Biological Pest Control Research Articles

Distribution and accumulation of Cadmium in different trophic levels affecting Serangium japonicum, the predatory beetle of whitefly Bemisia tabaci, biologically, physiologically and genetically: An experimental study

Cadmium (Cd) is a heavy metal that is of great concern in agroecosystems due to its toxicity to plants, herbivores, carnivores, and human beings. The current study evaluated the allocation and bioaccumulation of Cd from soil to cotton plants, cotton plants to herbivore pests, and herbivorous pests to a natural enemy predator. When soil was spiked with 100 mg/kg Cd, results demonstrated that cotton roots accumulated more Cd than the stems and leaves. The bioaccumulation of Cd was less in 4th instar larvae, pupa, and adults of Serangium japonicum than in Bemisia tabaci adults. The bioaccumulation in S. japonicum elongated the immature development period and reduced adult longevity, oviposition days, fertility, and total pre-oviposition duration. The net reproduction of S. japonicum was also reduced, as was female mature weight and feeding potential; as a result, Cd exposure could reduce the future population size compared to uncontaminated populations. There was decreased activity of the antioxidant enzymes (SOD, CAT, and POD) and energy-conserving lipids (glycogen, triglyceride, and total cholesterol) in Cd-contaminated S. japonicum compared to controls. The detoxifying enzyme activity of GST and P450 increased while AChE activity did not change. The qRT-PCR research showed that SOD1, CAT, POD, glycogen, and triglyceride gene expression was higher than in controls, whereas detoxification gene expression did not change. Our results indicate that Cd exposure has a physiological trade-off between its adverse effects on life history traits and elevated detoxification and antioxidation of S. japonicum, which could result from gene expression alteration. Further studies are needed to assess whether Cd exposure causes irreversible DNA damage in S. japonicum.

Simulating immunosuppressive mechanism of Microplitis bicoloratus bracovirus coordinately fights Spodoptera frugiperda.

Parasitoid wasps control pests via a precise attack leading to the death of the pest. However, parasitoid larvae exhibit self-protection strategies against bracovirus-induced reactive oxygen species impairment. This has a detrimental effect on pest control. Here, we report a strategy for simulating Microplitis bicoloratus bracovirus using Mix-T dsRNA targeting 14 genes associated with transcription, translation, cell-cell communication, and humoral signaling pathways in the host, and from wasp extracellular superoxide dismutases. We implemented either one-time feeding to the younger instar larvae or spraying once on the corn leaves, to effectively control the invading pest Spodoptera frugiperda. This highlights the conserved principle of "biological pest control," as elucidated by the triple interaction of parasitoid-bracovirus-host in a cooperation strategy of bracovirus against its pest host.

A biobased superabsorbent formulation for above-ground application of a new entomophthoralean fungus for biological psyllid pest control

Entomophthoralean fungi have long been recognized as promising candidates for biological insect pest control. However, due to technical challenges, no preparation based on these fungi has been established for practical use so far. Low water availability is a key limiting factor of conidial discharge and germination. In the present study, sporulation of psyllid-pathogenic entomophthoralean fungus Pandora cacopsyllae Eilenberg, Keller and Humber (Entomophthorales Entomophthoraceae) was not observable under reduced water activity (aW ≤ 0.97). To support sporulation of encapsulated P. cacopsyllae hyphae from submerged culture under low humidity conditions in above-ground applications in field, we developed a novel paste-type formulation containing biobased superabsorbents, which retained water for a prolonged time period. In co-application with the superabsorbent formulation, the otherwise fast-drying capsules were kept sufficiently moist for sporulation for at least six days in laboratory trials at low humidity below 40%. Using the new formulation, we measured conidial discharge by P. cacopsyllae from the capsules under dry semi-field conditions in summertime by trapping conidia at a vertical distance of up to 40 cm from the sporulation source. By considering the cardinal directions, fewer conidia were discharged on the sun-facing side in the east than on the sun-averted side in the west. The developed formulation improved the sporulation efficacy significantly. Since water availability is a limiting factor for many fungal biocontrol agents, the developed formulation has the potential to also improve their efficacy.

