Effects of pirimicarb,buprofezin and pymetrozine on survival,development and reproduction of Coccinella undecimpunctata (Coleoptera: Coccinellidae)

The effects of pirimicarb (a neurotoxin), buprofezin (an insect growth regulator) and pymetrozine (an antifeedant) on Coccinella undecimpunctata were assessed by studying the survival and development of all immature stages and the survival and reproductive performance of adults. Insecticides were sprayed at doses recommended by the manufacturers for the control of aphids and/or whiteflies. None of the three insecticides had a significant effect on the survival of C. undecimpunctata eggs. When sprayed on larvae, buprofezin significantly reduced survival to adulthood to <33%, compared to >45% for the control and other insecticide treatments. Rates of adult survival, fecundity, and fertility, and the percentage of egg hatch, were not significantly different between control and insecticide treatments. Thus, larval stages were more susceptible to insecticides than were adults. In general, pirimicarb and pymetrozine had no adverse effects on immature or adult stages of C. undecimpunctata, and hence are suitable for IPM of sucking pests.     

SAR studies directed toward the pyridine moiety of the sap-feeding insecticide sulfoxaflor (Isoclast™ active)

Sap-feeding insect pests constitute a major insect pest complex that includes a range of aphids, whiteflies, planthoppers and other insect species. Sulfoxaflor (Isoclast™ active), a new sulfoximine class insecticide, targets sap-feeding insect pests including those resistant to many other classes of insecticides. A structure activity relationship (SAR) investigation of the sulfoximine insecticides revealed the importance of a 3-pyridyl ring and a methyl substituent on the methylene bridge linking the pyridine and the sulfoximine moiety to achieving strong Myzus persicae activity. A more in depth QSAR investigation of pyridine ring substituents revealed a strong correlation with the calculated log octanol/water partition coefficient (S log P). Model development resulted in a highly predictive model for a set of 18 sulfoximines including sulfoxaflor. The model is consistent with and helps explain the highly optimized pyridine substitution pattern for sulfoxaflor.     

昆虫内共生菌沃尔巴克氏体抗病毒研究进展

植物病毒病是危害我国蔬菜生产的第一大病害,而烟粉虱Bemisia tabaci Gennadius、蓟马和蚜虫等小型昆虫是蔬菜病毒病的主要传播媒介.虫传病毒病害的防控策略复杂且难度大,目前生产上主要依赖化学农药防治介体昆虫,预防与控制蔬菜病毒病.种植户化学杀虫药剂的不合理使用、甚至滥用,导致媒介昆虫抗药性、杀虫剂污染与...     

Resistance of insect pests to neonicotinoid insecticides: current status and future prospects

The first neonicotinoid insecticide introduced to the market was imidacloprid in 1991 followed by several others belonging to the same chemical class and with the same mode of action. The development of neonicotinoid insecticides has provided growers with invaluable new tools for managing some of the world's most destructive crop pests, primarily those of the order Hemiptera (aphids, whiteflies, and planthoppers) and Coleoptera (beetles), including species with a long history of resistance to earlier-used products. To date, neonicotinoids have proved relatively resilient to the development of resistance, especially when considering aphids such as Myzus persicae and Phorodon humuli. Although the susceptibility of M. persicae may vary up to 20-fold between populations, this does not appear to compromise the field performance of neonicotinoids. Stronger resistance has been confirmed in some populations of the whitefly, Bemisia tabaci, and the Colorado potato beetle, Leptinotarsa decemlineata. Resistance in B- and Q-type B. tabaci appears to be linked to enhanced oxidative detoxification of neonicotinoids due to overexpression of monooxygenases. No evidence for target-site resistance has been found in whiteflies, whereas the possibility of target-site resistance in L. decemlineata is being investigated further. Strategies to combat neonicotinoid resistance must take account of the cross-resistance characteristics of these mechanisms, the ecology of target pests on different host plants, and the implications of increasing diversification of the neonicotinoid market due to a continuing introduction of new molecules.     

