of para-dichlorobenzene, ‘Vapona’™, and naphthalene against all stages in the life-cycle of museum pests,Dermestes maculatus Degeer,and Anthrenus verbasci (L.) (Coleoptera: Dermestidae)

Museums, herbaria, libraries and archival collections have traditionally relied on chemicals for the prevention and treatment of pest infestations. While current evidence suggests that the use of chemicals is declining, however, they are still found in many collections. The efficacy of three ‘insecticides’, para-dichlorobenzene, ‘Vapona’ and naphthalene (used in some museums to treat localized infestations and for their apparent residual benefit) against two insect species (Coleoptera: Dermestidae) was evaluated. Despite considerable variation in insect susceptibility, ‘Vapona’ was found in general, to be the most effective of the three chemicals used, particularly against larvae and adults. Naphthalene was the least effective, with low mortality rates recorded in the majority of the insect stages tested. Based on this study, an exposure/mortality relationship is presented for the prevention and treatment of insect infestations in museum and archival collections.     

Impacts of sublethal insecticide exposure on insects — Facts and knowledge gaps

The biodiversity and biomass of insects is dramatically declining due to various anthropogenic factors. One of these factors is the use of insecticides to protect plants from pests. However, apart from the targeted pest insects, thousands of non-target organisms face traces of insecticides that are not lethal but can affect numerous traits of the individual, including development, physiology, behaviour and communication. In the present review, key facts on impacts of sublethal insecticide exposure on such traits are summarised. Attributable to various abiotic and biotic processes, insecticide concentrations may become sublethal in space and time. Nevertheless, these concentrations impede insect development, reducing growth and survival, but sometimes also enhance reproductive performance. The effects are species-specific, but sensitivity also differs within species depending on the developmental stage, sex and population. Furthermore, insecticide exposure influences several immunity pathways and causes changes in behaviour. Such changes are mostly studied on the level of behavioural traits. However, also effects on the consistency of overall individual behavioural phenotypes, i.e. personalities, should be investigated, which have consequences on individual fitness and on the effectiveness of biocontrol agents. Moreover, insecticides can act as info-disruptors, impeding signal production and perception during chemical communication at various levels. Finally, microbial symbionts may modify insect responses to insecticides, being of particular interest for biotechnological approaches. Here, methodological issues are discussed and knowledge gaps and potential future research directions are highlighted. Understanding the mechanisms of dose-dependent insecticide impacts on organisms and their cascading effects on higher levels of biological organisation and on subsequent generations are of utmost importance for proper insecticide use.     

Plant essential oils: a substitute for conventional insecticides against Tribolium species (Coleoptera: Tenebrionidae)-achievements and challenges

Abstract

The literature on efficacy of plant essential oils and their constituents for the management of Tribolium spp. (T. castaneum and T. confusum), instigating infestation of a variety of stored grains and their products is reviewed here. Both species caused significant losses in the diverse food grains and their products through infestation. Essential oils of higher plants showed potential activity in the management of these infestation driven losses. Researchers have found that essential oils and their chemical constituents have significant toxicity against both the species of Tribolium via different modes of action like repellent, insecticidal, ovicidal, larvicidal, pupicidal, ovipositional and feeding deterrent actions. Concerning repellency and in vivo bioassays, few studies have been done with the essential oils against T. confusum, thus, more investigations are required to find the repellent agents against this insect. There are some essential oil-based botanical insecticides which have been proved effective for the protection of food grains from both beetles during storage. These botanical insecticides also exhibited behaviour altering properties against both beetles, thus, reducing the problem of pest resistance which is a problem with conventional insecticides. Therefore, essential oils-based botanical insecticides may be preferred option than conventional insecticides for protecting stored grains and their products against Tribolium infestation.     

Allelopathy in the natural and agricultural ecosystems and isolation of potent allelochemicals from Velvet bean (Mucuna pruriens) and Hairy vetch (Vicia villosa).

