Recent trends in global insecticide use for disease vector control and potential implications for resistance management.

Insecticides have played a major role in the prevention, control, and elimination of vector-borne diseases, but insecticide resistance threatens the efficacy of available vector control tools. A global survey was conducted to investigate vector control insecticide use from 2010 to 2019. Out of 140 countries selected as sample for the study, 87 countries responded. Also, data on ex-factory deliveries of insecticide-treated nets (ITNs) were analyzed. Insecticide operational use was highest for control of malaria, followed by dengue, leishmaniasis and Chagas disease. Vector control relied on few insecticide classes with pyrethroids the most used overall. Results indicated that IRS programs have been slow to react to detection of pyrethroid resistance, while proactive resistance management using insecticides with unrelated modes of action was generally weak. The intensive use of recently introduced insecticide products raised concern about product stewardship regarding the preservation of insecticide susceptibility in vector populations. Resistance management was weakest for control of dengue, leishmaniasis or Chagas disease. Therefore, it will be vital that vector control programs coordinate on insecticide procurement, planning, implementation, resistance monitoring, and capacity building. Moreover, increased consideration should be given to alternative vector control tools that prevent the development of insecticide resistance.

Perspectives on the Changing Landscape of Epizootic Hemorrhagic Disease Virus Control.

Epizootic hemorrhagic disease (EHD) is an insect-transmitted viral disease of wild and domestic ruminants. It was first described following a 1955 epizootic in North American white-tailed deer (Odocoileus virginianus), a species which is highly susceptible to the causative agent of EHD, epizootic hemorrhagic disease virus (EHDV). EHDV has been detected globally across tropical and temperate regions, largely corresponding to the presence of Culicoides spp. biting midges which transmit the virus between ruminant hosts. It regularly causes high morbidity and mortality in wild and captive deer populations in endemic areas during epizootics. Although cattle historically have been less susceptible to EHDV, reports of clinical disease in cattle have increased in the past two decades. There is a pressing need to identify new methods to prevent and mitigate outbreaks and reduce the considerable impacts of EHDV on livestock and wildlife. This review discusses recent research advancements towards the control of EHDV, including the development of new investigative tools and progress in basic and applied research focused on virus detection, disease mitigation, and vector control. The potential impacts and implications of these advancements on EHD management are also discussed.

Genetic engineering of crops for insect resistance: An overview.

Phytophagous insect incidence is a serious threat for reduction of crop productivity globally. There is an estimation of one fourth of crop is being destroyed by insects annually. Indeed, the development of insect-resistant crops is a great milestone in agriculture to increase crop yield and reduce pesticide dependency. Genetic engineering facilitates development of insect resistant crops by expressing bacterial δ-endotoxins and vegetative insecticidal proteins and other plant genes like lectins, protease inhibitors, etc. In addition, RNA interference and genome editing through CRISPR Cas9 also provides new solutions for the development of insect-resistant crops. The resultant genetically modified crops showed resistance against lepidopteran, dipteran, homopteran and coleopteran insects. The insect-resistant crops have made a significant economic impact worldwide in terms of higher yield and low pesticide usage. In this review, we focus on different strategies for developing transgenics against insect pest control by expressing different insecticidal proteins in crops.

Botanical Insecticides in the Twenty-First Century-Fulfilling Their Promise?

Academic interest in plant natural products with insecticidal properties has continued to grow in the past 20 years, while commercialization of new botanical insecticides and market expansion of existing botanicals has lagged considerably behind. Insecticides based on pyrethrum and neem (azadirachtin) continue to be standard bearers in this class of pesticides, but globally, their increased presence is largely a consequence of introduction into new jurisdictions. Insecticides based on plant essential oils are just beginning to emerge as useful plant protectants. Some countries (such as Turkey, Uruguay, the United Arab Emirates, and Australia) have relaxed regulatory requirements for specific plant extracts and oils, while in North America and the European Union, stricter requirements have slowed progress toward commercialization of new products. Botanicals are likely to remain niche products in many agricultural regions and may have the greatest impact in developing countries in tropical regions where the source plants are readily available and conventional products are both expensive and dangerous to users.

Microbial biopesticides for control of invertebrates: Progress from New Zealand.

