Does the pH of the suspension influence the germination of Trichoderma harzianum conidia?

1. Competence Why should we be concerned about education in biological control? It can be argued that most people working with this subject (scientists, extension officers etc.) do not need a particular education, but need solely a strong background in one discipline relevant for their particular approach. For example, scientists can have a background in applied entomology, plant pathology, microbial fermentation or legislation. At many universities worldwide biological control is one among other elements to be taught at courses in applied entomology, plant pathology or weed control. Students are provided with an overview, for example by having a lecture or two on the subject. Such overview lectures are mostly closely related to the application of biological control and can be excellent introductions to the subject. Such introductory lectures will potentially stimulate students to learn much more in depth and thus to obtain real qualifications in biological control. We believe that education at the university level in biological control has not yet reached its potential, but should be devoted much more attention as a subject in its own right. Students should get a chance not only to get a brief overview, but they should be able to understand fully the concept and practical possibilities. Also, we believe that the strict separation between biological control of pest insects, plant diseases and weeds is a hindrance for future scientists and other people involved in the protection of plants and husbandry, to develop a broad perspective on biological control. Therefore, we suggest that education in biological control should be based on a strong, broad view, and that this education should include as much as possible biological control of both pest insects (and other invertebrates), plant diseases and weeds. Education in biological control must be closely linked to the needs of the end-users, but should also include significant aspects of fundamental interest. At the Royal Veterinary and Agricultural University (KVL) in Denmark, overview lectures on biological control have been given for many years. Since 1988 our student have had the opportunity to choose courses devoted solely to biological control and thus to obtain defined competences in biological control. The first course was a laboratory course in biological control of insects, later a laboratory course in biological control of plant diseases and a theoretical lecture course in biological control of insect pests, plant diseases and weeds were added. The following describes the most important experience we have obtained over these years by having laboratory and lecture courses.

Chapter 23 - Binomial effectiveness of chitin nanofibrils on humans and plants

Biological control of plant diseases has emerged as a central pillar of sustainable agriculture in response to the environmental, regulatory, and resistance-related limitations of chemical pesticides. Over the past four decades, advances in microbial ecology, molecular biology, genomics, and formulation technology have transformed biological control from an experimental concept into a viable component of integrated disease management systems. This review synthesises current knowledge on the mechanisms, technologies, applications, and constraints of biological control of plant diseases. Beneficial microorganisms—including bacteria, fungi, actinomycetes, and viruses—are now widely used to suppress soilborne, foliar, and post-harvest pathogens through mechanisms such as antibiosis, competition, mycoparasitism, induced systemic resistance, and microbiome modulation. Recent innovations, including genome-informed strain selection, synthetic microbial consortia, RNA-based biopesticides, and precision delivery systems, have enhanced the consistency and efficacy of biological control agents (BCAs). Despite significant progress, challenges remain, including variable field performance, formulation stability, regulatory complexity, and limited farmer adoption in some regions. Prospects lie in integrating multi-omics tools, artificial intelligence-driven strain discovery, climate-resilient biocontrol strategies, and policy frameworks that encourage commercialisation and adoption. The study explores emerging directions that may redefine plant disease management in the coming decades. The study concludes that its continued advancement and integration into holistic crop management strategies will play a decisive role in shaping resilient and environmentally responsible agricultural systems in the future. Moreover, supportive policy frameworks, sustainability incentives, and carbon-credit initiatives may accelerate adoption by aligning biological control with broader environmental goals.

Biological control of plant diseases is an important component of disease management, particularly in the today’s’ world of environmental consciousness and awareness. It is particularly preferred method of disease management under organic production system. Biological control is successful in almost all the crops against a number of diseases but soil borne diseases are most responsive to bio-control methods. The agents of biological control, known as bio-control agents (BCAs) belong to a vast group of micro-organisms, particularly fungi (Trichoderma, Ampelomyces, etc), bacteria (Pseudomonas, Bacillus, etc) and actinomycetes. Bottle gourd is an important vegetable crop belonging to the family Cucurbitaceae. It suffers from a number of diseases like anthracnose, powdery mildew, downy mildew, wilt, etc. The present review shall be an attempt to review the biological control of the major diseases of bottle gourd.

