Study of the Constraints of Millet Production (Pennisetum glaucum (L.) R. Br.) and the Peasant Perception of Biological Control in the Tahoua Region

Millet (Pennisetum glaucum (L.) R. Br.) is the Sahelian crop par excellence due to its adaptation to the particular production conditions in this region. Unfortunately, in recent years this crop has been threatened by very strong parasitic pressure and drought during the production period. The objective of this study is to analyze the main constraints of millet production and the solutions known to producers. A survey was carried out in November 2022 with a sample of 298 producers in five municipalities in the Tahoua region. The main constraints are drought and pressure from crop pests (locust, millet ear miner, floricultural insects) according to 57.9% of respondents. The millet ear miner is the most formidable pest according to 55% of respondents. Thus, the average yield obtained in a year of good production without the leafminer is 194 kg/ha and that obtained in a year of millet ear leafminer is around 27 kg to 43 kg/ha depending on the municipality. The yield obtained this last campaign after the attack of this leafminer varies from 64 to 77 kg/ha depending on the municipalities compared to a potential yield of over 1000 kg/ha. More than half of producers (58.1%) are unaware of the existence of biological control compared to only 12.5% who are aware of this alternative method. Work to popularize this technology is necessary in the five municipalities and the entire region in general.

Identification and Characterization of Lysobacter enzymogenes as a Biological Control Agent Against Some Fungal Pathogens

Strain OH11, a Gram-negative, nonspore forming, rod-shaped bacterium with powerful antagonistic activity, was isolated from rhizosphere of green pepper in Jiangsu Academy of Agricultural Sciences of China and characterized to determine its taxonomic position. 16S rRNA gene sequence analysis revealed that strain OH11 belongs to the Gammaproteobacteria and had the highest degree of sequence similarity to Lysobacter enzymogenes strain C3 （AY074793） （99%）, Lysobacter enzymogenes strain N4-7 （U89965） （99%）, Lysobacter antibioticus strain （AB019582） （97%）, and Lysobacter gummosus strain （AB16136） （97%）. Chemotaxonomic data revealed that strain OHI 1 possesses a quinine system with Q-8 as the predominant compound and C15：0 iso, C17：1 iso ω9c as the predominant iso-branched fatty acids, all of which corroborated the assignment of strain OH11 to the genus Lysobacter. Results of DNA-DNA hybridization and physiological and biochemical tests clearly showed that strain OH11 was classified as Lysobacter enzymogenes. Strain OH11 could produce protease, chitinase, and β-1,3-glucanase. It showed strong in vitro antifungal activity against Rhizoctonia solani, Sclerotinia scletotiorum, and several other phytopathogenic fungi. This is the first report of identification and characterization of Lysobacter enzymogenes as a biological control agent of plant diseases in China.

Integrated Biological Control of Tobacco Bacterial Wilt (<i>Ralstonia solanacearum</i>) and Its Effect on Rhizosphere Microbial Community

Biological control agents and soil amendments have been applied to control tobacco bacterial wilt, but the mechanism is not well-known. In the present study, a field experiment was performed to investigate the soil physicochemical properties, disease index (DI) and disease incidence of tobacco bacterial wilt, and rhizosphere microbial community. The results show that the control efficacy of single application of antagonistic bacteria and calcium cyanamide was 46.43% and 51.92%, respectively. While the combined control efficacy of antagonistic bacteria and calcium cyanamide was 65.79%. Besides, the combined application of antagonistic bacteria and calcium cyanamide could increase soil pH, total N alkaline N, and exchangeable Ca, which were negatively associated with the microbial diversity, soil-borne pathogenic microorganisms, and incidence of tobacco bacterial wilt. Additionally, the combination of antagonistic bacteria and calcium cyanamide can improve the proportion of some antagonistic microbial species, and these antagonistic microbial species were inversely associated with the DI of tobacco bacterial wilt. In conclusion: The integrated measure may influence soil microbial communities through enhancing soil physicochemical properties and rebuild healthy soil microbial community structure to mitigate tobacco bacterial wilt. The current study presented valuable insights into the mechanisms enhancing soil health in the integrated measure.

