Insecticide‐induced hormesis and arthropod pest management

Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide‐induced hormesis within entomology and acarology. Hormesis describes a biphasic dose–response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide‐induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide‐induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas. © 2013 Society of Chemical Industry     

Can poisons stimulate bees? Appreciating the potential of hormesis in bee–pesticide research

Hormesis, a biphasic dose response whereby exposure to low doses of a stressor can stimulate biological processes, has been reported in many organisms, including pest insects when they are exposed to low doses of a pesticide. However, awareness of the hormesis phenomenon seems to be limited among bee researchers, in spite of the increased emphasis of late on pollinator toxicology and risk assessment. In this commentary, we show that there are several examples in the literature of substances that are toxic to bees at high doses but stimulatory at low doses. Appreciation of the hormetic dose response by bee researchers will improve our fundamental understanding of how bees respond to low doses of chemical stressors, and may be useful in pollinator risk assessment. © 2015 Society of Chemical Industry     

昆虫病原真菌在害虫防治中对天敌生物的影响研究进展

昆虫病原真菌是一类重要的微生物杀虫剂,广泛应用于农林害虫的生物防治。由于寄主范围广和主动侵染的特点,昆虫病原真菌在侵染、致死靶标害虫的同时,对包括天敌昆虫在内的非靶标节肢动物等会产生潜在的致病或亚致死风险。本文总结了昆虫病原真菌在害虫防治中的研究进展及对天敌生物的影响,并展望了昆虫病原真菌作为极具潜力的生物农药与天敌生物联合防治害虫的未来发展方向。     

Pesticide use,arthropod fauna and fruit damage in apple orchards in a Nordic climate

BACKGROUND

Integrated pest management (IPM) has a long history in fruit production and has become even more important with the implementation of the EU directive 2009/128/EC making IPM mandatory. In this study, we surveyed 30 apple orchards in Norway for 3 years (2016–2018) monitoring pest- and beneficial arthropods as well as evaluating fruit damage. We obtained growers’ diaries of pest management and used these data to study positive and negative correlations of pesticides with the different arthropod groups and damage due to pests.

RESULTS

IPM level had no significant effects on damage of harvested apples by arthropod pests. Furthermore, damage by arthropods was mainly caused by lepidopteran larvae, tortricids being especially important. The number of insecticide applications varied between 0 and 3 per year (mean 0.8), while acaricide applications varied between 0 and 1 per year (mean 0.06). Applications were often based on forecasts of important pest species such as the apple fruit moth (Argyresthia conjugella). Narrow-spectrum insecticides were commonly used against aphids and lepidopteran larvae, although broad-spectrum neonicotinoid (thiacloprid) insecticides were also applied. Anthocorid bugs and phytoseiid mites were the most abundant natural enemies in the studied orchards. However, we found large differences in abundance of various “beneficials” (e.g., lacewings, anthocorids, parasitic wasps) between eastern and western Norway. A low level of IPM negatively affected the abundance of spiders.

CONCLUSION

Lepidoptera was found to be the most important pest group in apple orchards. Insecticide use was overall low, but number of spray applications and use of broad-spectrum insecticides varied between growers and regions. IPM level did not predict the level of fruit damage by insects nor the abundance of important pests or most beneficial groups in an apple orchard. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

药剂诱导稻飞虱再猖獗及科学用药

稻飞虱是典型的再猖獗型重大害虫。害虫再猖獗包括生态再猖獗和生理再猖獗,前者主要由药剂杀伤天敌使天敌功能崩溃引起,后者指药剂刺激害虫生殖导致害虫增殖倍数显著增加。刺激稻飞虱生殖的药剂包括大部分有机磷、菊酯类、氨基甲酸酯类杀虫剂,及一些除草剂和杀菌剂(如井冈霉素、多菌灵)等。通过蛋白质组学、转录组学、基因表达谱分析及基因沉默试验证实化学药剂刺激稻飞虱生殖主要涉及与生殖和代谢相关基因的上调表达,但同一药剂对稻飞虱组团物种产生物种间基因功能生态位分离。这就需要在深入理解化学农药对生态系统中组团物种的正负效应和生殖影响的基础上进行精准用药技术设计。本文综述了一些农药对稻田害虫天敌行为、生殖、捕食功能及稻飞虱生殖影响的机理,并基于同种药剂对稻飞虱组团内不同物种生殖的相反效应,提出稻飞虱多物种共存时的科学用药技术。     