The Prospect of Hydrolytic Enzymes from Bacillus Species in the Biological Control of Pests and Diseases in Forest and Fruit Tree Production.

Plant diseases and insect pest damage cause tremendous losses in forestry and fruit tree production. Even though chemical pesticides have been effective in the control of plant diseases and insect pests for several decades, they are increasingly becoming undesirable due to their toxic residues that affect human life, animals, and the environment, as well as the growing challenge of pesticide resistance. In this study, we review the potential of hydrolytic enzymes from Bacillus species such as chitinases, β-1,3-glucanases, proteases, lipases, amylases, and cellulases in the biological control of phytopathogens and insect pests, which could be a more sustainable alternative to chemical pesticides. This study highlights the application potential of the hydrolytic enzymes from different Bacillus sp. as effective biocontrol alternatives against phytopathogens/insect pests through the degradation of cell wall/insect cuticles, which are mainly composed of structural polysaccharides like chitins, β-glucans, glycoproteins, and lipids. This study demonstrates the prospects for applying hydrolytic enzymes from Bacillus sp. as effective biopesticides in forest and fruit tree production, their mode of biocidal activity and dual antimicrobial/insecticidal potential, which indicates a great prospect for the simultaneous biocontrol of pests/diseases. Further research should focus on optimizing the production of hydrolytic enzymes, and the antimicrobial/insecticidal synergism of different Bacillus sp. which could facilitate the simultaneous biocontrol of pests and diseases in forest and fruit tree production.

Management practices influence biocontrol potential of generalist predators in maize cropping systems

AbstractIntensification of conventional agriculture is a leading cause of negative environmental impact, loss of biodiversity, and reduced delivery of ecosystem services in agroecosystems. Maize, due to its growth habits and cultivation management, provides a poor habitat for beneficial arthropods. Several strategies are available to make maize cropping systems more sustainable and to promote biodiversity at field level. The present study evaluates the effects of various maize cropping systems – precisely, maize continuous monoculture, maize multiple cropping, and three mixed cropping systems (maize‐runner bean, maize‐sorghum, and maize‐flower strips) – on generalist predators and their biological control potential. Overall, we found that the reference system with maize continuous monoculture and conventional crop management had the lowest activity of generalist predators compared in particular to the low‐input mixed cropping systems. Higher activity density and biocontrol potential were found in the systems that provided a dense and permanent vegetation cover of the ground (i.e., maize/sorghum, maize/flower strip). Although these effects were not consistent for all the parameters investigated and for every sampling date, we conclude that generalist predators can benefit from more conservative management practices in maize systems, thereby enhancing their biological pest control potential. Furthermore, spatial intercropping may represent a valid alternative to the conventional monocultural crop system to support the delivery of biodiversity‐mediated ecosystem services towards a more sustainable system.

The application of entomopathogenic nematode modified microbial communities within nesting mounds of the red imported fire ants, Solenopsis invicta

Entomopathogenic microorganisms (e.g., fungi, bacteria, nematodes) have been widely used in biological control of soil-dwelling pests, including the red imported fire ant (RIFA), Solenopsis invicta, a notorious invasive pest worldwide. The application of large amounts of entomopathogenic microorganisms to soil may affect the indigenous soil microbial communities. However, reports about the effect of entomopathogenic nematodes (EPN) on soil microbial communities are very few. In this study, the effects of EPN on RIFA populations and microbial communities in mounds were investigated. Our results showed that the application of the EPN Steinernema carpocapsae. All strain on mounds efficaciously suppressed RIFA worker populations, without forming significantly more satellite mounds compared with the control treatment. The application of EPN did not impact the bacterial and fungal diversity in soils derived from the RIFA mounds. However, it slightly altered the taxonomic make-up of the bacterial communities, but significantly altered the taxonomic composition of fungal communities at the phylum, family, and genus levels. The abundances of some beneficial bacteria and fungi, such as Streptomyces, decreased, while those of plant and animal pathogenic bacteria and fungi, dramatically increased, after EPN treatment. On the other hand, the abundances of some entomopathogenic fungi, such as Fusicolla, Clonostachys, and Mortierella, increased. Redundancy analysis or canonical correspondence analysis revealed a positive correlation between the efficacious EPN control and the presence of the insect-resistant bacteria, Sinomonas, as well as entomopathogenic fungi Fusicolla and Mortierella. This suggests that the interactions between EPN and entomopathogenic fungi may play a role in the biological control of RIFA. Our discoveries shed light on the interactions among EPN, RIFA, and soil microbial communities, and emphasize a possible mutualistic relationship between EPN and entomopathogenic fungi in the biological control of RIFA.