Biological disease control continues to increase in significance as chemical pesticides are withdrawn and environmental pressures stimulate the search for alternate disease control measures. Consequently, a book that aims to ‘‘act as a catalyst in ushering newer ideas to provide meaningful solutions to intricate problems in plant disease biocontrol technology’’ should be a valuable addition to the literature. Its purported target readership is very wide including ‘‘scholars, scientists, agriculturalists, plant pathologists, administrators and enlightened farmers’’ and so much was expected. The first chapter by Berg is highly focused on the control of soilborne pathogens in strawberries. Perhaps an odd choice when some form of introductory overview of biological control of plant disease may have been expected. Nevertheless, the author skilfully brings in relevant information from other systems to provide a good balanced review of the organisms identified and used for biocontrol in this plant species, particularly the rhizosphere, as well as outlining the screening procedures and application techniques for biological control agents (BCAs) on strawberry. There are then two chapters on the role and use of arbuscular mycorrhizal fungi (AMF) for disease control. Chapter 2 (Demir and Akkopru) has seven pages of background before the main subject is reached and then the rest of the time is spent describing mechanisms of disease biocontrol with AMF. This is odd as the topic of the following Chapter 3 (Sharma et al.) is also concerned with mechanisms of AMF biocontrol. Together the basic concepts associated with the use of AMF fungi for biocontrol of plant diseases are covered but there are few references quoted after 2000 and the information may not be fully up-to-date. I also find it strange that there are two chapters on AMF as biocontrol agents whereas there is no mention in either of these chapters, or elsewhere in the book, concerning the large literature on the use of ectomycorrhizal fungi for control of plant diseases. Chapter 4 (by Rosas) is entitled ‘‘The role of rhizobacteria in biological control of plant disease’’. This topic is enough for a book on its own and, not surprisingly, the review has to focus, and mechanisms involved in rhizobacterial biocontrol is the topic selected. Aspects concerning the role of antibiotics, siderophores, extracellular enzymes and induced resistance are all covered superficially but provide a good basic introduction to the area. The following Chapter 5 is unique in the book in both having the greatest number of authors (13) and a strange combination of part review and part research paper considering bacterial root tip colonisation associated with biological control of tomato foot and root rot. It outlines the procedures used by the team over 15 years of studying the mechanisms associated with J. M. Whipps (&) Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, UK e-mail: John.Whipps@warwick.ac.uk

The controlled environment of greenhouses, the high value of the crops, and the limited number of registered fungicides offer a unique niche for the biological control of plant diseases. During the past ten years, over 80 biocontrol products have been marketed worldwide. A large percentage of these have been developed for greenhouse crops. Products to control soilborne pathogens such as Sclerotinia, Pythium, Rhizoctonia and Fusarium include Coniothyrium minitans, species of Gliocladium, Trichoderma, Streptomyces, and Bacillus, and nonpathogenic Fusarium. Products containing Trichoderma, Ampelomyces quisqualis, Bacillus, and Ulocladium are being developed to control the primary foliar diseases, Botrytis and powdery mildew. The development of Pseudomonas for the control of Pythium diseases in hydroponics and Pseudozyma flocculosa for the control of powdery mildew by two Canadian research programs is presented. In the future, biological control of diseases in greenhouses could predominate over chemical pesticides, in the same way that biological control of greenhouse insects predominates in the United Kingdom. The limitations in formulation, registration, and commercialization are discussed, along with suggested future research priorities.

Navicula arenaria Donkin 1861 is a marine microalga belongs to class of bacillariophycea. Recently, microalgae and their products are used as biological control of diseases caused by phytopathogenic fungi. This is considered environmentally ecofriendly method to overcome the plant damage caused by soil borne pathogenic fungi and thereby economic loss. Therefore, this study aimed to investigate in vitro the antifungal activity of N. arenaria isolate PS 31 extracellular and intracellular metabolites against two taxa of soil borne phytopathogenic fungi; Macrophomina phaseolina and Fusarium oxysporum. N. arenaria PS 31 hexane extract was the most effective extract on growth inhibition of both phytopathogenic fungi. There is no significant difference between miconazole and N. arenaria hexane extract of 5.6 mg/ml on growth inhibition of F. oxysporum. The inhibitory effect of hexane extract at 5.6, 4.2 and 2.8 mg/ml and ethyl acetate extract at 35% (v/v) was higher than controls. Ethyl acetate extract was effective on growth inhibition of M. phaseolina (29.67%). GC-MS analysis of N. arenaria hexane fraction revealed the presence of potent antifungal compounds such as Phenol, 2,2'-methylenebis[6-(1,1-dimethylethyl)-4-methyl-, di-n-octyl phthalate, cholestane-3,5-diol, 5-acetate,(3.beta.,5.alpha.), Cholestan-3-ol,(3.beta.,5.beta.)- and beta.-Sitosterol. These results suggest that N. arenaria hexane extract can be used in biological control of plant diseases caused by M. phaseolina and F. oxysporum.