Biopesticides are needed for control of endemic and invasive pests impacting New Zealand's primary sectors including pests that are emerging as a result of climate change and farming intensification. Products developed in New Zealand are usually based on endemic strains of microorganisms, including new species/strains with novel modes of action. For example, Invade and BioShield were developed using endemic strains of the bacterium Serratia entomophila, for use in New Zealand only. To date, most of these home-grown products have either struggled for market share or have remained in small niche markets. However, the number of products registered for use has been steadily increasing in response to consumer demand. Factors limiting past use of biopesticides in New Zealand include market size, registration costs and limited efficacy over a range of climatic zones. Many promising new agents are currently under development as biopesticides with international applications and the launch of several new start-up companies suggests a brighter future for biopesticide use in New Zealand.

Microbial control of phytophagous invertebrate pests in South Africa: Current status and future prospects.

Invertebrate pests pose a significant threat to food security on the African continent. In response, South Africa has become one of the largest importers of chemical pesticides in sub-Saharan Africa, with several hundred active ingredients registered. To address the over-reliance on such chemicals, the South African Department of Agriculture, Forestry and Fisheries (DAFF) has eliminated or restricted several pesticides since the late 1970s. The recent launch of the South African National Bio-Economy Strategy and establishment of the South African Bioproducts Organisation (SABO), together with new guidelines for registration of biopesticides in 2015, also support this endeavour. Concurrently, entomopathogen-related research and bioproduct development has increased over the past decade. Currently, 31 products (seven manufactured locally) are registered under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Commercially important microbes include Beauveria bassiana (Cordycipitaceae), Metarhizium anisopliae (Clavicipitaceae), Cydia pomonella granulovirus, Cryptophlebia leucotreta granulovirus, Helicoverpa armigera nucleopolyhedrovirus (Baculoviridae) and Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai (Bacillaceae). Both parasitic and entomopathogenic nematodes (EPNs) show potential for development as bioinsecticides with one commercial EPN product, based on Heterorhabditis bacteriophora (Heterorhabditidae), registered under the Act. Rapid scientific progression, supported by a favourable legislative environment, should facilitate further advances in microbial control of phytophagous invertebrate pests in South Africa.

Current status and perspectives of fungal entomopathogens used for microbial control of arthropod pests in Brazil.

Entomopathogenic fungi play a central role in Brazil's biopesticide market. Approximately 50% of registered microbial biopesticides comprise mycoinsecticides and/or mycoacaricides consisting of hypocrealean fungi, with most based on Metarhizium anisopliae sensu stricto (s. str.) and Beauveria bassiana s. str. These fungi are mainly used to control spittlebugs in sugarcane fields and whiteflies in row crops, respectively, with annual applications surpassing three million hectares. Research also emphasizes the potential of fungal entomopathogens to manage arthropod vectors of human diseases. Most registered fungal formulations comprise wettable powders or technical (non-formulated) products, with relatively few new developments in formulation technology. Despite the large area treated with mycoinsecticides (i.e., approx. 2 million ha of sugarcane treated with M. anisopliae and 1.5 million ha of soybean treated with B. bassiana), their market share remains small compared with the chemical insecticide market. Nevertheless, several major agricultural companies are investing in fungus-based products with the aim at achieving more sustainable IPM programs for major pests in both organic and conventional crops. Government and private research groups are pursuing innovative technologies for mass production, formulation, product stability and quality control, which will support cost-effective commercial mycoinsecticides. Here, we summarize the status of mycoinsecticides currently available in Brazil and discuss future prospects.

Microbial insecticides in Iran: History, current status, challenges and perspective.

Biological control programs with arthropods have been in practice in Iran since the 1930s. However, development and registration of microbial biopesticides is much more recent. Currently, about 15 biopesticide products are registered or pending registration for commercial use on various crops. Products based on Bacillus thuringiensis subsp. kurstaki are most widely sold for lepidopteran pest control, followed by B. thuringiensis subsp. isralensis against dipteran pests in vector control programs. Additionally, mycoinsecticides based on Lecanicillium lecanii and Beauveria bassiana, against various arthropod pests, and a mycofungicide based on Trichoderma harzianum for controlling soilborne diseases are also registered. In Iran, the national Plant Protection Organization (PPO) manages regulation of microbial pesticides and the Pesticide Supervision Board within the PPO oversees registration of all pesticides. Currently, two Iranian companies produce microbial pesticides and two more companies are approved to start production in the near future. We review the history of microbial control of arthropod pests in Iran with examples of sustainable agricultural practices, the current status of the market and registration procedures for microbial pesticides, along with the challenges and opportunities for the advancement of microbial control in Iran.

