Benefits and Risks of Intercropping for Crop Resilience and Pest Management

Plant microbiome responses to bioinoculants and volatiles

BACKGROUND

There is an increase in the adoption of biological solutions for plant production as a means of attaining sustainable agriculture. A detailed understanding of the influence of specific bioinoculants and their volatile metabolites on native soil and plant microbiomes can improve future microbiome management practices.

RESULTS

Here, we examined the effect of bacterial inoculants and volatile compounds as individual and combined treatments on apple plant and soil microbiome. The study used specially designed microcosms that facilitated the separation of the different plant compartments. A compartment- and soil-specific effect of treatments on the native soil and plant microbiome was observed. The live bacterial inoculants as compared to their volatiles had a stronger effect on the plant and soil microbiome, particularly the root microbial community. The combined effect of bacterial inoculants was higher compared to volatiles (R2 = 5% vs. 3%). Treatment-specific effects were observed, like the influence of 2-butanone on the phyllosphere bacterial diversity, and an increase in fungal richness in Serratia-treated soils.

CONCLUSIONS

Among the examined treatments, inoculation with bacteria compared to volatile metabolites induced more significant shifts within the plant and soil microbiome. This observation has implications regarding the merits of applying living microorganisms. The findings highlight the potential of microbiome management approaches for enhancing microbiota functions.

Optimizing Fodder Yield and Quality Through Grass-Legume Relay Intercropping in the Mediterranean Region

An annual relay intercropping of grasses and legumes (LGI) (50:50) was compared with the sole crops, respectively, to determine the effect of the mixtures on the yield and quality of them as fodder in the Mediterranean region. The treatments were sole Rye (Secale cereale; G1), Ryegrass (Lolium perenne; G2), Faba bean (Vicia faba L.; L1), Berssem (Trifolium alexandrinum L.; L2), inoculated Clover (Trifolium alexandrinum L.; L3), and all the combinations of grasses and legumes. The experiment used a randomized block design with three blocks. ANOVA showed significant effects of intercropping on the biomass yield (BY) and the forage quality. Monocrops L2 and L3 showed better fodder quality than LGI and L1. The relative land-use efficiency (RLI) was higher for four out of six intercrops, while G2L1 and G2L3 had an RLI < 1, indicating lower efficiency than their monocrops. The Aggressivity Index (AG) showed that L1 was competitive against the grasses. The Relative Yield Maximization (RYM) demonstrated that intercropping significantly improved the biomass yield. The competition indices revealed that G1 with legumes had the highest efficiency and economic viability (ELER > 1), while the G2 combinations were less profitable. The study highlights the importance of selecting species based on soil fertility and climatic conditions to optimize intercropping outcomes.

Sustainable Management of Major Fungal Phytopathogens in Sorghum (Sorghum bicolor L.) for Food Security: A Comprehensive Review

Sorghum (Sorghum bicolor L.) is a globally important energy and food crop that is becoming increasingly integral to food security and the environment. However, its production is significantly hampered by various fungal phytopathogens that affect its yield and quality. This review aimed to provide a comprehensive overview of the major fungal phytopathogens affecting sorghum, their impact, current management strategies, and potential future directions. The major diseases covered include anthracnose, grain mold complex, charcoal rot, downy mildew, and rust, with an emphasis on their pathogenesis, symptomatology, and overall economic, social, and environmental impacts. From the initial use of fungicides to the shift to biocontrol, crop rotation, intercropping, and modern tactics of breeding resistant cultivars against mentioned diseases are discussed. In addition, this review explores the future of disease management, with a particular focus on the role of technology, including digital agriculture, predictive modeling, remote sensing, and IoT devices, in early warning, detection, and disease management. It also provide key policy recommendations to support farmers and advance research on disease management, thus emphasizing the need for increased investment in research, strengthening extension services, facilitating access to necessary inputs, and implementing effective regulatory policies. The review concluded that although fungal phytopathogens pose significant challenges, a combined effort of technology, research, innovative disease management, and effective policies can significantly mitigate these issues, enhance the resilience of sorghum production to facilitate global food security issues.