The Problem of Acquired Physiological Immunity in Plants

In the present study, a deep-sea bacterial strain designated Bacillus sp. strain wsm-1 was screened and found to exhibit strong antifungal activity against many plant-pathogenic fungi, and corresponding antifungal agents were thereby purified and determined by tandem mass spectrometry to be two cyclic lipopeptide homologs. These homologs, which were different from any previously reported lipopeptides, were identified to possess identical amino acid sequences of β-amino fatty acid-Asn-Ser-Asn-Pro-Tyr-Asn-Gln and deduced as two novel lipopeptides designated C14 iturin W and C15 iturin W. Electron microscopy observation indicated that both iturin W homologs caused obvious morphological changes and serious disruption of plasma membrane toward fungal cells, while C15 iturin W exhibited more serious cell damages than C14 iturin W did, which was well consistent with the results of the antifungal activity assays. To improve the yield and antifungal activity of iturin W, the effects of different carbon and nitrogen sources and amino acids on production of C14 iturin W and C15 iturin W were investigated. The results indicated that supplements of most of the detected carbon and nitrogen sources could increase the yield of C14 iturin W, but inhibit the yield of C15 iturin W, while supplements of tryptone and most of the detected amino acids could increase the yield of both C14 iturin W and C15 iturin W.IMPORTANCE Plant disease caused by pathogenic fungi is one of the most devastating diseases, which affects the food safety of the whole world to a great extent. Biological control of plant diseases by microbial natural products is more desirable than traditional chemical control. In this study, we discovered a novel lipopeptide, iturin W, with promising prospects in biological control of plant diseases. Moreover, the effects of different carbon and nitrogen sources and amino acids on production of C14 iturin W and C15 iturin W would provide a reasonable basis for the optimization of the fermentation process of lipopeptides. Notably, the structure of iturin W was different from that of any previously reported lipopeptide, suggesting that deep-sea microorganisms might produce many novel natural products and have significant potential in the development of biological products in the future.

Bacillus species have been employed as biocontrol agents in the context of plant disease management. However, the precise mechanisms through which they function remain to be fully elucidated. Cyclic lipopeptides (cLPs) have been deduced to play key roles in the biological control of plant diseases using Bacillus strains. In the early stages of research, the hypothesis was put forward that cLPs could suppress diseases through their antimicrobial activity. However, recent research provides robust evidence that cLPs function primarily as elicitors by inducing disease resistance in host plants. This review introduces recent trends regarding the characteristics of Bacillus cLPs in the context of biological control against plant diseases.

Microorganisms exert antagonistic effects on pathogens through different mechanisms, thereby achieving biological control of plant diseases. Many Burkholderia strains can produce complex secondary metabolites and substances that have toxic effects on host cells. The phage tail-like bacteriocins (tailocins) is a compound with antibacterial activity. However, its function in B. multivorans has not yet been reported. This article explores the ability of B. multivorans WS-FJ9 to antagonise plant pathogenic fungi and oomycetes, screening the potential tailocins in the strain WS-FJ9 and verifying their function, to reveal its novel antimicrobial mechanisms. We found that WS-FJ9 had strong antagonistic effects on the plant pathogenic fungi Phomopsis macrospore and Sphaeropsis sapinea, and the pathogenic oomycete Phytophthora cinnamomi. The phage tail-like protein Bm_67459 was predicted from the WS-FJ9 strain genome. The Bm_67459 cDNA encoded 111 amino acid sequence, and the relative molecular weight was approximately 11.69 kDa, the theoretical isoelectric point (pI) was 5.49, and it was a hydrophilic protein. Bm_67459 had no transmembrane helix region or signal peptide, and it belonged to the Phage_TAC_7 super family. qRT-PCR results showed that Bm_67459 gene expression was significantly upregulated during contact between WS-FJ9 and P. cinnamomi. The purified Bm_67459 protein significantly inhibited P. cinnamomi mycelial growth at 10 μg·mL-1. In summary, the WS-FJ9 strain had broad-spectrum anti-phytopathogenic activity, and the tailocin Bm_67459 was an important effector against the plant pathogen P. cinnamomi, which helps to reveal the antagonistic mechanism of this strain at the molecular level and provides excellent strain resources for the biological control of plant diseases.