Bacterial and Fungal Endophytes of Grapevine Cultivars Growing in Primorsky Krai of Russia

In this study, the biodiversity of endophytic bacteria of cultivated grape varieties from the vineyards of Primorsky Krai, Russia, was analyzed for the first time. Far Eastern grape varieties with a high level of stress resistance are a unique object of research as they are cultivated in cold and humid climates with a short summer season. Grapevine endophytic microorganisms are known as promising agents for the biological control of grapevine diseases and agricultural pests. Using genomic approaches, we analyzed the biodiversity of the endophytic bacteria and fungi in the most common grape varieties of Primorsky Krai, Russia: Vitis vinifera × Vitis amurensis cv. Adele (hybrid No. 82-41 F3), Vitis riparia × V. vinifera cv. Mukuzani (pedigree unknown), two cultivars Vitis labrusca × V. riparia cv. Alfa, and Vitis Elmer Swenson 2-7-13 cv. Prairie Star for the first time. The main representatives of the endophytic microorganisms included 16 classes of bacteria and 21 classes of fungi. The endophytic bacterial community was dominated by Gammaproteobacteria (31–59%), followed by Alphaproteobacteria (9–34%) and, to a lesser extent, by the classes Bacteroidia (9–22%) and Actinobacteria (6–19%). The dominant fungal class was Dothideomycetes (43–77%) in all samples analyzed, with the exception of the grapevine cv. Mukuzani from Makarevich, where Malasseziomycetes was the dominant fungal class. In the samples cv. Alfa and cv. Praire Star, the dominant classes were Tremellomycetes and Microbotriomycetes. A comparative analysis of the endophytic communities of the cultivated grape varieties and the wild grape V. amurensis Rupr. was also carried out. We found that 18–20% of the variance between the endophytic communities accounted for the differences between the cultivated and wild grapevines, while the factors “plant location” and “individual plants” accounted for 50–56% and 3–10% of the variance, respectively. The results of this study can be used to develop new means of biocontrol in vineyards to protect plants from abiotic stresses and pathogens.

The strategy of optimal control for managing sugarcane shoot borer larvae

Pests and plant diseases pose significant challenges to Indonesia's agricultural development of sugar cane. The fall in national sugar productivity can be attributed, in part, to the presence of sugar cane shoot borer bugs. Managing sugar cane shoot borer pests is a crucial aspect of agriculture. The objective of this scientific study is to ascertain the optimal approach for the introduction of parasitoid larvae of sugarcane shoot borer pests. This will be done by looking at the Lotka-Volterra equation's stability and finding the best way to control it. This is a mathematical model used to show how biological control systems work. Specifically, the study focuses on the biological control of sugarcane shoot borer pests using their parasitic larvae, the Diatraeophaga striatalis Towns. The researchers opted for the qualitative descriptive approach, employing analytical tools derived from Miles and Huberman's four-stage framework. The equilibrium point and optimal control analyses show that the model presents various outcomes with distinct methods. These findings will be further examined in the subsequent sections of this paper.

