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Crop protection is an important issue and major challenge in agriculture worldwide, especially when confronting global climate change, biological invasions and declining agricultural biodiversity of recent decades.
Sustainable and environment-friendly agricultural pest management are required to achieve the sustainable development goals in agriculture. In this case, an advanced accurate prediction of monitoring and early warning system could be the first step in crop
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● An overview of impacts of climate change on wheat and rice crops. ● A review on impacts of climate change on insect pests and fungal pathogens of wheat and rice. ● A selection of adaptation strategies to mitigate impacts of climate change on crop production and pest and disease management.
Ongoing climate change is expected to have impacts on crops, insect pests, and plant pathogens and poses considerable threats to sustainable food security. Existing reviews have summarized impacts of a changing climate on agriculture, but the majority of these are presented from an ecological point of view, and scant information is available on specific species in agricultural applications. This paper provides an overview of impacts of climate change on two staple crops, wheat and rice. First, the direct effects of climate change on crop growth, yield formation, and geographic distribution of wheat and rice are reviewed. Then, the effects of climate change on pests and pathogens related with wheat and rice, and their interactions with the crops are summarized. Finally, potential management strategies to mitigate the direct impacts of climate change on crops, and the indirect impacts on crops through pests and pathogens are outlined. The present overview aims to aid agriculture practitioners and researchers who are interested in wheat and rice to better understand climate change related impacts on the target species.
● Crop pests are a major factor restricting agricultural production in China. ● The National Monitoring and Early Warning System (NMEWS) was established > 40 years ago. ● Application of NMEWS has increased national capability to tackle pests.
The importance of food security, especially in combating the problem of acute hunger, has been underscored as a key component of sustainable development. Considering the major challenge of rapidly increasing demands for both food security and safety, the management and control of major pests is urged to secure supplies of major agricultural products. However, owing to global climate change, biological invasion (e.g., fall armyworm), decreasing agricultural biodiversity, and other factors, a wide range of crop pest outbreaks are becoming more frequent and serious, making China, one of the world’s largest country in terms of agricultural production, one of the primary victims of crop yield loss and the largest pesticide consumer in the world. Nevertheless, the use of science and technology in monitoring and early warning of major crop pests provides better pest management and acts as a fundamental part of an integrated plant protection strategy to achieve the goal of sustainable development of agriculture. This review summarizes the most fundamental information on pest monitoring and early warning in China by documenting the developmental history of research and application, Chinese laws and regulations related to plant protection, and the National Monitoring and Early Warning System, with the purpose of presenting the Chinese model as an example of how to promote regional management of crop pests, especially of cross border pests such as fall armyworm and locust, by international cooperation across pest-related countries.
• Stripe rust caused substantial yield losses in China. • P. striiformis is highly variable and the change from avirulence to virulence. • Different comprehensive control strategies were adopted in different epidemic region.
Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici occurs in almost all wheat-producing regions of the world. Severe countrywide epidemics in China have caused substantial yield losses. Growing resistant cultivars is the best strategy to control this disease but the pathogen can overcome resistance in wheat cultivars. The high variation in the virulence of the pathogen combined with the large areas of susceptible wheat cultivars enables the pathogen population to increase rapidly and disperse over long distances under favorable environmental conditions, resulting in severe pandemics within cropping seasons. Current stripe rust control measures are based on many years of research including the underlying epidemiology regarding year-to-year survival of the pathogen, pathways of pathogen dispersal within seasons and years, the role of P. striiformis sexual hybridization, the use of resistance sources in breeding programs, and year-round surveillance of national wheat crops that are present in different parts of the country throughout the year. All these strategies depend on accurate prediction of epidemics, more precise use of fungicides to meet national requirements and better deployment of resistance genes. New ideas with potential application in sustainable protection of stripe rust include negative regulatory gene editing, resistance gene overexpression and biological control based on microbiomes.
• Soil solarization achieved 100% control of Bradysia cellarum. • The initial growth of Chinese chive was lower in solarized than control plots, but 20 d after treatment plants in the solarized had recovered and leaf height and yield were equivalent among the treatments. • Soil microbial community diversity in the treatment group first decreased and then recovered gradually, and abundance of beneficial microorganisms increased significantly.