Recent Trends in Wasp Nest Removal and Hymenoptera Stings in South Korea.

To better understand the impact of social wasps on the health of people in South Korea, we analyzed requests to emergency services call centers for the removal of social wasp nests and the effect of Hymenoptera stings on human health between 2010 and 2014. There were 483,233 calls requesting removal of wasp nests and Hymenoptera stings caused 78,860 injuries and 49 deaths. The strong relationships between both the number of emergency calls and injuries, and urban density reflect the sensitivity of densely populated areas to potential threats from wasp and the increased awareness of the wasp nest removal service communicated by public education programs. We found that the removed nests belonged to 17 species of social wasp, with Polistes rothneyi koreanus Vecht and Vespa velutina nigrithorax du Buysson being the most prevalent. Problems associated with the invasive V. v. nigrithorax increased as the species became more widely distributed across the country and more abundant in urban areas. Increases in the incidence of sting injuries among males aged 40-69 between July and September were likely due to increased exposure during outdoor activities involving less-fit adults. In total, 1.5% of victims required hospitalization, of which 98.5% were treated as outpatients. Total medical costs associated with wasp stings over the 5-yr period were approximately 3.2 million USD. Although most wasp sting-related injuries were minor, some were serious, including fatalities, and were probably attributable to lack of education on wasp attack behavior.

Microbial biopesticides for insect pest management in India: Current status and future prospects.

The biopesticide industry in India is undergoing rapid change, reflecting increased global trade in agricultural commodities, a changing regulatory environment and evolving consumer preferences. Currently biopesticides comprise ≈ 5% of the Indian pesticide market, with at least 15 microbial species and 970 microbial formulations registered through the Central Insecticides Board and Registration Committee (CIBRC). As of 2017, over 200 products based on entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Metarhizium anisopliae s.l., Lecanicillium lecanii and Hirsutella thompsonii) and nematicidal fungi (Purpureocillium lilacinum and Pochonia chlamydosporia) are registered for use against various arthropods and plant parasitic nematodes. Regarding bacteria, over 30 products based on Bacillus thuringiensis (Bt) subsp. kurstaki are registered against bollworms, loopers and other lepidopterans, while 12 based on Bt subsp. israelensis and three with Bt subsp. sphaericus have been used against mosquitoes. Two viruses are registered, namely Helicoverpa armigera nucleopolyhedrovirus (22 products) and Spodoptera litura nucleopolyhedrovirus (5 products) for use against bollworms and armyworms. Four entomopathogenic nematode species are sold in Indian market. These include long-lasting wettable powder formulations of Heterorhabditis indica developed by the ICAR-National Bureau of Agricultural Insect Resources, Bengaluru which have been distributed on a large scale to control white grubs and other sugarcane pests. Biopesticide research on the subcontinent is at a relatively early stage, but evolving rapidly, and focusing on indigenous entomopathogens. Despite onerous regulation, quality-control issues and limited large-scale production facilities, investment in domestic fermentation technologies, improved delivery systems, and promotion of biological control through private and public initiative will increase the share of microbial biopesticides in the country.

The Management of Insect Pests in Australian Cotton: An Evolving Story.

The Australian cotton industry progressively embraced integrated pest management (IPM) to alleviate escalating insecticide resistance issues. A systems IPM approach was used with core principles that were built around pest ecology/biology and insecticide resistance management; together, these were integrated into a flexible, year-round approach that facilitated easy incorporation of new science, strategies, and pests. The approach emphasized both strategic and tactical elements to reduce pest abundance and rationalize decisions about pest control, with insecticides as a last resort. Industry involvement in developing the approach was vital to embedding IPM within the farming system. Adoption of IPM was facilitated by the introduction of Bt cotton, availability of selective insecticides, economic validation, and an industry-wide extension campaign. Surveys indicate IPM is now embedded in industry, confirming the effectiveness of an industry-led, backed-by-science approach. The amount of insecticide active ingredient applied per hectare against pests has also declined dramatically. Though challenges remain, pest management has transitioned from reactively attempting to eradicate pests from fields to proactively managing them year-round, considering the farm within the wider landscape.