Variability of hormetic dose responses of the antiauxin PCIB on Lactuca sativa in a plant bioassay

Some herbicidal agents that damage plants at high doses stimulate their growth at low doses. This phenomenon of hormesis constitutes an alternative possible use of herbicidal agents that is, however, compromised by the apparent variability of the phenomenon. However, studies demonstrating and quantifying this apparent variability are lacking. The auxin‐inhibitor PCIB [2‐(p‐chlorophenoxy)‐2‐methylpropionic acid] was therefore investigated to determine whether interassay variability of stimulatory effects exceeds those of inhibitory effects and which hormetic quantity is most variable. Reparameterisation of the dose–response model used to estimate the hormetic dose range allowed including this feature as an explicit parameter. In bioassays with lettuce and root length as response variable, the variability of PCIB effects was evaluated in 33 complete dose–response assays. In a meta‐analysis, the occurrence of PCIB hormesis proved highly reproducible. However, the variability of effects was dose‐dependent and increased with decreasing dose. The response before the maximum stimulatory response and the absolute magnitude of hormesis proved most variable. Comparing the frequency distribution of effective doses demonstrated there was a risk of a previously hormetic dose causing a loss of hormesis or inhibitory effects in a subsequent experiment. Therefore, selecting a hormetic dose that will induce hormesis under any circumstances will be a major challenge.     

Implications of potential global warming on agricultural pests in Australia1

The potential influence of climate warming on the future status of agricultural pests in Australia is discussed in terms of the possible effects that changes in temperature, rainfall and weather patterns will have on the future distribution, numbers, fluctuations and movements of pest populations. Event-driven outbreaks are distinguished from rate-driven processes in pest populations. The future severity and frequency of pest outbreaks will depend on changes in the frequency of extreme weather events, some of which are related to the El Niño/Southern Oscillation phenomenon. Three scenarios are presented for geographical changes to rate-driven and to event-driven processes: little change (displacement of agroecosystems and their associated pests to new climatic optima); expansion of tropical pests, contraction of Mediterranean (winter rainfall) pests; increased pest multiplication in geographically fixed agroecosystems such as irrigation schemes and some animal production systems. There is considerable uncertainty about the future severity of outbreaks and chronic infestations because of our current difficulties in forecasting and realistically simulating population changes in agroecosystems. This probably results from the complex feedback mechanisms involving natural enemies and other factors. In Australia the overall expansion of areas affected by tropical pests portends an overall worsening of agricultural pest problems.     

United States Department of Agriculture-Agricultural Research Service research on biological control of arthropods

During 1999-2001, ARS scientists published over 100 papers on more than 30 species of insect pest and 60 species of predator and parasitoid. These papers address issues crucial to the three strategies of biological control: conservation, augmentation and introduction. Conservation biological control includes both conserving extant populations of natural enemies by using relatively non-toxic pesticides and increasing the abundance of natural enemies in crops by providing or improving refuges for population growth and dispersal into crops. ARS scientists have been very active in determining the effects of pesticides on beneficial arthropods and in studying movement of natural enemies from refuges into crops. Augmentation involves repeated releases of natural enemies in the field, which can be inoculative or inundative. Inoculative releases are used to initiate self-propagating populations at times or in places where they would be slow to colonize. ARS scientists have studied augmentative biological control of a variety of pest insects. The targets are mostly pests in annual crops or other ephemeral habitats, where self-reproducing populations of natural enemies are not sufficiently abundant early enough to keep pest populations in check. ARS research in augmentative biological control centers on methods for rearing large numbers of healthy, effective natural enemies and for releasing them where and when they are needed at a cost less than the value of the reduction in damage to the crop. ARS scientists have researched various aspects of introductions of exotic biological control agents against a diversity of pest insects. The major issues in biological control introductions are accurate identification and adequate systematics of both natural enemies and target pests, exploration for natural enemies, predicting the success of candidates for introduction and the likelihood of non-target impacts, quarantine and rearing methods, and post-introduction evaluation of establishment, control and non-target impacts. ARS scientists have published research on several general issues in biological control. Among the most important are the mechanisms affecting mate- and host-finding and host specificity.     