We have studied on allelopathy of plants and developed methods to identify the effective substances in root exudates, leaf leacheate, and volatile chemicals emitted from plants. We found traditional cover plants that show allelopathic activity are useful for weed control. It could eliminate the use of synthetic chemicals for this purpose. Allelopathy is a natural power of plants to protect themselves by producing natural organic chemicals. Some endemic plants in Asia, already known by farmers in the region, as either cover crops used in intercropping, hedgerow, or agroforestry, were found to possess strong allelopathic abilities. Our group identified several allelochemicals from these plants. These allelopathic cover crops, mostly leguminous plants, provide protein rich food, and grow easily without artificial fertilizers, herbicides, insecticides and fungicides. In this regards, these allelopathic cover crops could save food shortage in rural area, and are useful for environmental conservation. Screenings of allelopathic plants by specific bioassays and field tests have been conducted. Hairy vetch (Vicia villosa) and Velvet bean (Mucuna pruriens) are two promising species for the practical application of allelopathy. An amino acid, L-DOPA, unusual in plants, plays an important role as allelochemical in Velvet bean (Mucuna pruriens). Hairy vetch is the most promising cover plant for the weed control in orchard, vegetable and rice production and even for landscape amendment in abandoned field in Japan. We have isolated "cyanamide", a well known nitrogen fertilizer, from Hairy vetch. This is the first finding of naturally produced cyanamide in the world.     

Role of mermithid nematodes in biological control of mosquitoes

Mermithid nematodes have been reported from at least 63 species of mosquitoes from all over the world, but until recently they have received little attention. Such nematodes are prime candidates as biological control agents because they have adapted to the life cycle of the host; are host specific; produce high levels of parasitism; kill the hosts; are easily handled; have a high reproductive potential; are free swimming and can be disseminated easily in the infective stage; and can be used in an inundative or inoculative manner to control mosquitoes. Nevertheless, with the exception of one mermithid species, little is known about factors that influence parasitism in mosquitoes. Also, only one species of mermithid has been successfully mass cultured to date. The exception is the mermithid Reesimermis nielseni. With this mermithid, high levels of parasitism can be obtained in natural populations of mosquitoes at reasonable dosages; preparasitic nematodes can be applied easily by using many of the standard techniques used to apply insecticides; and R. nielseni can establish itself in many of the sites in which it is released. The same potentials exist for mermithids of other aquatic insects.     

Effects of environmental pollutants on the reproduction and welfare of ruminants

Anthropogenic pollutants comprise a wide range of synthetic organic compounds and heavy metals, which are dispersed throughout the environment, usually at low concentrations. Exposure of ruminants, as for all other animals, is unavoidable and while the levels of exposure to most chemicals are usually too low to induce any physiological effects, combinations of pollutants can act additively or synergistically to perturb multiple physiological systems at all ages but particularly in the developing foetus. In sheep, organs affected by pollutant exposure include the ovary, testis, hypothalamus and pituitary gland and bone. Reported effects of exposure include changes in organ weight and gross structure, histology and gene and protein expression but these changes are not reflected in changes in reproductive performance under the conditions tested. These results illustrate the complexity of the effects of endocrine disrupting compounds on the reproductive axis, which make it difficult to extrapolate between, or even within, species. Effects of pollutant exposure on the thyroid gland, immune, cardiovascular and obesogenic systems have not been shown explicitly, in ruminants, but work on other species suggests that these systems can also be perturbed. It is concluded that exposure to a mixture of anthropogenic pollutants has significant effects on a wide variety of physiological systems, including the reproductive system. Although this physiological insult has not yet been shown to lead to a reduction in ruminant gross performance, there are already reports indicating that anthropogenic pollutant exposure can compromise several physiological systems and may pose a significant threat to both reproductive performance and welfare in the longer term. At present, many potential mechanisms of action for individual chemicals have been identified but knowledge of factors affecting the rate of tissue exposure and of the effects of combinations of chemicals on physiological systems is poor. Nevertheless, both are vital for the identification of risks to animal productivity and welfare.     