The role of olfaction in aphid host location

Aphids are major economic pests of many of the worlds' crops, causing damage directly by feeding and by acting as vectors for plant viruses. By understanding how aphids locate their host plants, it may become possible to develop new means of controlling populations by taking advantage of these natural host location/nonhost avoidance behaviours. Aphids have also become important model organisms in the study of insect–plant interactions and an improved understanding of host location in aphids could yield insights into the behaviour and ecology of other insect orders. The use of olfaction by host‐seeking aphids is well documented and, in recent years, considerable information has been gained on how volatiles can encode host identity and suitability, as well as the specific behaviours they elicit from aphids. The purpose of this review is to highlight the major findings on how aphids respond behaviourally to volatile compounds and how they can use them to locate their host plants and avoid unsuitable hosts.     

Insect growth regulatory and larvicidal activity of chalcones against Aedes albopictus

Widespread use of chemical insecticides has resulted in development of insect resistance and natural products with biological activities could become an attractive alternative to control insect pests. In order to find more effective insecticides for controlling mosquito, various mosquitocidal compounds are studied. Recently, juvenile hormone antagonists (JHANs) have been found to be to safe and effective insecticides for control of mosquito. In order to identify novel insecticidal compounds with JHAN activity, several chalcones were surveyed on their JHAN activities and larvicidal activities against Aedes albopictus larvae. Among them, 2′‐hydroxychalcone and cardamonin showed high levels of JHAN and mosquito larvicidal activities. These results suggested that chalcones with JHAN activity could be useful for control of mosquito larvae.     

Insect reactions to light and its applications to pest management

Insects are able to see ultraviolet (UV) radiation. Nocturnal insects are often attracted to light sources that emit large amounts of UV radiation, and devices that exploit this behavior, such as light traps for forecasting pest outbreaks, and electric insect killers, have been developed. Some diurnal species are attracted to yellow; yellow pan traps are used for conducting surveys for pest outbreaks and yellow sticky plates are used for pest control. Lamps that give off yellow illumination have been used effectively to control the activity of nocturnal moths and thus reduce damage to fruit, vegetables, and flowers. Covering cultivation facilities with film that filters out near-UV radiation reduces the invasion of pests such as whiteflies and thrips into the facilities, thus reducing damage. Reflective material placed on cultivated land can control the approach of flying insects such as aphids. Future development and use of new light sources such as light-emitting diodes is anticipated for promoting integrated pest management.     

Current status and future perspectives on natural enemies for pest control in Taiwan

ABSTRACT

In Taiwan, the agricultural policy, ‘Reduce the consumption of pesticide to half in the next 10 years’, was launched in 2017. Pesticide application, which results in contamination of food by chemical residues, pest resistance, and other adverse ecological effects, is a growing public and environmental concern. Pest control by natural predators is, thus, the best alternative. Biological control methods implemented based on insights obtained from studies on pest behaviour, rearing, and various crop management modes, increase the possibility of controlling pests in modern organic agricultural systems. More than a decade has passed since the first introduction of a predatory insect in Taiwan for pest control (in the 1990s). Predatory and parasitic natural enemies, including lacewing, predatory stink bugs, Orius, and parasitic wasps, were initially used for controlling thrips, aphids, spider mites, whiteflies, and lepidopteran pests. At present, there exists a wide range of integrated pest management (IPM) methods incorporating other non-chemical, biological, and agricultural methods. However, recently, there has been an increase in research and development on the utilisation of natural enemies of insects and the associated food safety issues. Mass production and release, storage, and handling techniques of insect predators and parasitoids have been successful in recent years. The final goal of present day research is to develop natural enemy products and provide an IPM-based model to farmers for using natural enemies in agricultural production systems, thereby reducing pesticide application and ensuring food security.     