Ecology, Worldwide Spread, and Management of the Invasive South American Tomato Pinworm, Tuta absoluta: Past, Present, and Future.

The South American tomato pinworm, Tuta absoluta (Meyrick), is native to the western Neotropics. After invading Spain in 2006, it spread rapidly throughout Afro-Eurasia and has become a major threat to world tomato production. Integrated pest management (IPM) strategies have been developed, but widespread insecticide use has caused selection for insecticide resistance as well as undesirable effects on key beneficial arthropods. Augmentation and conservation biological control relying on omnivorous mirid predators has proved successful for management of T. absoluta, where implementation is dependent on abiotic, biotic (e.g., alternative prey), and anthropogenic factors (e.g., pesticides). Research has been carried out on larval parasitoids, showing potential for further development of sustainable control. The development of resistant tomato varieties is ongoing, but they are not commercially available yet. Knowledge gaps remain to be filled to optimize IPM packages on tomato crops and to help prevent further spread worldwide.

Recombinant entomopathogenic agents: a review of biotechnological approaches to pest insect control.

Although the use of chemical pesticides has decreased in recent years, it is still a common method of pest control. However, chemical use leads to challenging problems. The harm caused by these chemicals and the length of time that they will remain in the environment is of great concern to the future and safety of humans. Therefore, developing new pest control agents that are safer and environmentally compatible, as well as assuring their widespread use is important. Entomopathogenic agents are microorganisms that play an important role in the biological control of pest insects and are eco-friendly alternatives to chemical control. They consist of viruses (non-cellular organisms), bacteria (prokaryotic organisms), fungi and protists (eukaryotic organisms), and nematodes (multicellular organisms). Genetic modification (recombinant technology) provides potential new methods for developing entomopathogens to manage pests. In this review, we focus on the important roles of recombinant entomopathogens in terms of pest insect control, placing them into perspective with other views to discuss, examine and evaluate the use of entomopathogenic agents in biological control.

Harnessing Integrated Vector Management for Enhanced Disease Prevention.

The increasing global threat of emerging and re-emerging vector-borne diseases (VBDs) poses a serious health problem. The World Health Organization (WHO) recommends integrated vector management (IVM) strategy for combating VBD transmission. An IVM approach requires entomological knowledge, technical and infrastructure capacity, and systems facilitating stakeholder collaboration. In sub-Saharan Africa, successful operational IVM experience comes from relatively few countries. This article provides an update on the extent to which IVM is official national policy, the degree of IVM implementation, the level of compliance with WHO guidelines, and concordance in the understanding of IVM, and it assesses the operational impact of IVM. The future outlook encompasses rational and sustainable use of effective vector control tools and inherent improved return for investment for disease vector control.

Past and Ongoing Tsetse and Animal Trypanosomiasis Control Operations in Five African Countries: A Systematic Review.

BACKGROUND: Control operations targeting Animal African Trypanosomiasis and its primary vector, the tsetse, were covering approximately 128,000 km2 of Africa in 2001, which is a mere 1.3% of the tsetse infested area. Although extensive trypanosomiasis and tsetse (T&T) control operations have been running since the beginning of the 20th century, Animal African Trypanosomiasis is still a major constraint of livestock production in sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS: We performed a systematic review of the existing literature describing T&T control programmes conducted in a selection of five African countries, namely Burkina Faso, Cameroon, Ethiopia, Uganda and Zambia, between 1980 and 2015. Sixty-eight documents were eventually selected from those identified by the database search. This was supplemented with information gathered through semi-structured interviews conducted with twelve key informants recruited in the study countries and selected based on their experience and knowledge of T&T control. The combined information from these two sources was used to describe the inputs, processes and outcomes from 23 major T&T control programmes implemented in the study countries. Although there were some data gaps, involvement of the target communities and sustainability of the control activities were identified as the two main issues faced by these programmes. Further, there was a lack of evaluation of these control programmes, as well as a lack of a standardised methodology to conduct such evaluations. CONCLUSIONS/SIGNIFICANCE: Past experiences demonstrated that coordinated and sustained control activities require careful planning, and evidence of successes, failures and setbacks from past control programmes represent a mine of information. As there is a lack of evaluation of these programmes, these data have not been fully exploited for the design, analyses and justification of future control programmes.

Advances in control techniques for Culicoides and future prospects.