Crop Diversification for Ensuring Sustainable Agriculture, Risk Management and Food Security

Agriculture faces growing challenges from climate change, pest pressures, and market instability. Crop diversification offers a sustainable strategy to enhance resilience and reduce the risks of monoculture. This review examines crop diversification as a response to these challenges, with a focus on its applications in sustainable agriculture, risk management, and food security. Strategies such as spatial, temporal, genetic, and intercropping diversification enhance soil health, improve pest management, and boost resilience to climate variability. The review highlights key principles, including ecological resilience, risk distribution, and resource optimization. By adopting diverse crops, farmers can mitigate soil degradation, reduce pest outbreaks, and stabilize incomes. Successful case studies from various regions, such as integrated rice-fish farming and agroforestry, demonstrate how diversification can improve productivity and sustainability. However, challenges remain, such as knowledge gaps, market access issues, and policy limitations. The review concludes with recommendations for future research and policy interventions, stressing the need for tailored diversification strategies, better support systems, and further exploration of innovative practices. This overview underscores the potential of crop diversification to build resilient, sustainable agricultural systems while addressing global food security concerns.

Integrated Pest Management: An Update on the Sustainability Approach to Crop Protection

Integrated Pest Management (IPM) emerged as a pest control framework promoting sustainable intensification of agriculture, by adopting a combined strategy to reduce reliance on chemical pesticides while improving crop productivity and ecosystem health. This critical review synthesizes the most recent advances in IPM research and practice, mostly focusing on studies published within the past five years. The Review discusses the key components of IPM, including cultural practices, biological control, genetic pest control, and targeted pesticide application, with a particular emphasis on the significant advancements made in biological control and targeted pesticide delivery systems. Recent findings highlight the growing importance of genetic control and conservation biological control, which involves the management of agricultural landscapes to promote natural enemy populations. Furthermore, the recent discovery of novel biopesticides, including microbial agents and plant-derived compounds, has expanded the arsenal of tools available for eco-friendly pest management. Substantial progress has recently also been made in the development of targeted pesticide delivery systems, such as nanoemulsions and controlled-release formulations, which can minimize the environmental impact of pesticides while maintaining their efficacy. The Review also analyzes the environmental, economic, and social dimensions of IPM adoption, showcasing its potential to promote biodiversity conservation and ensure food safety. Case studies from various agroecological contexts demonstrate the successful implementation of IPM programs, highlighting the importance of participatory approaches and effective knowledge exchange among stakeholders. The Review also identifies the main challenges and opportunities for the widespread adoption of IPM, including the need for transdisciplinary research, capacity building, and policy support. In conclusion, this critical review discusses the essential role of IPM components in achieving the sustainable intensification of agriculture, as it seeks to optimize crop production while minimizing adverse environmental impacts and enhancing the resilience of agricultural systems to global challenges such as climate change and biodiversity loss.

Host-parasitoid trophic webs in complex agricultural systems

The composition and dynamics of ecological communities are complex because of the presence of large numbers of organisms, belonging to many different species, each with their own evolutionary history, and their numerous interactions. The construction and analysis of trophic webs summarize interactions across trophic levels and link community structure to properties such as ecosystem services. We focus on agroecological communities, which may be simpler than natural communities but nonetheless present considerable challenges to describe and understand. We review the characteristics and study of communities comprised of plants, phytophagous insects, and insect parasitoids with particular regard to the maintenance of sustainable agroecological communities and ecosystem services, especially biological pest control. We are constrained to largely overlook other members of these communities, such as hyperparasitoids, predators, parasites, and microbes. We draw chiefly on recent literature while acknowledging the importance of many advances made during the immediately preceding decades. Trophic web construction and analysis can greatly improve the understanding of the role and impact of herbivores and natural enemies in agroecological communities and the various species interactions, such as apparent competition, which assists biocontrol strategies. The study of trophic webs also helps in predicting community ecology consequences of externally driven changes to agroecosystems.

Effects of diversified volatile profiles on olfactory orientation of flea beetles Phyllotreta spp. and the diamondback moth Plutella xylostella

This study investigated the effect of mixing volatile organic compounds (VOC) emitted by host and non-host plants on the orientation of key pests of Brassicaceae. The study aimed to understand how these mixed VOCs influence pest behaviour, which could help in tailoring pest management strategies. The orientations of flea beetles, Phyllotreta spp., and the diamondback moth (DBM), Plutella xylostella, towards cabbage VOCs mixed with faba bean VOCs were assessed using Y-tube olfactometry. The pests' preferences were measured to determine if the presence of faba bean alongside cabbage altered their olfactory orientation compared to cabbage alone. Flea beetles showed a preference for cabbage VOCs alone over the cabbage-faba bean VOC mix. For DBM, no significant preference was observed between cabbage alone and the cabbage-faba bean mix. Previous findings indicated that faba bean attracts DBM, and in this study the mixture of cabbage and faba bean appeared to be more attractive than cabbage alone. The results indicate that faba bean VOCs can deter flea beetles from cabbage, potentially offering a pest management strategy. However, the effect on DBM was inconclusive, with no clear preference observed. This suggests that while faba bean VOCs may influence pest orientation, their effectiveness varies among different pest species. Additionally, herbivore damage to cabbage leaves did not appear to influence the odour-guided orientation of either pest, irrespective of the presence or absence of faba bean.