Controlling Dengue: Effectiveness of Biological Control and Vaccine in Reducing the Prevalence of Dengue Infection in Endemic Areas

With the increased prevalence of dengue infection in tropical countries, concerned members of the public are now pressing their local health ministries to act immediately and effectively in managing the rising numbers of reported cases. This includes reviews of the methodologies and the effectiveness of current combative systems to find other possible novel approaches that might yield better results. One of those novel approaches is the integration of a parasite into mosquito vector, manipulating the parasite-host interaction to reduce the transmission of dengue in endemic hotspots. Another alternative is by Sanofi-Pasteur’s dengue vaccine that showed over 60.8% success rate in reducing severe dengue infection in children aged 9 - 16 during its final clinical implementation phase. This report will compare and contrast these two novel ideas to determine which of the approaches are more likely to be effective in the long run. The aspects covered will include the application, effectiveness, functionality, and problems with these approaches. The results could then be utilised by governments or organizations to select precise and effective methods in reducing the prevalence of dengue infections in their countries.

Primary Study on Biological Control Potential of Trichoderma harzianum TL-1

Trichoderma harzianum is a widely used biocontrol fungus. The growth promoting effect of strain Trichoderma harzianum TL-1 on tomato and pepper and its biological control effects against tomato seedling damping-off and pepper blight were investigated through pot experiments. The results showed that the stain TL-1 had significant promotion effect on growth of pepper and tomato in sterilized and natural soils. With the application dose of 3. 0 and 0. 5g/ pot,their dry weight were increased up to 46% and 150% compared with control,respectively. In addition,TL-1 had good control effects against tomato seedling damping-off and pepper blight. Compared with fungicide treatment,TL-1 treatment could control diseases for long term,without repeat occurrence of diseases.

An Attenuated Strain of Cucumber Green Mottle Mosaic Virus as a Biological Control Agent against Pathogenic Viral Strains

Cucumber green mottle mosaic virus (CGMMV), a member of the Tobamovirus genus, causes a severe disease of cucurbits. In the Moscow region of Russian Federation, the incidence of infection on cucumber plants in greenhouses is high;however, the virus is poorly studied. In this work, the full-length genomes of two pathogenic MC-1 and MC-2 strains of CGMMV isolated from cucumber plants grown in greenhouses in the Moscow region and the attenuated VIROG-43M strain were sequenced. Comparison of VIROG-43M nucleotide sequence with those of the pathogenic strains revealed three missense mutations. Their role in attenuation is discussed. For the first time, in a number of trials conducted under laboratory conditions and in commercial greenhouses, the efficiency of the attenuated VIROG-43M strain as a biocontrol agent for cucumber plant protection resulting in significant yield gain was demonstrated. Phylogenetic analysis with 83 full-length CGMMV coat protein genes isolated in 16 different countries showed that Russian strains are related to isolates from Spain, Greece, USA and Israel.

Biological control of rice disease and insect by chitinase-producing bacterium X2-23

Enriched by the-medium containingchitin and cell wall of Phizoctoniasolani AG-1,a bacterium X2-23 withhigher chitinase activity was isolatedfrom 166 chitinase-producing bacteria.It could distinctly inhibit the fungi

Biological Control of Erosion of Banana Drains in Côte D’ivoire

The erosion of drains is a major limitation of the quality, the increasing of banana production and the environmental protection of industrial banana in C&#244;te d'Ivoire. It leads inundations, death of banana trees and significant loss of production. Thence, the construction and the maintenance of drain costs too much and causes injure, snake bite, physical traumatisms, many diseases, … These events compromise the sustainable production of banana by reducing seriously worker’s the activities and finally increase the cost of production. The aim of the present work is to contribute to the sustainable development and human capacity building in the third world nations as far as banana production is concerned. The methods used so far to address this phenomenon proved inefficient. The technology innovation in this area has been to grow grass on the outer edges of the channels drained water. This resulted in a systematic reduction of erosion. Better still, it helped fertilize the soil, reduce the deportations of fertilizer and improve the quality of landscape of the plantations. Stenotaphrum secondatum is the best vegetable specie adapted to the biological control against water erosion of drains.

