Fungi as biological control agents of arthropods of agricultural and medical importance

Parasitology ◽  
1982 ◽  
Vol 84 (4) ◽  
pp. 205-240 ◽  
Author(s):  
R. A. Hall ◽  
B. Papierok

SUMMARYThere are many species of fungi attacking terrestrial and aquatic insects of agricultural and medical importance. Of these, few species have received much attention with a view to their use as biological control agents. The mechanisms of infection have been comparatively well studied, although many questions remain to be answered. The knowledge so far obtained has shed some light on the reasons for host specificity. Temperature, above all relative humidity, and their interactions are the most important physical factors influencing infection of terrestrial insects by entomopathogenic fungi and these are discussed in relation to epizootiological events. In aquatic environments, temperature, salinity and organic pollution are the important factors. In addition to these physical factors, numerous biotic factors at the level of the insect and the fungal pathogen influence both infection and spread of disease in insect populations. The complexity of the interactions of the biotic and abiotic factors makes it extremely difficult to study the influence of any one of these. Virulence of fungal pathogens and its measurement are discussed, together with the shortcomings of present bioassay systems; virtually no laboratory bioassay system exists which has been designed to yield data meaningful in the field. Mass-production techniques are described as are their inherent problems and those of formulation and storage. Finally, the achievements of fungal control of insects in the field are reviewed. Thus far, several species are mass-produced and are in widespread use, two of which,Verticillium lecaniiandHirsutella thompsonii, have been commercialized. More studies, ecological, fundamental and developmental are required in this field to realize fully the potential of other candidate fungi.

2011 ◽  
Vol 4 (3) ◽  
pp. 332-340 ◽  
Author(s):  
Kimberly K. Crider

AbstractQuantification of interference with biological control agents can provide support for anecdotal claims of success or failure of agent establishment and efficacy. This study was initiated because of observed predation of cinnabar moth larvae by carpenter ants when releasing larvae for the control of tansy ragwort, an invasive plant in Montana. Biotic and abiotic factors were compared among three sites with historically variable moth population establishment. Two experiments were developed to (1) observe and document insect activity, predation, or disappearance on tansy ragwort stems either protected or accessible to ants; and (2) quantify the effects of ant exclusion on herbivory of tansy ragwort. Site comparisons indicated that ant colony density was highest at the driest of three sites, and, interestingly, no ant colonies were detected at the site with higher observed numbers of moth larvae and adults and lower densities of tansy ragwort. Available substrate (logs and stumps) for ant colonization did not differ between the three sites. In the ant exclusion experiments, a larger number of larvae were missing on plants accessible to ants (63%) compared with plants where ants were excluded (39%) after 36 h. Direct observation of predation of larvae by carpenter ants accounted for 9% of missing larvae on stems accessible to ants. Larvae were able to consume 81% of original flowers or buds on ant-excluded stems, compared with 18% consumption on ant-accessible stems, suggesting that ant predation could limit the efficacy of cinnabar moth larvae. These results provide one of many possible explanations for the anecdotal observations of large, persistent populations of cinnabar moths in moist areas. This work emphasizes the importance of post-release observation and monitoring to detect and, ideally, quantify factors to support anecdotal perceptions regarding the fate and subsequent efficacy of insect biological-control agents.


2005 ◽  
Vol 19 (1) ◽  
pp. 19-26 ◽  
Author(s):  
CAMILLA B. YANDOC ◽  
RAGHAVAN CHARUDATTAN ◽  
DONN G. SHILLING

2020 ◽  
Author(s):  
Senlin Liu ◽  
Muzammil Hassan Khan ◽  
Zhongyuan Yuan ◽  
Sarfraz Hussain ◽  
Hui Cao ◽  
...  

AbstractContinuous cropping always leads to severe abiotic and biotic problems, especially the high-intensity land utilization in greenhouses, which causes widespread concern. Effective Microorganisms (EM) and Bacillus subtilis (BS) have been widely used to promote plant growth and increase yields as biological control agents (BCAs). However, their effects on soil microbes are obscure. To regulate the microbial community in continuous cropping strawberry soils, we developed four soil amendments by combining EM and BS with compost. The amplicon sequencing of bacterial and fungal ribosomal markers was applied to study the response of the soil microbiome structure. We noticed a sharp increase in bacterial diversity after the addition of EM-treated high compost and BS-treated low compost, while there was no significant change in fungal diversity among treatments. Interestingly, both the relative abundance and FUNGuild predictions was consistent in revealing that BCAs may inhibit fungal pathogens in soils. Correlation analysis indicated that soil microbial community was indirectly driven by soil properties. Co-occurrence networks demonstrated that BCAs could be microecologically homogeneous through enhancing bacterial network complexity and modularity. Collectively, EM-treated high compost and BS-treated low compost can well regulate the microbial community structure and thus maintain soil health.