Sustainable Agricultural Development

Sustainable agricultural practices improve food security, increase farmers' profitability, and preserve the environment. By implementing sustainable farming methods such as crop rotation, integrated pest management, and conservation tillage, farmers can improve soil health, reduce water usage, and minimize agrochemical inputs. Moreover, sustainable agriculture promotes biodiversity and protects natural resources such as water and soil. Responsible farming practices preserve the environment and ensure that future generations access fertile land and clean water sources. Additionally, sustainable agriculture can help farmers achieve higher crop yields and better-quality produce, adapt to changing climate conditions, and mitigate the impact of climate change on food production. Sustainable agricultural practices are essential for ensuring food security, increasing farmers' profitability, and preserving the environment for future generations. We must continue to support and promote sustainable farming methods to create a more resilient and sustainable food system.

Integrating Metarhizium anisopliae entomopathogenic fungi with border cropping reduces black bean aphids (Aphis fabae) damage and enhances yield and quality of French bean

French bean growers, rely mainly on pesticides for pest management. The acceptable tolerance for pesticides residue in French beans is a major concern and has led to several tonnes of the crop continuously rejected and listed as unsafe for human consumption. There is growing demand for alternative approaches and products that are effective at managing pests without the side-effects associated with reliance on pesticides. A field study to determine the combined effects of Metarhizium anisopliae, (Metarril WP E9 and Biomagic) biopesticides and border crops (Sunflower and wheat) on aphid population, damage severity, growth, yield and quality of French bean. A two-factor experiment was conducted at the Egerton University, Kenya. First factor included two border crops (sunflower and wheat) and no border crop (control). Second factor included spraying Metarril WPE9 (2 × 108 cfu/g), Biomagic (2 × 108 cfu/ml) biopesticides, alpha-cypermethrin (synthetic insecticide) and water. Data on growth, yield and quality parameters were collected and analyzed using the SAS version 9.4M8. Results showed that M. anisopliae and border crop significantly (p < 0.0005) enhanced growth, yield and quality of French bean in both seasons. French bean grown with wheat or sunflower borders showed a significant reduction in aphid population (p < 0.0001) and damage severity (p < 0.0001) when sprayed with various treatments compared to the control. Plots with wheat border caused an increase in collar diameter of French bean. The plots (Metarril and wheat border) caused a 4 % and 5 % increase in marketable yield, a 2 % and 12 % reduction in non-marketable yield. To exploit the benefits of biopesticides, the study recommends their integration with and border crops. Thus, French bean growers could benefit more from fungal-based biopesticides in aphid-IPM approach, as it reduces pre-harvest intervals and residues compared to synthetic insecticides.

Knowledge, attitudes, and perceptions of farmers towards urban agroecology in Malaysia

Adopting agroecological approaches to build resilient urban food systems has recently gained traction around the world, but there is little to no reliable literature on the knowledge, attitudes, and perspectives of urban farmers towards these nature-based solutions in many developing nations, including Malaysia. The present study conducted an online survey to determine the extent to which local urban farmers understand and employ agroecology, as well as to assess their awareness and views on using agroecological practices and sustainable farm management. We found that the majority of respondents are unfamiliar with agroecological principles, with 79 % agreeing or strongly agreeing that implementing sustainable agricultural practices is challenging. However, more than 90 % of respondents are aware of the environmental consequences of excessive input utilisation. Our findings highlight the need for improved initiatives to promote agroecological approaches among farmers by sharing knowledge and best practices. In light of the growing threat posed by urban heat islands and the rapid urbanisation, this study offers novel insights into the knowledge gaps and perceptions about agroecological approaches among urban farmers, challenges that must be addressed to promote sustainable agriculture, and the potential role of farmers in achieving the three fundamental pillars of sustainability-planet, people, and prosperity.