微生物在水环境污染物降解中的应用

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中, 因此, 地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂、除草剂、烃等)的严重挑战, 特别是近年来随着集约化养殖的发展, 废水污染问题日益突出, 并且随着分析手段的进步, 能够检测到被排入水环境中的化学污染物质也越来越多, 这些化学污染物对水环境中的生物产生有害影响。但是, 微生物在污染控制上具有许多重要的作用。因此, 本文对微生物在水环境污染物降解中的应用进行了评论。结果表明微生物主要是应用在水产养殖水中, 而在其它的水体系(如河、湖、海)的应用较少。     

Control of insecticide exposure in employment; a guide to physicians for dealing with organic phosphates

Increasingly larger amounts of the highly efficient and highly toxic organic phosphate insecticides, particularly parathion, tetraethyl pyrophosphate, and Systox (demeton), are being applied on California's farms. These insecticides have become an economic necessity to agriculture. They can be used safely when rigid precautions are utilized and when medical supervision is provided for employees regularly working with these chemicals. The demand for the services of physicians prepared to supply this kind of industrial medical supervision is expected to increase in California. The basic procedures through which effective medical supervision can be provided are outlined.     

微生物在水环境污染物降解中的应用（英文稿）

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中, 因此, 地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂、除草剂、烃等)的严重挑战, 特别是近年来随着集约化养殖的发展, 废水污染问题日益突出, 并且随着分析手段的进步, 能够检测到被排入水环境中的化学污染物质也越来越多, 这些化学污染物对水环境中的生物产生有害影响。但是, 微生物在污染控制上具有许多重要的作用。因此, 本文对微生物在水环境污染物降解中的应用进行了评论。结果表明微生物主要是应用在水产养殖水中, 而在其它的水体系(如河、湖、海)的应用较少。     

Streptomyces genetics: a genomic perspective

Streptomycetes are gram-positive, soil-inhabiting bacteria of the order Actinomycetales. These organisms exhibit an unusual, developmentally complex life cycle and produce many economically important secondary metabolites, such as antibiotics, immunosuppressants, insecticides, and anti-tumor agents. Streptomyces species have been the subject of genetic investigation for over 50 years, with many studies focusing on the developmental cycle and the production of secondary metabolites. This information provides a solid foundation for the application of structural and functional genomics to the actinomycetes. The complete DNA sequence of the model organism, Streptomyces coelicolor M145, has been published recently, with others expected to follow soon. As more genomic sequences become available, the rational genetic manipulation of these organisms to elucidate metabolic and regulatory networks, to increase the production of commercially important compounds, and to create novel secondary metabolites will be greatly facilitated. This review presents the current state of the field of genomics as it is being applied to the actinomycetes.     

微生物在水环境污染物降解中的应用

每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中,因此,地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂,除草剂、烃等)的严重挑战,特别是近年来随着集约化养殖的发展,废水污染问题日益突出,并且随着分析手段的进步,能够检测到被排入水环境中的化学污染物质也越来越多,这些化学污染物对水环境中的生物产生有害影响.但是,微生物在污染控制上具有许多重要的作用.因此,本文对微生物在水环境污染物降解中的应用进行了评论.结果表明微生物主要是应用在水产养殖水中,而在其它的水体系(如河、湖、海)的应用较少.     

CONTROL OF INSECTICIDE EXPOSURE IN EMPLOYMENT—A Guide to Physicians for Dealing with Organic Phosphates

Increasingly larger amounts of the highly efficient and highly toxic organic phosphate insecticides, particularly parathion, tetraethyl pyrophosphate, and Systox (demeton), are being applied on California''s farms. These insecticides have become an economic necessity to agriculture. They can be used safely when rigid precautions are utilized and when medical supervision is provided for employees regularly working with these chemicals.The demand for the services of physicians prepared to supply this kind of industrial medical supervision is expected to increase in California.The basic procedures through which effective medical supervision can be provided are outlined.