Evaluation of insecticidal properties of botanicals for sustainable management of sucking pests of horticultural crops

Aphids, thrips, whiteflies, mealy bugs and mites could cause significant yield losses in horticultural crops. Many synthetic chemicals highly hazardous to non-target organisms and the environment are in use in their management. Botanicals are ideal for safe sustainable pest management by keeping synthetic chemical use at a minimum. We studied the insecticidal properties of three botanicals viz., Annona squamosa, Ricinus communis and Sapindus mukorossi seed extracts against sucking pests viz., aphids (Aphis gossypii and Aphis craccivora) on okra (Abelmoschus esculentus) and bittergourd (Momordica charantia), thrips (Scirtothrips dorsalis) on chilli (Capsicum frutescens), whiteflies (Bemisia tabaci) on eggplant (Solanum melongena), mealy bugs (Maconellicoccus hirsutus) on betel vine (Piper betle) and mites (Tetranychus urticae) on eggplant (Solanum melongena) under laboratory conditions. The bioassay showed that A. squamosa seed extract has potent insecticidal properties on all sucking pests, except T. urticae. Though S. mukorossi seed extract exhibited no insecticidal property, had a significant acaricidal property. A. squamosa and S. mukorossi seed extracts will therefore be additional botanicals for use in organic farming for managing the sucking pests effectively.     

Expanding radiation quarantine treatments beyond fruit flies

1 The potential of ionizing radiation as a disinfestation treatment for insects other than tephritid fruit flies is discussed. Radiation quarantine treatments are unique in that insects are not killed immediately but rendered sterile or incapable of completing development. 2 The most tolerant insect stage to radiation is that which is most developed. Female insects, but not always mites, are sterilized with equal or lower doses than males. 3 Insects irradiated with sterilizing doses usually have shorter longevities than non‐irradiated ones. Low oxygen conditions often increase tolerance to radiation. 4 Insects in diapause are not more tolerant of radiation than non‐diapausing ones. 5 Some pests of several groups, such as aphids, whiteflies, weevils, scarab beetles, and fruit flies, may be controlled with doses ≤ 100 Gy. Some lepidopterous pests and most mites require about 300 Gy. Stored product moths may require as much as 1 kGy to sterilize, and nematodes could need > 4 kGy. 6 Even though application of irradiation to pallet‐loads of produce could mean that up to three times the minimum required dose is applied to the perimeter of the pallet, many fresh commodities tolerate doses required for quarantine security against many quarantined pests. Irradiation is arguably the most widely applicable quarantine treatment from the standpoint of commodity quality.     

Alyssum flowers promote biological control of collard pests

Collard greens Brassica oleracea (L.) are often attacked by various pests including whiteflies, aphids and diamondback moth. Hitherto, the main method used to manage these pests in Brazil has been the application of a limited number of registered insecticides. The search for more sustainable pest management strategies is therefore warranted. In this context, the conservation biological control stands out as an appealing alternative. Conservation biological control is achieved, at least in part, by strip-cultivating and/or conserving flowering plants within the agroecosystem. The present study investigates how alyssum flowers Lobularia maritima (L.) could contribute to the attraction of natural enemies and to the management of collard pests. Two field experiments were conducted in different years. Each experiment consisted of two treatments and three replicates, which were set up in a completely randomized design. The treatments were (1) collards alone, and (2) collards + alyssum. We evaluated weekly the population density of natural enemies and pests on both treatments. The results show that the alyssum flowers attractiveness contributed to increase the abundance of generalist predators during both experiments, which in turn translated into a significant reduction of collards pests, especially aphids. Some of the main predators attracted/harbored by alyssum flowers were spiders, coccinellids, syrphids and Orius sp. Finally, strip intercropping alyssum with collards can be an important strategy to manage brassica pests and cope with the limited availability of insecticides registered for this vegetable crop.     

Advances in Transgenic Research for Insect Resistance in Sugarcane

The first phase of transgenic research in sugarcane concentrated on the development and evaluation of transgenic lines transformed for resistance to biotic stresses, particularly diseases and insect pests. Sugarcane is attacked by a range of insects including tissue borers, sucking pests and canegrubs. Losses due to these pests are estimated to be around 10%. Although chemical control and integrated pest management are regularly practiced for the control of insect pests, success is often limited due to practical difficulties. The genetic complexity of sugarcane coupled with the non-availability of resistance genes in the germplasm has made conventional breeding for insect resistance difficult. In this context, transgenic technology has become a handy tool for imparting insect resistance to an elite variety which is otherwise superior for most other agronomic traits. A number of transgenic sugarcane lines have been developed with genes expressing Cry proteins, proteinase inhibitors or lectins resistant to borers, sucking insects or grubs. While commercializing transgenic lines, issues such as higher and stable transgene expression, preparedness for resistance management and non-target effects need to be addressed. To manage the constant threat of resistance development in target insects, it is imperative to deploy field-level strategies taking clues from other crops coupled with the search for new potent replacement molecules for transformation.     