Harnessing monocrop breeding strategies for intercrops

Intercropping is considered advantageous for many reasons, including increased yield stability, nutritional value and the provision of various regulating ecosystem services. However, intercropping also introduces diverse competition effects between the mixing partners, which can negatively impact their agronomic performance. Therefore, selecting complementary intercropping partners is the key to realizing a well-mixed crop production. Several specialized intercrop breeding concepts have been proposed to support the development of complementary varieties, but their practical implementation still needs to be improved. To lower this adoption threshold, we explore the potential of introducing minor adaptations to commonly used monocrop breeding strategies as an initial stepping stone towards implementing dedicated intercrop breeding schemes. While we acknowledge that recurrent selection for reciprocal mixing abilities is likely a more effective breeding paradigm to obtain genetic progress for intercrops, a well-considered adaptation of monoculture breeding strategies is far less intrusive concerning the design of the breeding programme and allows for balancing genetic gain for both monocrop and intercrop performance. The main idea is to develop compatible variety combinations by improving the monocrop performance in the two breeding pools in parallel and testing for intercrop performance in the later stages of selection. We show that the optimal stage for switching from monocrop to intercrop testing should be adapted to the specificity of the crop and the heritability of the traits involved. However, the genetic correlation between the monocrop and intercrop trait performance is the primary driver of the intercrop breeding scheme optimization process.

Biotechnological and socio-environmental potential of Campomanesia adamantium (Myrtaceae): an interdisciplinary review

Guavira (Campomanesia adamantium, Myrtaceae) is a native fruit from the Brazilian Cerrado savanna and is socio-economically important for the indigenous and traditional people living in the Central-West. This is a bibliographic review of the biological properties of guavira and its derivatives, and, after discussing experimental studies, an interdisciplinary approach is conducted highlighting the im-portance of Agroforestry Systems as an ecological restoration tool to leverage the production chain of guavira while providing ecosystem services. Many research groups studied effects of polyphenols and other bioactive compounds and biological properties of this fruit and other plant parts such as antibiotic, antioxidant, anti-inflammatory, anti-hyperlipidemic, anti-diarrheic and antitumoral activities, cardiovascular and hepatic protection and action against neuropathic pain. Besides, guavira by-products benefit poultry intestinal health, similarly to antibiotics added to their feed. Furthermore, several biotechnological products were found, like pulp flour, seasoning from the peel, sunscreen, and seed oil similar to olive oil with pharmaceutical and industrial potential. We conclude by emphasizing the importance of guavira for restoration and preservation of the threatened Brazilian Cerrado, and for the socio-environmental development of family agriculture. The same approach and study are welcome and necessary in other regions and domains worldwide having their native flora as means for a restorative end.

Assessment of molybdenum application on soybean physiological characteristics in maize-soybean intercropping

Soybean is a leguminous crop known for its efficient nitrogen utilization and ease of cultivation. However, its intercropping with maize may lead to severe reduction in its growth and yield due to shading effect of maize. This issue can be resolved by the appropriate application of essential plant nutrient such as molybdenum (Mo). Aim of this study was to assess the effect of Mo application on the morphological and physiological characteristics of soybean intercropped with maize. A two-year field experiment was conducted for this purpose, and Mo was applied in the form of sodium molybdate (Na2MoO4), and four different levels were maintained i.e., 0, 60, 120 and 180 g ha-1. Soybean exhibited varying responses to different levels of molybdenum (Mo) application. Notably, in both sole and intercropped cropping systems, the application of Mo at a rate of 120 g ha-1 demonstrated the highest level of promise compared to other application levels. However, most significant outcomes were pragmatic in soybean-maize intercropping, as application of Mo @ 120 g ha-1 significantly improved soybean growth and yield attributes, including leaf area index (LAI; 434 and 441%), total plant biomass (430 and 461%), transpiration rate (15 and 18%), stomatal conductance (9 and 11%), and yield (15 and 20%) during year 2020 and 2021 respectively, as compared to control treatment. Similarly, Mo @ 120 g ha-1 application resulted in highest total grain yield (626.0 and 725.3 kg ha-1) during 2020 and 2021 respectively, which exceeded the grain yields of other Mo levels under intercropping. Moreover, under Mo application level (120 g ha-1), grain NPK and Mo contents during years 2020 and 2021 were found to be 1.15, 0.22, 0.83 and 68.94 mg kg-1, and 1.27, 0.25, 0.90 and 72.18 mg kg-1 under intercropping system increased the value as compared to control treatment. Findings of current study highlighted the significance of Mo in enhancing soybean growth, yield, and nutrient uptake efficiency in maize-soybean intercropping systems.

Exploring the future of GM technology in sustainable local food systems in Colombia

The security of Earth's food systems is challenged by shifting regional climates. While agricultural processes are disrupted by climate change, they also play a large role in contributing to destabilizing greenhouse gases. Finding new strategies to increase yields while decreasing agricultural environmental impacts is essential. Tropical agriculture is particularly susceptible to climate change: local, smallholder farming, which provides a majority of the food supply, is high risk and has limited adaptation capacity. Rapid, inexpensive, intuitive solutions are needed, like the implementation of genetically modified (GM) crops. In the Latin American tropics, high awareness and acceptance of GM technologies, opportunities to test GM crops as part of local agricultural educations, and their known economic benefits, support their use. However, this is not all that is needed for the future of GM technologies in these areas: GM implementation must also consider environmental and social sustainability, which can be unique to a locality. Primarily from the perspective of its educators, the potential of a rural Colombian university in driving GM implementation is explored, including the role of this type of university in producing agricultural engineers who can innovate with GM to meet regionally-dependent environmental and cultural needs that could increase their sustainability.