Impacts of landscape heterogeneity on bottom-up effects affecting biological control

Conservation biological control of crop pests by natural enemies relies on management strategies to favour their trophic interactions. In agricultural landscapes, natural enemies acting across habitat boundaries may feed on non-pest prey, resulting in apparent competition between non-pest prey and pests. Such communities, including pests, non-pest prey, and natural enemies have been shown to be affected by landscape heterogeneity depending on the dispersal capacity of the interacting organisms. Nonetheless, a mechanistic understanding of how natural enemies’ dispersal capacity interacts with landscape heterogeneity affecting conservation biological control is, however, lacking. Here, we contribute to such mechanistic understanding through modelling. We simulated the consequences of differences in landscape heterogeneity defined by the contrast of plant resource distribution in a semi-natural habitat compared to a crop and variation in natural enemy dispersal capacity on biological control of a pest. Our model showed that variation in plant resource distribution resulted in bottom-up effects that led to shifts in the dominant mechanism underlying biological control. At high landscape heterogeneity when resources differ strongly between crop and the semi-natural habitat, non-pest prey benefitted from the plant resources available, promoting apparent-competition-mediated biocontrol for high-dispersing natural enemies. At low landscape heterogeneity, pests benefitted mostly from plant resources available, promoting direct plant-pest-enemy mediated biocontrol. Interestingly, intermediate levels of landscape heterogeneity resulted in the lowest levels of biocontrol. Our results highlight the importance of potential bottom-up effects that the matching between plant resources available in a habitat and the resource preference of herbivores can induce on conservation biological control.

Intercropping Okra and Castor Bean Reduces Recruitment of Oriental Fruit Moth, Grapholita molesta (Lepidoptera: Tortricidae) in a Pear Orchard.

Intercrops can lower pest densities by increasing plant diversity, altering chemical communication in the arthropod community, and integrating well with other IPM tactics. We used two years of field observations and Y-tube olfactometer assays to explore the effects of intercropping a pear orchard with okra and castor bean on the cosmopolitan fruit-boring pest Grapholita molesta (Lepidoptera: Tortricidae). Intercropping okra reduced G. molesta trap catches in the pear orchard in both years, and intercropping with castor bean reduced them in the second year. Hydrocarbons, phenols, and ketones predominated in the GC-MS assay of okra volatiles, whereas castor bean volatiles were rich in aldehydes, ketones, and esters. Five of the commercially available volatiles released by these plants exhibited repellency to G. molesta in olfactometer trials, especially cinnamaldehyde, dibutyl phthalate, and thymol; the former compound also exhibited attraction to the egg parasitoid Trichogamma dendrolimi (Hymenoptera: Trichogrammatidae). In addition to their repellent properties, okra and castor bean may enhance integrated control of G. molesta in orchards by hosting prey that support populations of generalist predators that either provide biological pest control services within the orchard ecosystem or generate non-consumptive effects that contribute to pest deterence. Among the plant volatiles evaluated, cinnamaldehyde has the best potential for deployment in orchards to repel G. molesta without disrupting augmentative releases of T. dendrolimi.

Efficiency of temperature and storage duration on some morphological measurements and reproductive capacity of the entomopathogenic nematode Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae)’s Turkish HBH hybrid strain

Entomopathogenic nematodes (EPNs) are successfully used in the biological control of agricultural insect pests. This study aims to determine the body length of hermaphrodite individuals, egg diameter and reproductive capacity obtained from Infective Juveniles (IJs) stored at different temperatures and durations. Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae)’s Hybrid Strain HBH was used in the study. IJs stored at 15, 25 and 35°C for 7, 14 and 21 days were inoculated onto Galleria mellonella L., 1758 (Lepidoptera: Pyralidae) last instar larvae at a dose of 100 IJs. On the 2nd day of infection, hermaphrodite individuals and eggs were obtained by dissecting the larvae. The reproductive capacity was determined 10-12 days after infection. The study was conducted in Bursa Uludağ University, Faculty of Agriculture, Plant Protection Department, Nematology Laboratory in 2023. In conclusion, the longest hermaphrodite individuals and egg diameter were obtained as 6207.22 µm and 55.65 µm, respectively from the IJs stored for 7 days at 15°C. The highest reproductive capacity was also observed as 167.500 IJs per G. mellonella larva in IJs stored under the same conditions with respect to temperature and time. This study is important for assessing the morphological effects of different temperature values and storage durations on EPNs.