The Use and Exchange of Biological Control Agents for Food and Agriculture

The report sets out to summarize the past and current situation regarding the practice of biologicalcontrol inrelationtothe use and exchange of genetic resources relevant for BCAs.It considers the twomain categories of biological control:classical and augmentative.Allowing access to BCAs for use inanother country imposes no risk of liability to the source country.Local scientific knowledge abouthabitats,fauna andflora,can be

Effects of Plant Growth Promoting Rhizobacteria (PGPR) on In Vitro Bread Wheat (Triticum aestivum L.) Growth Parameters and Biological Control Mechanisms

Three endemic plants rhizosphere (Astragalus gombo Coss. & Dur., Daucus sahariensis Murb., Ononis angustissima Lam.), were used for actinomycetes isolation. Ninety-three (93) isolates have been screened to evaluate their antagonistic properties against phytopathogenic microorganisms and to determine their biocontrol properties against Fusarium culmorum, especially responsible for several cereal diseases like font’s seedlings, rust, and burn of ears. Four (04) isolates (D2, D5, D8, and AST1) have been in vitro tested to determine PGPR effect and biocontrol characters of bread wheat (Triticum aestivum L.), Hidhab (HD) variety cultivated in the Murashigue and Skoog (MS) culture medium. The aim of this study is the evaluation of antagonistic isolates of pathogenic fungi F. culmorum, without and within commercial fungicide (Tebuconazole, 60 g/l) solution. Our results showed clearly that these isolates have a significant effect on seed germination and seedling growth. However, results argue that these actinomycetes isolates show a very interesting activity compared to the commercial fungicide. As a result, these bacteria isolates can be used as biocontrol agents against Fusarium wilt disease of wheat, which have a beneficial effect on growth parameters.

Biological Control of Erwinia carotovora ssp. carotovora by Streptomyces Species

Ten isolates of Erwinia carotovora ssp. carotovora (Ecc) were isolated from infected potato tubers of Picasso, Sante, and Nevskiy varieties collected from different regions in Kyrgyzstan. Isolates were identified as Erwinia carotovora ssp. carotovora (Ecc) by standard bacteriological techniques and pathogenicity tests on tubers and also by PCR analyses. Tests on the pathogenicity of E. carotovora ssp. carotovora (Ecc) strains to host plants by artificial inoculation have shown a high sensibility of the Picasso variety. As a result, five isolates were chosen, three isolates (EcPo1, EcPo2, and Eco3) were highly pathogenic, while two isolates (Eco4 and Eco5) were weakly pathogenic. The antagonistic bacteria, Streptomyces diastatochromogenes strain sk-6, and Streptomyces graminearuss strain sk-2, have a highly significant effect on soft rot bacteria isolates (Ecc), more than the other tested antagonistic organisms in vitro screening biotests. The Streptomyces diastatochromogenes sk-6 was selected for the control assay of storage potatoes against the most common soft rot bacterial strain in Kyrgyzstan, Erwinia carotovora sp. carotovora EcPo2. The pretreatment of potato tubers with antagonistic bacteria successfully prevented the initial infection multiplication of soft rot bacteria and reduced soft rot disease of potatoes in storage. These results justify selection of the dose 106 cells/ml of bacteria Streptomyces diastatochromogenes sk-6 for use in powdering the infected or non-infected potato tubers to suppress the development soft rot during storage. Streptomyces diastatochromogenes sk-6 as a biological disinfectant could destroy surface and internal infections, protect the tubers from the growth of phytopathogenic bacteria in the early period of their reproduction, and improve the overwintering of winter crops.

Potential of Steinernema carpocapsae(Weiser) as a biological control agent against potato tuber moth, Phthorimaea operculella(Zeller)(Lepidoptera: Gelechiidae)

The entomopathogenic nematode,Steinernema carpocapsae,was evaluated for control of the potato tuber moth,Phthorimaea operculella,under laboratory conditions.We evaluated different concentrations of S.carpocapsae for control of 2 nd,3 rd,and 4 th instar P.operculella.The median lethal concentration(LC50)of S.carpocapsae infective juveniles(IJs)to 2 nd,3 rd and 4 th instar larvae of P.operculella was 200,363,181 IJs mL–1,respectively.With the extension of treatment time,the cumulative mortality increased for 2 nd,3 rd,and 4 th instar larvae and pupae of P.operculella.Fourth instars were the most susceptible for all observation periods.Therefore,our results suggest that S.carpocapsae could be an effective biological control agent for P.operculella.