USDA pest risk assessment of biological control organisms1

Today, as managers of plant pest control programs seek more and more alternatives to chemical pesticides, the demand for biological control organisms in the USA has increased significantly in volume and variety. There is a corresponding increase in the numbers of permit requests for biological control agents from foreign sources. Environmentalists, Federal and State plant regulatory agencies in the USA are concerned over the long-term effects of these ‘beneficials’ on the target hosts, non-target organisms, codependency of flora and fauna, and on the general environment. Within the Animal and Plant Health Inspection Service (APHIS) of USDA, Plant Protection and Quarantine (PPQ) protects US agriculture from the introduction and dispersal of harmful plant pests. It does this with the help of a network of Plant Quarantine Officers. PPQ strongly supports biological control strategies and the importation of more effective agents by accommodating the needs of agribusiness under appropriate safeguards. Although most biological control organisms are not plant pests, certain precautions are in order prior to release since shipments may contain unwanted pests, other contaminants and prohibited plant material.     

Pest Control in Malaysia's Perennial Crops: A Half Century Perspective Tracking the Pathway to Integrated Pest Management

Leaf eating insect outbreaks of unprecedented severity occurred on oil palms and cocoa in what became Malaysia, from the late 1950s to early 1960s. Growers faced two crucial questions, what to do about the attacks, and what caused them. The tropical climate generally continues suitable for phytophagous insects to realise their large increase capacity, a factor emphasised in the stable agroecosystem of perennial tree crops. Parasitic and predatory natural enemy insects are equally favoured and maintain control. It became increasingly evident that the prime cause of outbreak was disruption of this balance by the introduction of broad spectrum, long residual contact insecticides (bslrcs), with various contributory factors. Patchy pesticide residues would continue to eliminate inherently exploratory parasitic and predatory insects, something worsened by uneven initial application. In these conditions, there is a complete overlap of generations of both pests and enemies, with no evolution of synchronised or otherwise coordinated life cycles (‘continuous generation mode’– CGM). In outbreaks the pests tend to be at a similar lifecycle stage (‘discrete generation mode’– DGM), so that at times a high proportion of an enemy population that may be building up cannot find a suitable host stage. Simply stopping application was often enough to end the vicious circle of treatment and reoutbreak, but also, commonly, there was heavy damage in the meantime. Selective application was developed, involving inherent pesticide characteristics or method of use opposite in at least one aspect to bslrc (i.e. narrow spectrum, short residue life, or non-contact). Large areas were treated, e.g., from the air. Infestations mostly disappeared with only one or a few applications. In that era of the 1960s, chemical application compatible with biological control was known as ‘integrated control’. The bslrcs had been introduced to control other regularly occurring pests (‘key’ pests), limited localised build up of the target pests e.g., from climatic fluctuations (‘occasional’ pest), or as a ‘precaution’. Some species only appeared after disruption started (‘potential’ pest). Development of selective chemical control continued to be for key and occasional pests, aiming at effective kill once decided upon. Census monitoring ensured application only when justified economically, with timing to the most vulnerable stage in the pest lifecycle. Among non-chemical approaches, cultural methods include provision of suitable flora in the ground vegetation for food sources for adult parasitic insects. Reasonably dense ground vegetation cover is grown to suppress rhinoceros beetle damage in oil palm replantings. Other possibilities include dissemination of insect diseases, traps and attractants, and resistant plant types. This fitted ‘pest management’ which by the mid-1970s came to encompass selective chemical use, as ‘integrated pest management (IPM)’. There were similar developments in other parts of the world, and in other perennial tree crops, extended also to short term crops (e.g., rice and vegetables). IPM is not an esoteric methodology awaiting ‘complete knowledge’. It can be applied on the basis of principle and existing knowledge for the most reliable economic control, targetted to encompass any aspect, such as toxicology and environmental effects. This revised version was published online in July 2006 with corrections to the Cover Date.     