Naturally Occurring Vegetation Connectivity Facilitates Ant-Mediated Coffee Berry Borer Removal.

Vegetation connectivity is an essential aspect of the habitat complexity that impacts species interactions at local scales. However, agricultural intensification reduces connectivity in agroforestry systems, including coffee agroecosystems, which may hinder the movement of natural enemies and reduce the ecosystem services that they provide. Ants play an important role in regulating the coffee berry borer (CBB), which is the most damaging coffee pest. For arboreal ant communities, the connections between trees are important structures that facilitate ant mobility, resource recruitment, foraging success, and pest control ability. To better understand how connectivity impacts arboreal ants in coffee agroecosystems, we conducted an experiment to assess the impact of artificial (string) and naturally occurring vegetation (vines, leaves, branches) connectivity on Azteca sericeasur behavior on coffee plants. We compared ant activity, resource recruitment, and CBB removal rates across three connectivity treatments connecting coffee plants to A. sericeasur nest trees: vegetation connectivity, string, and control (not connected) treatments. We found higher rates of ant activity, resource recruitment, and CBB removal on plants with naturally occurring vegetation connections to A. sericeasur nest trees. Artificial connectivity (string) increased the rates of resource recruitment and CBB removal but to a lesser extent than vegetation connectivity. Moreover, vegetation connectivity buffered reductions in ant activity with distance from the ant nest tree. These results reinforce how habitat complexity in the form of vegetation connectivity impacts interspecific interactions at the local scale. Our results also suggest that leaving some degree of vegetation connectivity between coffee plants and shade trees can promote ant-mediated biological pest control in coffee systems.

Corpse Management Strategies in Social Insects

Social insects are arthropods that lives in a community with other members of the same species. Eusocial insects frequently lose colony members as a result of living in big groupings. They perform cooperative corpse management to maintain the hygiene of the nest, exhibiting behavioural and physiological responses that promote disease resistance, nutrient reallocating and colony protection. Undertaking behaviour is most common in social insects belonging to Hymenoptera and Isoptera which adopts various mechanisms of death recognition, convergent and divergent behavioural responses towards dead items. Corpse removal, burial, cannibalism and avoidance are different solutions evolved by social insects, independently towards the problem of corpse management. Genetic studies and gene expression analysis related to social immune systems gives a better knowledge on behavioural and physiological disease defense in insects which could be considered a novel access to biological pest control. This article provides a comprehensive understanding of corpse management in social insects.

Detection of Pine Wood Nematode Infestation Based on Improved YOLOv5

Pine wilt disease is a destructive forest disease caused by the parasitism of pine wood nematodes inside pine trees. Once infected, pine trees quickly wither and die due to the inability to drain water, hence it is also known as pine tree withering disease. It is mainly spread by pine sawyer beetles, with the characteristics of fast dissemination, rapid onset, and high mortality rate, making it a significant global plant disease. Failure to effectively control the pine wilt disease in a timely manner will result in the massive death of pine trees in a short period of time in forest areas. With the continuous development and popularization of artificial intelligence and UAV (Unmanned Aerial Vehicle) technology, combining various methods can timely detect diseased trees, and performing timely treatment and protection can greatly save the time and personnel costs of biological pest control. While it is also conducive to promoting the work of multiple related disciplines, such as bioengineering and greening engineering. In this paper, we first conducted a large number of aerial surveys on the forest area through UAV, collected relevant data, and preprocessed the obtained data, including data augmentation, cleaning, filtering, deduplication, formatting, etc., to ensure data quality and accuracy. Then, we labeled the data, and made certain improvements to the original YOLOv5. We added a new RRAM (Recurrent Residual Attention Module) to the original network model, which enables the network to timely focus on important information in redundant data, thus improving the network’s performance. Compared with the original YOLOv5, our network has a stronger performance.