Identification of Motor Nuclei in the Medulla Oblongata of Carp for Biological Control

Brain-controlled technology is the key technology in biological control,and the corresponding relationship between animal brain nuclei and motor behavior is the core.The purpose of this study was to explore the motor nuclei of the medulla oblongata in carp.The carps were subjected to electrical stimulation and chemical stimulation experiments,respectively,in the water-free state,and the effective chemical stimulation sites were injected with the pontamine sky blue solution.The brain tissue sections were obtained by paraffin tissue section technology and the neutral red staining method.By comparing the positions of the brain nuclei shown in earlier studies,the motor nerve nuclei in the medulla oblongata were identified.The brain electrode was implanted into the motor nucleus of the medulla oblongata,and the underwater control experiment and behavioral tests were carried out with different electrical stimulation parameters.The results showed that the abducens nucleus(NVI)was the motor nucleus that controls the ipsilateral steering,and the facial nucleus(NVII)was the motor nucleus that controls the forward movement.By adjusting the stimulation voltage and the stimulation pulse number,the carp can be stably controlled to achieve a left–right steering motion of 30°–180°and a forward motion of more than 80 cm/s.This study indicated that the quantitative control of the steering and forward behavior of the carp can be achieved by electrical stimulation of the NVI and NVII,which provided a certain experimental basis for the accurate control of the carp robot.

Secondary Metabolites of Entomopathogenic Fungi, Biological Alternative for the Control of Agricultural Pests and Disease: Present and Perspectives

The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.

Flavonoid-producing tomato plants have a direct negative effect on the zoophytophagous biological control agent Oriussauteri

Orius sauteri(Poppius)(Hemiptera:Anthocoridae)is often used for biological control of small arthropod pests in greenhouse vegetable production systems in Asia.In addition to feeding on arthropod prey,O.sauteri consumes small quantities of plant material.Previous studies demonstrated that tomato plant chemistry confers antixenosis resistance to phloem-feeding whiteflies,but the potential nontarget effects of phytochemicals on the beneficial predator O.sauteri are unknown.Comparison of O.sauteri confined to near-isogenic lines(NILs)of tomatoes producing high levels offlavonoids(NIL-purple hypocotyl;resistant to whiteflies)and low levels of flavonoids(NIL-green hypocotyl;susceptible to whiteflies)revealed that O.sauteri had reduced oviposition,nymphal survival,and development on resistant plants,even if they were also provided with prey that did not feed on the host plant.Moreover,O.sauteri showed a significant ovipositional preference in choice assays,laying significantly more eggs on susceptible than on resistant plants.Molecular gut content analysis using the specific chloroplast trnL gene from tomato confirmed that adult and immature O.sauteri feed on both resistant and susceptible genotypes,and feeding behavior assays revealed that resistance did not affect plant feeding or prey acceptance by O.sauteri adults.These results demonstrate a direct negative effect of phytochemicals on a nontarget beneficial species and indicate that resistance mediated by phytochemicals can affect organisms that do not solely feed on phloem sap.The results also indicate that the mode of action and the potential ecological effects of phytochemicalmediated resistance are broader than previously recognized.

Rice(Oryza sativa L.)plant protection using dual biological control and plant growth-promoting agents:Current scenarios and future prospects

Various microorganisms live in association with different parts of plants and can be harmful,neutral,or beneficial to plant health.Some microbial inhabitants of plants can control plant diseases by contesting with,predating on,or antagonizing plant pathogens and by inducing systems for plant defense.A range of methods,including plant growth-promoting microorganisms(PGPMs)as biological control agents(BCAs)(BCA-PGPMs)are used for the biological management and control of plant pathogens.Some BCAs interact with plants by inducing resistance or priming plants without direct interaction with the pathogen.Other BCAs operate via nutrient competition or other mechanisms to modulate the growth conditions for the pathogen.Generally,PGPMs can be applied alone or together with other chemicals or carriers to control various crop diseases.This review highlights the effective types of BCA-PGPMs and their applications,roles,carrier based-formulations,and responses to rice(Oryza sativa L.)pathogens.Future plant disease management prospects are promising,and growers’increasing demand for BCA-PGPM products can be exploited as an effective approach to the management of plant diseases,as well as to improve yield,environmental protection,biological resources,and agricultural system sustainability.