Bradysia cellarum Frey (Diptera: Sciaridae) is an important subterranean pest and is especially damaging to Chinese chive. An effective and more environmentally safe method than pesticides is needed for its control. The efficacy of B. cellarum control, growth of Chinese chive and soil microbial diversity were investigated after uae of soil solarization to exterminate this insect pest. The results show that on the first day after soil solarization 100% control of B. cellarum was achieved. Growth of Chinese chive was lower in solarized plots than in control plots over the first 10 d after treatment. Chive growth in solarized plots increased subsequently to match that in the control plots. Moreover, the soil microbial community diversity in the treatment group decreased initially before gradually recovering. In addition, the abundance of beneficial microorganisms in the genus Bacillus and the phyla Proteobacteria, Chloroflexi and Firmicutes increased significantly. Soil solarization is therefore practical and worthy of promotion in Chinese chive-growing regions.
● Most entomophagous arthropods consume nectar or pollen as alternative diets. ● The attractive of floral resource with different traits varies in a wide degree. ● Floral resource plays positive effects on not only entomophagous insects but also agricultural biodiversity, multiple ecosystem services and crop production.
There is a growing demand for high-quality agricultural products and more countries have adopted landscape management by sowing flowering plants in agricultural fields as an important branch of conservation biological control. However, there has been less concern over the interactions and trade-offs between floral plants and entomophagous arthropods. This paper review progress in pollen/nectar feeding habits of entomophagous insects including parasitoids and predators which are important natural enemies of crop pests in agricultural fields. Factors that influence the preference of different guilds of natural enemies are reviewed to guide the selection of flowering plants in conservation biological control practices. Most studies find that floral resources have positive effects on both biological traits of natural enemies and their abundance and diversity, and this is believed to contribute greatly to pest control. Furthermore, the potential impacts of floral resources on crop yields are also discussed with an emphasis on a guild of entomophagous insects that provides both pest control and pollination services.
● Application of plant defense inducers against tea diseases. ● Application of natural enemies against insect pests. ● Application of Trifolium repens against weeds.
The application and development of ‘green’ preventive technologies in tea plantations is an important means of ensuring tea quality and ecological safety. Ecological, agronomic and biological controls are the main preventive measures used in Guizhou Province. This paper summarizes the ‘green’ preventive technologies being applied in Guizhou tea plantations, including the use of plant defense inducers to regulate tea plant responses to pathogens, natural enemies to control pest species causing damage to shoots and Trifolium repens to control the main weed species. In addition, it summarizes the integrated ‘green’ preventive technologies being used in Guizhou and provides a foundation for the ecological maintenance of tea plantations.
•Wide use of botanical insecticides is limited by the availability of certain plants. •Studies are needed to improve RNAi efficiency and to assess their safety risk. •Microbial insecticides are promising, but they only control a narrow range of pests. •Multitarget approach should be a promising strategy in future pest control. •Nanoformulation could enhance stability and control the release of bioinsecticides.
Bioinsecticides are naturally-occurring substances from different sources that control insect pests. Ideal bioinsecticides should have low toxicity to non-target organisms. They should also be easily degraded in sewage treatment works and natural environments, highly effective in small quantities and affect target pests only. Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development. However, to develop bioinsecticides into mainstream products, their high production costs, short shelf-life and often uncertain modes of action need to be considered. This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives, plant-incorporated protectants, and microbial bioinsecticides. The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.
• Research findings on the insect-virus interaction • Influences of immunity, feeding and microorganisms on virus transmission • Latest applications for virus control strategies
About 80% of plant viruses are transmitted by specific insect vectors, especially hemipterans with piercing-sucking mouthparts. Many virus-transmitting insects are also important crop pests that cause considerable losses in crop production. This review summarizes the latest research findings on the interactions between plant viruses and insect vectors and analyzes the key factors affecting insect transmission of plant viruses from the perspectives of insect immunity, insect feeding, and insect symbiotic microorganisms. Additionally, by referring to the latest applications for blocking the transmission of animal viruses, potential control strategies to prevent the transmission of insect-vectored plant viruses using RNAi technology, gene editing technology, and CRISPR/Cas9+ gene-driven technology are discussed.
• Developed a two-step synthetic route to anti-plant-virus candidate NK0238. • NK0238 exhibited a broad antivirus spectrum in greenhouse. • NK0238 showed comparable antivirus activities as controls in field trials. • NK0238 was safe to birds, fish, bees and silkworms. • NK0238 has a very good prospect in commercial development.