Spatial Distribution and Site-Specific Spraying of Main Sucking Pests of Elm Trees

Elm trees are important landscape trees and sucking insects weaken the elm trees and produce large amounts of honeydew. The main objectives of this study were to identify main honeydew-producing pests of elm trees and do site-specific spraying against these pests. To map the spatial distribution of the sucking pests in the large scale, the study area was divided into 40?×?40 m grids and one tree was chosen randomly from each grid (a total of 55 trees). These trees were sampled twice a year in 2011 and 2012. Each sample was a 30-cm branch terminal. Eight samples were taken from each tree in four cardinal directions and two canopy levels. The number of sucking insects and leaves of each sample were counted and recorded. Spatial analysis of the data was carried out using geostatistics. Kriging was used for producing prediction maps. Insecticide application was restricted to the regions with populations higher than threshold. To identify within-tree distribution of the honeydew-producing pests, six and four elm trees were chosen in 2011 and 2012 respectively, and sampled weekly. These trees were sampled as described previously. European elm scale (EES), Gossyparia spuria (Modeer) and two species of aphids were the dominant honeydew-producing pests. The results revealed that the effects of direction, canopy level and their interactions on insect populations were not statistically significant (P?<?0.05). Site-specific spraying decreased the amount of insecticides used by ca. 20%, while satisfactory control of the sucking pests and honeydew excretion was obtained. Considering the environmental and economic benefits of site-specific spraying, it is worth doing more complementary works in this area.     

A review of <Emphasis Type="Italic">Piper</Emphasis> spp. (Piperaceae) phytochemistry,insecticidal activity and mode of action

The tropical plant family Piperaceae has provided many past and present civilizations with a source of diverse medicines and food grade spice. The secondary plant compounds that produce these desired qualities function also as chemical defenses for many species in the genus Piper. The compounds with the greatest insecticidal activity are the piperamides. Many studies have shown the effectiveness of Piper spp. extracts for the control of stored products pests and recently studies from our laboratory group have tested the extracts of Piper. nigrum, P. guineense and P. tuberculatum against insect pests of the home and garden. These results and those from investigations that examined the biochemical and molecular modes of action of the piperamides singly or in combination will be the focus of this review. The conclusions of our current work with Piperaceae are that Piper extracts offer a unique and useful source of biopesticide material for controlling small-scale insect out-breaks and reducing the likelihood of resistance development when applied as a synergist with other botanical insecticides such as pyrethrum.     

Effects of kaolin particle film on Myzus persicae (Hemiptera: Aphididae) behaviour and performance

The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreated (or water solvent-treated) leaf areas, both adults and nymphs exhibited a significant preference for non-kaolin-treated host-plant material. Rejection of kaolin-treated plant material occurred very rapidly (within 20 min) and this behavioural effect may be related to the efficacy of kaolin in controlling aphids under field conditions.     

Can microbial-based insecticides replace chemical pesticides in agricultural production?

Extensive use of chemical insecticides to control insect pests in agriculture has improved yields and production of high-quality food products. However, chemical insecticides have been shown to be harmful also to beneficial insects and many other organisms like vertebrates. Thus, there is a need to replace those chemical insecticides by other control methods in order to protect the environment. Insect pest pathogens, like bacteria, viruses or fungi, are interesting alternatives for production of microbial-based insecticides to replace the use of chemical products in agriculture. Organic farming, which does not use chemical pesticides for pest control, relies on integrated pest management techniques and in the use of microbial-based insecticides for pest control. Microbial-based insecticides require precise formulation and extensive monitoring of insect pests, since they are highly specific for certain insect pests and in general are more effective for larval young instars. Here, we analyse the possibility of using microbial-based insecticides to replace chemical pesticides in agricultural production.     