In most instances, vaccination is accepted to be the most effective method of preventing Culicoides-borne arbovirus transmission, as it has proven to be successful in large-scale campaigns. Under certain scenarios, however, vaccines require time to be developed and deployed or are not used due to financial, logistical or trade constraints. In the absence of vaccines, animal movement restrictions and techniques to reduce either the number of Culicoides biting livestock or their subsequent survival are the only responses available to prevent or reduce arbovirus transmission and spread. This review evaluates the progress made during the past 10 years in the development of Culicoides control techniques for this purpose and assesses their potential impact in reducing arbovirus transmission. In addition, the future prospects and challenges facing Culicoides control are examined and suggestions are made as to research directions and opportunities.

The Anopheles maculipennis complex (Diptera: Culicidae) in Germany: an update following recent monitoring activities.

The Anopheles maculipennis complex comprises several sibling species including major vectors of malaria parasites of historic Europe. In present-day Europe, these species are probably more relevant with regard to transmission of pathogens other than plasmodia, such as viruses and dirofilariae. Distribution data facilitating risk assessments and modelling of An. maculipennis complex-borne diseases, however, are generally outdated. In Germany, the occurrence and geographic distribution of the complex species have recently been updated within the framework of a national monitoring programme. In addition to the known indigenous species An. maculipennis, Anopheles messeae and Anopheles atroparvus, the newly described sibling species Anopheles daciae was demonstrated. Distribution maps of these species based on the data collected from 2011 to 2014 are presented, whilst ecological characteristics and vector roles are presented and discussed.

Evaluation of light-emitting diodes as attractant for sandflies (Diptera: Psychodidae: Phlebotominae) in northeastern Brazil.

Hoover Pugedo light traps were modified for use with green and blue-light-emitting diodes to trap phlebotomine sandflies in northeastern Brazil. A total of 2,267 specimens belonging to eight genera and 15 species were sampled. The predominant species were Nyssomyia whitmani(34.41%) and Micropygomyia echinatopharynx(17.25%).The green LED trap prevailed over the blue and control lights; however, no statistically significant difference could be detected among the three light sources. Even without statistical significance, we suggest using LEDs as an attractant for the capture of sandflies because of several advantages over the conventional method with incandescent lamps.

Recent advances in phlebotomine sand fly research related to leishmaniasis control.

Phlebotomine sand flies are the subject of much research because of the role of their females as the only proven natural vectors of Leishmania species, the parasitic protozoans that are the causative agents of the neglected tropical disease leishmaniasis. Activity in this field was highlighted by the eighth International Symposium on Phlebotomine Sand flies (ISOPS) held in September 2014, which prompted this review focusing on vector control. Topics reviewed include: Taxonomy and phylogenetics, Vector competence, Genetics, genomics and transcriptomics, Eco-epidemiology, and Vector control. Research on sand flies as leishmaniasis vectors has revealed a diverse array of zoonotic and anthroponotic transmission cycles, mostly in subtropical and tropical regions of Africa, Asia and Latin America, but also in Mediterranean Europe. The challenge is to progress beyond descriptive eco-epidemiology, in order to separate vectors of biomedical importance from the sand fly species that are competent vectors but lack the vectorial capacity to cause much human disease. Transmission modelling is required to identify the vectors that are a public health priority, the ones that must be controlled as part of the integrated control of leishmaniasis. Effective modelling of transmission will require the use of entomological indices more precise than those usually reported in the leishmaniasis literature.

Control of vegetable pests in Benin - Farmers' preferences for eco-friendly nets as an alternative to insecticides.

We investigated if eco-friendly nets (EFNs) are a viable and acceptable alternative to extremely high levels of insecticide use in vegetable production. Using a choice experiment, we found that vegetable producing farmers in Benin preferred all of the characteristics of EFNs except the higher labor requirements. The nets had been distributed in a trial phase for free but in the long run farmers would need to purchase the EFNs. The break-even point for investing in nets was found to vary with the lifespan of EFNs, their purchase price and potential health benefits from avoiding large quantities of insecticides. To break even the nets need to be used for at least two production cycles. To overcome risk-averse farmer's reluctance to adopt EFNs we propose a credit and warranty scheme along with the purchase of the nets. The study's findings can guide the implementation of EFNs in other African countries as part of integrated pest management with global benefits for the environment and human health.