Use of Fertilizers and Pesticides in Vegetable Growing and their Impact on the Ecosystem in the Comoé River Watershed, Burkina Faso

Background an Aims: The use of pesticides and chemical fertilizers has been practised for centuries to control pests and increase agricultural productivity. However, mismanagement of these products can entail health and environmental risks. This study was initiated to assess the impact of these practices on the CRW ecosystem. The aim of this study is to characterize pesticide and fertilizer use practices in vegetable growing in the Comoé river watershed (CRW).
 Study Design: This study was carried out on a sample of market gardeners chosen randomly. Data collection was done transversally.
 Place and Duration of Study: This study was conducted in Western Burkina Faso during the dry period of 2020. It concerned market gardeners who carry out their activity in the Comoé Basin.
 Methodology: To this end, a survey was carried out among a representative sample of 204 vegetable growers. The survey sheet was used to collect information on the level of education, speculations, origins of fertilizers and pesticides, and the management of fertilizers and pesticides in the CRW.
 Results: The study revealed that local vegetable growers use both organic and chemical fertilizers. They obtain their supplies from the local market. In fact, 91% of the vegetable growers interviewed use both types of fertilizer. Growers are unaware of the validity period of the products they use. In addition, 48% of growers say they do not know or do not pay attention to the expiry date of products. Furthermore, 82% of growers do not master fertilizer application doses. Current pesticide and fertilizer use practices are risky, and the dangers incurred are pollution, particularly water pollution, and its consequences on human and environmental health (soil, vegetation, etc.). It would therefore be wise to encourage and promote biological pest control in order to preserve human and animal health and the environment.

Caputo and Conformable Fractional Order Guava Model for Biological Pest Control: Discretization, Stability and Bifurcation

Abstract Two predator-prey model describing the guava borers and natural enemies are studied in this paper. Positivity, existence, and uniqueness of the solution, global and local stability analysis of the fixed points of the first model based on the Caputo fractional operator are studied. By adding piecewise constant functions to the second model including conformable fractional operator allows us to transition discrete dynamical system via discretization process. Applying Schur-Cohn criterion to the discrete system, we hold some regions where the equilibrium points in the discretized model are local asymptotically stable. We prove that discretized model displays supercritical Neimark–Sacker bifurcation at the equilibrium point. Theoretical and numerical results show that the discretized system demonstrates richer dynamic properties such as quasi-periodic solutions, bifurcation, and chaotic dynamics than the fractional order model with Caputo operator. All theoretical results are interpreted biologically and the optimum time interval for the harvesting of the guava fruit is given.

Herbicides may threaten advances in biological control of diseases and pests.

Advances in agriculture include integrated methods of controlling pests, diseases, and weeds with biocontrollers, which are constantly increasing, along with herbicides. The objective is to present a systematic review of the main reports of herbicide effects on non-target organisms used in applied biological control and those naturally occurring in the ecosystems controlling pests. The categories were divided into predatory and parasitoid arthropods. Three hundred and fifty reports were analyzed, being 58.3% with parasitoids and 41.7% with predators. Lethal or sublethal effects of herbicides on reproduction, predation, genotoxicity, and abundance of biological control organisms have been reported. Two hundred and four reports of the impact of herbicides on parasitoids were analyzed. The largest number of reports was with parasitoids of the genus Trichogramma, with wide use in managing pests of the herbicide-tolerant transgenic plants. Most tests evaluating effects on parasitism, emergence, and mortality of natural enemies subjected to herbicides are with parasitoids of Lepidoptera eggs with a high diversity and use in managing these pests in different crops. Additive and synergistic effects of molecules increase the risks of herbicide mixtures. Herbicide use for weed management must integrate other control methods, as the chemical can impact natural enemies, reducing the biological control of pests.