Agricultural insect hybridization and implications for pest management

Biological invasions, the expansion of agricultural frontiers, and climate change favor encounters of divergent lineages of animals and plants, increasing the likelihood of hybridization. However, hybridization of insect species and its consequences for agroecosystems have not received sufficient attention. Gene exchange between distinct and distant genetic pools can improve the survival and reproduction of insect pests, and threaten beneficial insects in disturbed agricultural environments. Hybridization may be the underlying explanation for the recurrent pest outbreaks and control failures in putative hybrid zones, as suspected for bollworm, corn borer, whiteflies, and stink bugs. Reliable predictions of the types of changes that can be expected in pest insect genomes and fitness, and of their impacts on the fate of species and populations remain elusive. Typical steps in pest management, such as insect identification, pest monitoring, and control are likely affected by gene flow and adaptive introgression mediated by hybridization, and we do not have ways to respond to or mitigate the problem. To address the adverse effects of farming intensification and global trade, we must ensure that current integrated pest management programs incorporate up‐to‐date monitoring and diagnostic tools. The rapid identification of hybrids, quantification of levels of introgression, and in‐depth knowledge of what genes have been transferred may help to explain and predict insect population outbreaks and control failures in the future. © 2019 Society of Chemical Industry     

新型土壤熏蒸剂二甲基二硫研究进展

采用熏蒸剂进行土壤消毒可有效控制设施作物及高附加值作物的土传有害生物,其中熏蒸效果突出的熏蒸剂溴甲烷由于会破坏臭氧层而被禁用,导致土传有害生物熏蒸治理过程中缺乏高效稳定的熏蒸产品。二甲基二硫是一种新型熏蒸剂,对有害线虫具有高活性,可兼治部分土传病原菌及杂草。广谱、安全和高效等优点使其成为最有推广应用前景的溴甲烷替代药剂,或将改善国内杀线虫熏蒸剂缺乏的局面。该文系统综述了国内外关于二甲基二硫对土传有害生物的防控活性、作用机制和降解、散发逃逸、扩散分布及残留等环境行为,以及对土壤养分、微生物及非靶标生物等方面的影响,以期为二甲基二硫的开发及推广应用提供参考。     

Factors in the Success and Failure of Microbial Agents for Control of Migratory Pests

Microbial control agents generally kill insects more slowly than chemical pesticides, and fast-moving migratory pests may not at first sight appear to offer the most promising targets for microbial control. Operators responsible for control may need to have recourse to chemical control agents. Nevertheless, there are many occasions when pests breed and feed outside the crop and a microbial control agent can be used. Similarly, immature stages may cause little damage and early treatment in the crop can avoid damage. Microbial control agents are particularly likely to be favoured if the pest breeds in a conservation area, and if a publicly-accountable agency is responsible for control.Other key points of importance are the IPM context, in particular detection, planning and forecasting of outbreaks and the role of natural enemies.With these points in mind, we identify several locust and grasshopper systems where microbial control is becoming established; additionally, Sunn pest of wheat and Armyworm are identified as promising situations forbreak microbials.     

The role of allelopathy in agricultural pest management

Allelopathy is a naturally occurring ecological phenomenon of interference among organisms that may be employed for managing weeds, insect pests and diseases in field crops. In field crops, allelopathy can be used following rotation, using cover crops, mulching and plant extracts for natural pest management. Application of allelopathic plant extracts can effectively control weeds and insect pests. However, mixtures of allelopathic water extracts are more effective than the application of single-plant extract in this regard. Combined application of allelopathic extract and reduced herbicide dose (up to half the standard dose) give as much weed control as the standard herbicide dose in several field crops. Lower doses of herbicides may help to reduce the development of herbicide resistance in weed ecotypes. Allelopathy thus offers an attractive environmentally friendly alternative to pesticides in agricultural pest management. In this review, application of allelopathy for natural pest management, particularly in small-farm intensive agricultural systems, is discussed.     

