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.

Investigation of Kiwifruit Bacterial Canker Disease(Pseudomonas syringae pv.Actinidiae Takikawa) in Guanzhong Area of Shanxi Province and Its Biological Control

[ Objective ] The paper was to grasp the incidence characteristic of kiwifruit bacterial canker disease （Pseudomonas syrirtgate pv. actinidiae Takikawa） in Guanzhong area of Shanxi province, and to screen the endophytic actinomycetes with control effect against kiwifruit bacterial canker. [ Method] The incidence characteristics of kiwifruit bacterial canker disease in 65 orchards of 13 villages in guanzhong area of Shanxi province （Yangling, Zhouzhi, Meixian） were investiga- ted and analyzed. The antagonistic strains against Pseudomonas syringae were simultaneously screened from 242 endophytic actinomycetes, and carried out field dis- ease control test. [ Result] The average incidence rate of kiwifruit bacterial canker disease in guan^ong area of Shanxi province was 7.95% ; the variety of kiwifruit had dose relationship with incidence rate. 76 strains bad inhibition activity agmnst P. syringae, while the inhibition zone diameters of fermentation broths of 35 strains against P. syr/ngae were greater than 20 nun. TIASA5 strain had inhibition activity against four target bacteria; gCLA4 strain not only had inhibition activity against four target bacteria, but also had strong inhibition activity against 10 species of plant pathogenic fungi. Field test showed that the fermentation broth of gCLA4 strain had obvious control effect against kiwifruit bacterial canker disease, and the relative control effect at 21 d could reach 66.7%. [ Conclusion] The an- tibacterial spectrum of fermentation broth of gCLA4 strain is broad, so gCLA4 strain has the potential to be developed into a broad-spectrum agricultural fungicide. Key words Kiwifruit bacterial canker disease; Endophytic actinomycetes; Biological control; Field test

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.

Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids

Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for insect pests and their natural enemies. In Japan, granuloviruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids of A. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both viruses and parasitoids affect the outcome of virus-parasitoid interactions.

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.

Integrated biological control of water hyacinths, Eichhornia crassipes by a novel combination of grass carp, Ctenopharyngodon idella (Valenciennes, 1844), and the weevil, Neochetina spp.

The efficacy of grass carp Ctenopharyngodon idella （Cyprinidae） and weevils Neochetina spp. （Curculionidae） to control the aquatic weed, water hyacinth, is investigated in a square net cage （happas） setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within ll0 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg （day 1） to 0.33 kg （day 110） when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually.

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.

A Mechanism for Biological Control-Tempo-Spatial Synchronization of Natural Enemy and Insect Pest Population Dynamics at the Peak by Increase of Biodiversity

To reveal the mechanism of control of the Woolly Apple Aphid （Eriosoma lanigerum Hausm, WAA） by increase of biodiversity in the apple orchard, a consecutive two-year field trials were conducted in Yurman province, China. The results showed that the peak of natural enemy density curve in the cover cropping orchard was well temporally synchronized with that of the WAA density on trees, but did not synchronize with that of WAA density on trees in clean orchard. In addition, the frequency of natural enemies and WAA within a same sample in cover cropping orchard was obviously higher than that in clean cultivated orchard during the peak of population curves, indicating that natural enemies spatially synchronized with aphids. The density of WAA for the whole growing season in cover cropping orchard was much less than that in clean orchard. Therefore, the temporal-spatial synchrony of natural enemy and aphid populations was proposed as one of the mechanisms for aphid control in cover cropped orchards.

Research Progress on Occurrence and Biological Control of Citrus Blue Mold

Citrus blue mold. is an important disease of Citrus postharvest storage and transportation, and a major factor affecting the long-term storage of citrus. The pathogens, harm symptoms as well as the infection circulation of Citrus blue mold were introduced, followed by a summary of the progress on the biological control of Citrus blue mold in recent years, with the aim to provide references for the prevention and control of Citrus blue mold.

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.

Utilization of Fungi for the Biological Control of Insect Pests and Ganoderma Disease in the Indonesian Oil Palm Industry

Biological control is usually the first choice of control and prevention method for integrated pest management （IPM） strategies and has now been widely implemented by Indonesian oil palm plantations. Entomopathogenic fungus, i.e., Metarhizium anisopliae, Cordyceps militaris and Beauveria bassiana have been demonstrated to control renowned pests of oil palm. Metarhizium has been used to control Oryctes larvae and the mortality has ranged from 91.67% to 100% in laboratory and 7.4% to 88.75% in the field. Metarhizium has been applied in combination with a termite baiting system （TBS） to control termites in the field for preventive and curative action as well. In many oil palm plantations in Indonesia, Cordyceps has been used to reduce the field moth population ofSetothosea asigna. Application of Cordyceps within the oil palm circle was able to infect S. asigna pupae up to 80%. Meanwhile, Beauveria in an effervescent formulation was demonstrated to have better efficacy on Darna trima larvae. A significant finding on the biological control of basal stem rot disease （Ganoderma） was the isolation of Trichoderma sp. and Gliocladium sp.. The efficacy was conducted with promising result and techniques on the application of Triehoderma have been developed, i.e., hole-in-hole system, surgery and a mounding method. However, as the roots developed, Trichoderma was no longer able to protect the palm from Ganoderma. In spite of that, the use of Trichoderma still prolonged the life ofoil palms by up to 2-3 years. Another fungi belonging to vesicular arbuscular mychorrhiza （VAM） has been developed to control Ganoderma. The efficacy in the nursery showed promising results and the Ganoderma incidence remained low compared to the untreated control. Large scale field trials are ongoing. Challenges on the implementation of biological control in oil palm plantations are because of application and availability of biopesticides/natural enemies. Therefore, advances in research on the formulation of biological control agents are still needed.

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.

Study on Biological Control Of Rhlzoctonla solanl vla Trlchoderma

Strain T02-25 was selected from approximately 30 rhizosphere isolates of Trichoderma species isolated from roots of crops. Its biological activity against Rhizoctonia solani was determined for the control efficacy to pepper seedling blight caused by R. solani in the field. The assay methods were treating R. solani sclerotia by Trichoderma conidial suspension (10^6cfu ml^-1) and scattering Thichoderma rice bran over the pepper root medium. The results showed that T02-25 was active against R.solani in both ways, and its control efficacy was 82.7% and 78.0%, respectively. In addition to comparison of the efficacy of the two application methods, the relationship of different factors in the control efficacy of Trichoderma against R. solani was discussed.

Modified Predator-Prey Model for Mealybug Population with Biological Control

Mealybugs are a major pest for many crops （such as the vegetable Cassava, in Thailand）. An environmentally-friendly bio-control method is implemented using an introduced predator （green lacewings） of the mealybugs to mitigate plant damage. This is analyzed so as to devise and determine an optimal strategy for control of the mealybug population. A predator-prey model has been proposed and analyzed to study the effect of the biological control of the spread of the mealybugs in the plant field. The behaviour of the system in terms of stability, phase space and bifurcation diagrams are considered. The results obtained from different numbers of predators being released are compared. In particular we obtain thresholds of introduced-predator level above which the prey is driven to extinction. Future models will include age-structured multi-compartments for both the prey and predator populations.

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.