It has previously been shown that tryptophan, the biosynthesis precursor of Peganum harmala alkaloids, and its derivatives have anti-TMV activity both in vitro and in vivo. Further exploration of this led to the identification of NK0238 as a highly effective agent for the prevention and control of diseases caused by plant viruses, but the existing routes are unsuitable for its large-scale synthesis. This study optimized a route for two-step synthesis of this virucide candidate via reaction of l-tryptophan with triphosgene to produce l-tryptophan-N-carboxylic anhydride, which then reacts with n-octylamine to give NK0238 at up to 94% yield and nearly 97% HPLC purity. In addition, the route was used for the preparation of NK0238 on a>40 g scale permitting further assessment of its antivirus activity in the greenhouse and field experiments, and toxicity tests. NK0238 exhibited useful antiviral activities against a variety of viruses both in greenhouse and field experiments. The toxicity tests showed that NK0238 was not acutely toxic to birds, fish, honey bees and silkworms. The optimized route provides a solid foundation for its large-scale synthesis and subsequent efficacy and toxicity studies, its excellent activity and safety make NK0238 a promising drug candidate for further development.
● Lysobacter enzymogenes mutants were generated for WAP-8294A biosynthesis. ● Essential and non-essential accessory genes for WAP-8294A biosynthesis were determined. ● Six new WAP-8294A analogs were identified using UHPLC-HR-MS/MS. ● Three deoxy analogs were detected supporting the function of ORF4 in asparagine hydroxylation.
Naturally-occurring environmental microorganisms may provide ‘green’ and effective biocontrol tools for disease management in agricultural crops. Due to the constant threat of resistant pathogens there is a pressing and continual need to search for new biocontrol tools. This study investigated the production of new analogs of WAP-8294A compounds by the biocontrol agent Lysobacter enzymogenes OH11 through biosynthetic engineering. WAP-8294As are a family of natural cyclic lipodepsipeptides with potent activity against Gram-positive bacteria. A series of genetic manipulations was therefore conducted on the accessory genes in the WAP biosynthetic gene cluster. The resulting strains containing a single-point mutation in ORF4, which was predicted to encode a 2-ketoglutarate dependent dioxygenase, produced deoxy-WAP-8294As. This result provides evidence for the function of ORF4 in catalyzing β-hydroxylation of the D-asparagine residue in WAP-8294As. In addition, six new analogs of WAP-8294As were identified by UHPLC-HR-MS/MS. This is the first attempt to produce new WAP-8294As in Lysobacter and shows that the spectrum of the biocontrol compounds may be expanded through the manipulation of biosynthetic genes.
• HPPD is one of the most promising targets for new herbicides. • A family of novel HPPD inhibitors based on the triketone-quinoxaline scaffold was designed and synthesized. • One particular product (7d) gave the highest inhibition of HPPD of the newly synthesized derivatives. • Triketone-quinoxaline derivatives provide a useful molecular scaffold for the discovery of novel HPPD-inhibiting herbicides.
p-Hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) belongs to the family of Fe(II)-dependent non-heme oxygenases that occur in the majority of aerobic organisms. HPPD has proved to be a promising target in herbicide research and development. A battery of novel triketone-quinoxaline compounds has been designed using a structure-based drug design strategy and then prepared. Enzyme inhibition assays show that these synthesized derivatives possess favorable inhibition capability against Arabidopsis thaliana HPPD with IC50 values ranging from 0.317 to 0.891 μmol·L−1. Subsequently, the molecular docking results indicate that two adjacent carbonyls of the triketone moiety of the representative compound 2-(2,3-dimethyl-8-(o-tolyl)quinoxaline-6-carbonyl)-3-hydroxycyclohex-2-en-1-one (7d) engage in chelation with the ferrous ion of A. thaliana HPPD in a bidentate pose, and its quinoxaline scaffold forms two sets of parallel π-stacking interaction between two phenylalanine residues (Phe424 and Phe381). In addition, the extended phenyl group also interacts with Phe392 in a π-π stacking way. This study indicates that triketone-quinoxaline is a promising scaffold for discovering HPPD inhibitors with substantially increased potency, providing insight into the molecular design of new herbicides.
Plant pests and diseases have significant negative impacts on global food security, world trade and rural livelihoods. Climate change exacerbates these impacts in certain parts of the world. Overreliance on pesticides as the primary tool for plant pest management leads to problems such as pesticide resistance and pest resurgence. Environmental and food safety concerns are also associated with overuse of pesticides in crop production. There is clearly a need for a shift in pest management strategies and practices globally. Optimization of structures and functions in crop production agroecosystems through soil conservation practices and cropping diversification can improve pest regulation services provided in the systems. Prioritization of safer alternatives and practices in the IPM pyramid, such as resistant varieties and biopesticides, helps minimize the use of potentially risky agricultural inputs such as synthetic pesticides. Investment is needed to boost the development of innovative green technologies and practices. Production, distribution, use and regulatory capacities need to be strengthened to facilitate large-scale adoption of green technologies and practices. Finally, policy, financial and market instruments should be wielded to provide an enabling environment for the transformation to sustainable plant pest and disease management strategies and practices worldwide.