For centuries, microorganisms have served mankind in many ways. Relatively recent developments include the use of bacterial inoculants for bioremediation and agricultural purposes like biological control of plant diseases. Whereas agricultural applications of bacteria have been successful to some extent, improvement of their efficacy is necessary for commercial applications on a large scale. For instance, the remediation of mixed organic and metal-contaminated sites poses problems that may be overcome by introducing metal resistance in the bacteria used for bioremediation. For biological control of plant diseases the efficacy can be improved by combining several mechanisms of antagonism against pathogens in a biocontrol agent. Genetic modification now enables us to construct microbial strains with such novel and enhanced properties. Large-scale introduction of genetically modified strains into the environment poses some challenging questions.

Plant growth promoting rhizobacteria (PGPR) colonizes the root system of plants and can modulate plant growth by enhancing the availability of nutrients and protect the plant from phytopathogens. For a long period, PGPR were mainly used as biofertilizers in agriculture fields. Biological control of plant diseases has emerged as a promising alternative to synthetic pesticides and fungicides. Recently, the application of PGPR has been extended to control several diseases in economically important plants. Numerous unequivocal evidences suggest that PGPR play a key role in the suppression of various plant pathogens by different mechanisms. This review presents the recent advances in our understanding of biological control by PGPR and their interactions with the plant system.

Biological control of plant diseases is important for crop production. Botrytis cinerea and Fusarium graminearum are two common pathogenic fungi which result in great harm to crop production, processing, and storage of foodstuffs. Yeasts have unique advantages to be the focus of biological control of plant diseases through multiple mechanisms, including producing volatile organic compounds (VOCs) with inhibitory effect. However, the discontinuous display of inhibitory effect by yeast VOCs on pathogenic fungi is restricted by the conventional confrontation method, and the inhibitory mechanisms are unclear. We developed a new method to detect the inhibitory effect of Saccharomyces cerevisiae (yeast) VOCs on B. cinerea and F. graminearum. Our results showed that the yeast VOCs inhibited the growth and development of B. cinerea and F. graminearum and the strength of the inhibitory effect is positively related to the yeast inoculation amount. We confirmed the inhibition effect of ethyl acetic, one of the main yeast VOCs, on both pathogenic fungi. We further found that the deletion or overexpression of the ethyl acetic synthesis-related genes (ATF1 and/or ATF2) did not change the inhibitory effect much. The overexpression of ATF1 changed the main composition of VOCs. One of the changed VOCs, phenethyl acetic, even had stronger inhibitory effect than ethyl acetic on F. graminearum when they were added alone. These results suggest that the inhibitory effect of yeast VOCs on pathogenic fungi is a complex module. The lonely added individual component of VOCs may inhibit the growth and development of pathogenic fungi, while the partial alternation of VOC composition through gene modification may not be enough to change the total inhibitory effect.

Research into the biological control of plant diseases has arisen from a need to reduce dependence on chemical pesticides whose misuse in many crop systems has led to negative effects on the environment and health. Moreover, the use of chemical pesticides and fungicides is a relatively short term measure. On the other hand biological control of plant diseases offers an answer to many persistent problems in agriculture including problems of resource limitation, non-sustainable agricultural systems and over-reliance on pesticides (Cook and Baker, 1983). Bioprotectants provide unique opportunities for crop protection because they grow and proliferate and can colonize and protect newly formed plant parts to which they were not initially applied (Harman, 1990).