Coffee Leaf Rust(Hemileia vastatrix)Disease in Coffee Plants and Perspectives by the Disease Control

Coffee Leaf Rust(CLR)is caused by Hemileia vastatrix in Coffea spp.It is one of the most dangerous phytopathogens for coffee plantations in terms of coffee productivity and coffee cup quality.In this review,we resume the problem of CLR in Mexico and the pathogenesis of H.vastatrix.The review abord plant-pathogen interactions which lead a compatible or incompatible interactions and result in CLR disease or resistance,respectively.The review abord Coffea spp.defense response pathways involved in H.vastatrix pathogenicity.Additionally,current measures to control H.vastatrix proliferation and germination were aborded focused on phytosanitary actions,and biological and chemical control.Finally,new trendlines to reduce the impact of CLR as nanoparticles and nanotechnology were analyzed.

Control of Lymantria dispar L. by biological agents

The experiment on control of Lymantria dispar L by using different kinds ofbiological measures, including nuclear polyhedrosis virus (NPV) of Lymantria dispar L., BtMP-342,sex-attractant as well as botanical insecticide, was carried out in the forest regions of InnerMongolia in 2003. Two concentrations (2.632x10^6 PIB ? ml^(-1) and 2.632x10^7 PIB ?ml^(-1)) of Lymantria dispar L. NPV were sprayed on the 2rd-instar-larvae of L. dispar and 70% and77.8% control effect were obtained respectively. BtMP0-342 was applied to the 3rd- and 4th-instarlarvae and the control effect was around 80%. The sex-attractant provided by Canada Pacific ForestryResearch Center also showed a good result in trapping L. dispar adults. The self-produced botanicalinsecticide, which was extracted from a kind of poisonous plant distributed in Daxing'an Mountains,China, exhibited a good control result in controlling the larvae of L. dispar, and 82% mortalitywas observed when spraying primary liquid of the botanical insecticide on the 3rd-5th-instar-larvaein lab.

Energy budgets of the Chinese green lacewing （Neuroptera： Chrysopidae） and its potential for biological control of the cotton aphid （Homoptera： Aphididae）

Energy budgets of larval stages of the Chinese green lacewing, Chrysopa sinica （Tjeder） （Neuroptera： Chrysopidae） were determined under laboratory conditions at photoperiod of 14：10 L：D, 27 ± 1℃ and 75% ± 2% RH. The energy used as ingestion, assimilation, respiration, productivity and feces was constructed for each developmental stage. In addition, under these experimental conditions, the potential of C. sinica as a biological control agent was evaluated according to the ingestion by this predator and the energy content of cotton aphid, Aphis gossypii （Glover） （Homoptera： Aphididae）. The larval stage of C. sinica was able to consume 1281.4 1-day-old aphids, 1018.7 2-day-old aphids, 626.9 3-day-old aphids, 393.5 4-day-old aphids, 312.1 5-day-old aphids or 203.5 9-day-old aphids, respectively. No significant difference was detected between the estimated number of aphids consumed by the lacewings using energetic methods and the actual number of aphids consumed by the lacewings in this experiment. Our results showed that C. sinica is an important natural enemy of the cotton aphid, and energetic methods are very useful to quantify biological control efficacy of natural enemies.

Fire Blight Disease Caused by Erwinia amylovora on Rosaceae Plants in Kyrgyzstan and Biological Agents to Control This Disease

Erwinia amylovora species were isolated from the blossoms, exudates, infected fruits, leaves and bent branches of diseased apple, pear and hawthorn trees, selected in the Chy, Osh and Jalal Abad regions. Biochemical and pathogenicity tests, alongside PCR analyses, were conducted to identify the local isolates of Erwinia amylovora. The alternative antagonistic microorganisms which combat bacterium E. amylovora were tested within in vitro and in vivo conditions. The results revealed the ability of Streptomyces antagonistic bacteria to decrease fire blight severity on pear and apple trees during the first stage of the fire blight disease in leaf tissues. Streptomyces strain C1-4 suppressed E. amylovora disease symptoms in the leaf tissues and excised apple and pear shoots. The incidence of fire blight on leaves was reduced by about 70% with two applications of bacterial antagonists. Further studies at different locations in Kyrgyzstan, using large scale application, would allow for stronger recommendations to be made, including studies and recommendations on their ability to prevent disease and to use them as main components in an integrated pest management program.