蚂蚁在森林害虫管理中的作用

捕食性蚂蚁是森林害虫的重要天敌，与同翅目昆虫有共生现象。人类的活动对蚂蚁资源产生巨大影响。建议保护蚂蚁资源，充分发挥蚂蚁在森林害虫管理中的天敌作用     

试论农业害虫的自然控制

作者根据水稻、棉花、玉米、小麦、油菜、果树和蔬菜等的重要害虫几十年的防治经验，论述了农业害虫自然控制因素的作用和自控措施。这些措施包括作物耐抗性的利用、植物性杀虫剂的利用、昆虫行为和习性的利用、天敌资源的保护利用、农业措施的利用以及农业害虫的综合自控技术。依据可持续农业的发展要求，讨论了在农业害虫的治理中应充分重视和利用一切自然控制因素     

Green peach aphid,Myzus persicae (Hemiptera: Aphididae), reproduction during exposure to sublethal concentrations of imidacloprid and azadirachtin

BACKGROUND: Resurgence of insect pests following insecticide applications is often attributed to natural enemy disturbance, but hormesis could be an alternative or additional mechanism. Green peach aphid, Myzus persicae (Sulzer), is an important insect pest of many crops worldwide that may be exposed to sublethal insecticide concentrations over time. Here, the hypothesis that exposure to low concentrations of imidacloprid and azadirachtin can induce hormetic responses in M. persicae is tested in the laboratory. RESULTS: When insects were exposed to potato leaf discs dipped in sublethal concentrations of insecticide, almost all measured endpoints—adult longevity, F1 production, F1 survival and F2 production—were affected, and a statistically significant (P < 0.05) stimulatory response was recorded for F2 production following exposure to imidacloprid. No other measures for hormesis were statistically significant, but other trends of hormetic response were consistently observed. CONCLUSIONS: Given that variable distribution and degradation of insecticides in the field would result in a wide range of concentrations over time and space, these laboratory experiments suggest that exposure to sublethal concentrations of imidacloprid and azadirachtin could stimulate reproduction in M. persicae. Copyright © 2008 Society of Chemical Industry     

4种药剂及其混配组合对甘薯地下害虫的田间防效

地下害虫是甘薯生产中的重要害虫,近年来其发生程度日趋严重.为有效防治甘薯地下害虫,筛选高效低毒的杀虫剂,使用4种药剂及其混配组合在江西南昌、余江进行了田间药效试验.结果表明,4种药剂及其混配组合防治甘薯地下害虫均有效,其中10％噻虫嗪微囊悬浮剂(15.0 kg/hm2)、30％辛硫磷微囊悬浮剂+10％噻虫嗪微囊悬浮剂(...     

Spiders (Araneae) in the pesticide world: an ecotoxicological review

Being one of the most abundant and species‐rich groups of natural enemies occurring in all agroecosystems, spiders are variably affected by pesticide applications. Here, a review is given of research on spider ecotoxicology. More than 40 species of spiders and almost 130 pesticides (acaricides, insecticides, fungicides and herbicides) have been tested so far in the field or under laboratory conditions. Field studies show that the degree of population reduction following pesticide application is a function of a number of factors inherent to pesticides, crops and spider species (guilds). These studies also revealed indirect effects via habitat and prey disruption. Among laboratory studies, a number of papers have investigated only the direct lethal effect. A meta‐analysis of these data reveals that spiders are mainly affected by acaricides and insecticides, particularly neurotoxic substances. Currently, ecotoxicological research on spiders is focused more on direct sublethal effects on a variety of behavioural traits (locomotion, predation, web‐building, reproduction, development) and physiology. Yet a standardised approach to the evaluation of sublethal effects is lacking. A few studies have provided some evidence for hormesis in spiders. Future research should be more concentrated on sublethal effects and the estimation of long‐term changes in spider populations as a result of pesticide treatment. Copyright © 2012 Society of Chemical Industry