植物-昆虫间的化学通讯及其行为控制

在植物与昆虫间的化学通讯中植物气味物质起着决定性的作用,它调控着昆虫的多种行为,诸如引诱昆虫趋向寄主植物,刺激昆虫取食,引导昆虫选择产卵场所,进行传粉和防御昆虫等。有些植物则当受到食植性昆虫危害时会释出一些引诱害虫天敌的化学信号。这些化学信号是一些挥发性萜类混合物,天敌昆虫就以此来区分受害和未受害植株。尽管目前在害虫综合治理中,昆虫信息素的应用越来越显得比天然植物气味源更受重视,但是必须指出的是,昆虫信息化合物首次成功地使用于植物保护的却是天然植物气味源。在利用植物气味源作害虫测报和防治中,近年来一种简单价廉的粘胶诱捕器己成为多种害虫的标准测报工具。在害虫综合治理中利用植物气味源的技术显然是具有不可估量的潜力。文中提出了利用基因工程技术来改造植物,使植物能释放特定的驱避剂或其它控制昆虫行为的特殊气味物质的新概念。     

Biological control of cotton pests in China

Cotton is one of the most economically important crops in China, while insect pest damage is the major restriction factor for cotton production. The strategy of integrated pest management (IPM), in which biological control plays an important role, has been widely applied. Nearly 500 species of natural enemies have been reported in cotton systems in China, but few species have been examined closely. Seventy-six species, belonging to 53 genera, of major arthropod predators and parasitoids of lepidoptera pests, and 46 species, belonging to 29 genera, of natural enemies of sucking pests have been described. In addition, microsporidia, fungi, bacteria and viruses are also important natural enemies of cotton pests. Trichogramma spp., Microplitis mediator, Amblyseius cucumeris, Bacillus thuringiensis and Helicoverpa armigera nuclear polyhedrosis virus (HaNPV) have been mass reared or commercially produced and used in China. IPM strategies for cotton pests comprising of cultural, biological, physical and chemical controls have been developed and implemented in the Yellow River Region (YRR), Changjiang River Region (CRR) and Northwestern Region (NR) of China over the past several decades. In recent years, Bt cotton has been widely planted for selectively combating cotton bollworm, H. armigera, pink bollworm, Pectinophora gossypiella, and other lepidopteran pest species. As a result of reduced insecticide sprays, increased abundance of natural enemies in Bt cotton fields efficiently prevents outbreaks of other pests such as cotton aphids. In contrast, populations of mirid plant bugs have increased dramatically due to a reduction in the number of foliar insecticide applications for control of the bollworms in Bt cotton, and now pose a key problem in cotton production. In response to this new pest issue in cotton production, control strategies including biological control measures are being developed in China.     

Strain improvement of fungal insecticides for controlling insect pests and vector-borne diseases

Insect pathogenic fungi play an important natural role in controlling insect pests. However, few have been successfully commercialized due to low virulence and sensitivity to abiotic stresses that produce inconsistent results in field applications. These limitations are inherent in most naturally occurring biological control agents but development of recombinant DNA techniques has made it possible to significantly improve the insecticidal efficacy of fungi and their tolerance to adverse conditions, including UV. These advances have been achieved by combining new knowledge derived from basic studies of the molecular biology of these pathogens, technical developments that enable very precise regulation of gene expression, and genes encoding insecticidal proteins from other organisms, particularly spiders and scorpions. Recent coverage of genomes is helping determine the identity, origin, and evolution of traits needed for diverse lifestyles and host switching. In future, such knowledge combined with the precision and malleability of molecular techniques will allow design of multiple pathogens with different strategies and host ranges to be used for different ecosystems, and that will avoid the possibility of the host developing resistance. With increasing public concern over the continued use of synthetic chemical insecticides, these new types of biological insecticides offer a range of environmental-friendly options for cost-effective control of insect pests.