Bio-Intensive Tactics for the Management of Invasive Fall Armyworm for Organic Maize Production

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an invasive pest native to the American continent. The present study focused on bio-intensive tactics like intercropping, using natural enemies, botanical insecticides and biopesticides for managing S. frugiperda for the organic production of maize in Indian conditions. A total of eight different parasitoids attacking the different stages of S. frugiperda viz., eggs and larvae were found in the study area. The total parasitism rate due to all the parasitoids ranged from 28.37 to 42.44%. The egg-larval parasitoid, Chelonus formosanus Sonan (Hymenoptera: Braconidae) was the dominant parasitoid (12.55%), followed by Chelonus nr. blackburni (Hymenoptera: Braconidae) (10.98%) and Coccygydium sp. (4.85%). About 36.58 percent of the egg masses collected was parasitized by egg parasitoids, among which Telenomus remus (Nixon) (Hymenoptera: Scelionidae) was the dominant parasitoid. The botanicals insecticides such as citronella and annona extract were most effective, resulting in 100% mortality of FAW larvae (168 h after treatment). The essential oil of garlic (100%) was found highly effective in inhibiting egg hatching, followed by geraniol (90.76%). The maize intercropped with lady's finger (okra) recorded significantly the lowest pest infestation and recorded higher grain yield (6.17 q/ha) than other intercropping systems and control (5.10 q/ha). The overall bioefficacy of commercial biopesticides against the larvae of S. frugiperda was in the following order azadirachtin > Metarhizium anisopliae (Metch.) Sorokin (Hypocreales: Clavicipitaceae) > Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) at 168 h after treatment.

Biological control interventions reduce pest abundance and crop damage while maintaining natural enemies in sub-Saharan Africa: a meta-analysis

Insect pests are a major challenge to smallholder crop production in sub-Saharan Africa (SSA), where access to synthetic pesticides, which are linked to environmental and health risks, is often limited. Biological control interventions could offer a sustainable solution, yet an understanding of their effectiveness is lacking. We used a meta-analysis approach to investigate the effectiveness of commonly used biocontrol interventions and botanical pesticides on pest abundance (PA), crop damage (CD), crop yield (Y) and natural enemy abundance (NEA) when compared with controls with no biocontrol and with synthetic pesticides. We also evaluated whether the magnitude of biocontrol effectiveness was affected by type of biocontrol intervention, crop type, pest taxon, farm type and landscape configuration. Overall, from 99 studies on 31 crops, we found that compared to no biocontrol, biocontrol interventions reduced PA by 63%, CD by over 50% and increased Y by over 60%. Compared to synthetic pesticides, biocontrol resulted in comparable PA and Y, while NEA was 43% greater. Our results also highlighted that the potential for biocontrol to be modulated by landscape configuration is a critical knowledge gap in SSA. We show that biocontrol represents an effective tool for smallholder farmers, which can maintain yields without associated negative pesticide effects. Furthermore, the evidence presented here advocates strongly for including biocontrol practices in national and regional agricultural policies.

Introduction to the Collection: Climate Change, Insect Pests, and Beneficial Arthropods in Production Systems

Climate change is expected to alter pressure from insect pests and the abundance and effectiveness of insect pollinators across diverse agriculture and forestry systems. In response to warming, insects are undergoing or are projected to undergo shifts in their geographic ranges, voltinism, abundance, and phenology. Drivers include direct effects on the focal insects and indirect effects mediated by their interactions with species at higher or lower trophic levels. These climate-driven effects are complex and variable, sometimes increasing pest pressure or reducing pollination and sometimes with opposite effects depending on climatic baseline conditions and the interplay of these drivers. This special collection includes several papers illustrative of these biological effects on pests and pollinators. In addition, in response to or anticipating climate change, producers are modifying production systems by introducing more or different crops into rotations or as cover crops or intercrops or changing crop varieties, with potentially substantial effects on associated insect communities, an aspect of climate change that is relatively understudied. This collection includes several papers illustrating these indirect production system-level effects. Together, biological and management-related effects on insects comprise the necessary scope for anticipating and responding to the effects of climate change on insects in agriculture and forest systems.