Spontaneous flowering vegetation favours hoverflies and parasitoid wasps in apple orchards but has low cascading effects on biological pest control

Floral resources support several ecosystem services in agroecosystems, such as pollination or biological control. Many beneficial organisms feed on nectar or pollen for an important part of their life cycle. Providing adequate and sufficient floral resources through the conservation of spontaneous flowering vegetation may be a strategy to improve biological pest control. However, the role of spontaneous flowering plant species has mainly been evaluated in the recruitment of natural enemies. Cascading effects on pest regulation and damage reduction are rarely studied. Here we evaluated the effect of spontaneous flowering vegetation on pest regulation in 18 Mediterranean apple orchards. We focused on two main apple pests, Cydia pomonella and Dysaphis plantaginea, and on two groups of their natural enemies depending on floral resources: hoverflies and parasitoid wasps. We combined generalised linear mixed models and piecewise structural equation models to test for direct and indirect effects of spontaneous flowering plant species on beneficial insects (hoverflies, parasitoid wasps, wild bees and honeybees) and on pest regulation. We also tested for potential negative interactions between honeybees and hoverflies, parasitoid wasps or wild bees. There was a positive and significant effect of insect-pollinated flowers on hoverflies, parasitoid wasps and bees, but small cascading effects on D. plantaginea or C. pomonella density and associated damage. There was no significant relationship between honeybees and hoverflies, parasitoid wasps or wild bees. The reduction of D. plantaginea infestation was partially mediated by hoverfly abundance. Furthermore, we observed effects of spontaneous flowering vegetation on pest regulation and damage reduction independent of hoverfly and parasitoid wasp abundances. These results highlight the importance of conserving floral resources to support biological control of apple pests. Further studies are needed to better understand interactions between spontaneous flowering vegetation and crop management practices to promote sustainable pest regulation strategies.

ICT4Agroecology part I: outcomes for cassava production system

ABSTRACT This study discusses the results of a 5-year Agroecology Research and Advocacy project at three Tanzanian field sites in different agroecological zones. We investigated four common agroecological practices: compost application, mulching, intercropping, and biological pest control either alone or in combination. Two custom-built ICT tools – AgroEco Research (AER) and AgroEco Analysis (AEA) application – supported the field research. AER and AEA integration allowed secure data storage and real-time automated visualization and statistical analyses without programming. At no field station did legume intercropping or biological pest control increase cassava yields. The Chambezi field station had the highest yields even under untreated control conditions and only here, soil fertility amendments further increased root weights. Intercropping with cowpea legumes, alone or in combination with other practices, had no significant effect on cassava plant size or survival at the Mumbaka and Vianzi field sites and even negatively affected one or both parameters. Organic pest control had no effect on any target variable, except for plant size at Chambezi. Therefore, labor-intensive and expensive pest control practices may not be worth the investment at least when virus-resistant cassava varieties like Kiroba are used.

Extracting Venom from the Parasitoid Wasp Trichogramma dendrolimi using an Artificial Host.

Parasitoid wasps are a diverse group of hymenopteran insects that serve as invaluable resources for pest biocontrol. To ensure successful parasitism, parasitoid wasps inject venom into their hosts to suppress their hosts' immunity, modulate hosts' development, metabolism, and even behavior. With over 600,000 estimated species, the diversity of parasitoid wasps surpasses that of other venomous animals, such as snakes, cone snails, and spiders. Parasitoid wasp venom is an underexplored source of bioactive molecules with potential applications in pest control and medicine. However, collecting parasitoid venom is challenging due to the inability to use direct or electrical stimulation and the difficulty in dissection because of their small size. Trichogramma is a genus of tiny (~0.5 mm) egg parasitoid wasps that are widely used for the biological control of lepidopteran pests in both agriculture and forests. Here, we report a method for extracting venom from T. dendrolimi using artificial hosts. These artificial hosts are created with polyethylene film and amino acid solutions and then inoculated with Trichogramma wasps for parasitism. The venom was subsequently collected and concentrated. This method enables the extraction of large amounts of Trichogramma venom while avoiding contamination from other tissues caused by dissection, a common issue in venom reservoir dissection protocols. This innovative approach facilitates the study of Trichogramma venom, paving the way for new research and potential applications.