Author(s):  
Anahi A Barrera-López ◽  
Ariel W Guzmán-Franco ◽  
Materesa Santillán-Galicia ◽  
Fernando Tamayo-Mejía ◽  
Rafael Bujanos-Muñiz ◽  
...  

Abstract Bagrada hilaris Burmeister (Hemiptera: Pentatomidae) is a pest of Palearctic origin. Its presence in the United States was first reported in 2008 and in Mexico in 2014; it affects brassica crops. There are practically no reports of natural enemies of B. hilaris in America. Entomopathogenic fungi are strong candidates for microbial control of this pest. Evaluating the susceptibility of this pest to fungi that are native to the region where they will be used is a sensible first step to finding candidate biological control agents. The aim of our research was to select potential microbial agents to control B. hilaris. Eleven isolates of Beauveria bassiana, Beauveria pseudobassiana, Metarhizium anisopliae, and Isaria fumosorosea were evaluated to determine the susceptibility of B. hilaris. Isolates of B. bassiana caused the highest mortality due to infection (100%) compared with the other isolates. The I. fumosorosea isolate caused the lowest percent mortality (56%). The two B. bassiana isolates Bb88 and AP3 were more virulent than M. anisopliae isolate Ma129. The sex of the insect had no effect on infection levels achieved by B. bassiana isolates Bb88 and AP3. The results of our study contribute valuable information for the development of fungal species with potential to manage B. hilaris populations. Field studies are the next step in order to develop these isolates as biological control agents of B. hilaris.


2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen

SummaryGrapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture worldwide causing a significant reduction of both yields and quality of grapes. Biological control presents a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from a variety of grapevine tissues, including sap, cane and pith and evaluate their antagonistic activity against selected fungal pathogens responsible for GTDs in vitro. Bacterial and fungal isolates were preliminary screened in vitro to determine their antifungal activity via a dual culture assay against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited E. lata mycelial growth up to 64% and N. parvum mycelial growth up to 73% with overgrowth and stopped growth being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited E. lata mycelial growth up to 20% and N. parvum mycelial growth up to 40%. Select antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subject to further dual culture antifungal analysis against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analysis revealed that these Trichoderma isolates resulted significantly inhibited mycelial growth of N. parvum, E. lata and D. ampelina causing up to 20.11%, 60.55% and 70.9% inhibition respectively (P≤0.05). Multilocus sequence analysis revealed that the Trichoderma isolates are most closely related to Trichoderma asperellum and Trichoderma hamatum. This study identifies grapevine sap as a novel source of potential biological control agents for control of GTDs to support existing efforts to control GTDs. Further testing will be necessary to fully characterize these microbes mode of antagonism and assess their efficacy for pruning wound protection in planta.


HortScience ◽  
2020 ◽  
Vol 55 (7) ◽  
pp. 988-994
Author(s):  
Jacqueline Joshua ◽  
Margaret T. Mmbaga

Fungi isolated from snap bean roots and rhizosphere soil where fungicides are not used included Fusarium oxysporum, Fusarium equiseti, Fusarium subglutinans, Fusarium camptoceras, Fusarium chlamydosporum, Fusarium verticillioides, Fusarium proliferatum, Fusarium acuminatum, Fusarium solani, Peyronellaea pinodella, Macrophomina phaseolina, and Glomerella guttata. Only P. pinodella, M. phaseolina, and F. oxysporum were isolated on symptomatic plants. These soilborne fungi are common pathogens of diverse host plants. Pathogenicity tests under controlled environment demonstrated that these fungi were pathogenic on snap beans. Subsequently, bacterial endophytes isolated from snap bean roots, papaya roots and stems, and dogwood stems were evaluated as potential biological control agents against these diverse fungi. All bacteria isolated, including Bacillus vallismortis (PS), Bacillus amyloliquefaciens (Psl), Bacillus subtilis (Prt), Bacillus thuringiensis (Y and IMC8), Enterobacter sp. (E), Stenotrophomonas sp. (B17A), and Serratia sp. (B17B) suppressed growth of the fungal pathogens in vitro and formed clear inhibition zones in petri dish dual cultures. Growth media taken from the inhibition zones suppressed growth of the fungal pathogens in the absence of the bacterial cells, suggesting that the bacteria released unidentified antagonistic biochemical substances into the media. This study constitutes an initial screening of endophytes as biological control agents against diverse fungal pathogens and forms a basis for the discovery of novel strains that can be further developed and integrated into disease management systems for diverse fungal pathogens. Isolates B. vallismortis (PS), B. amyloliquefaciens (Psl), B. subtilis (Prt), and B. thuringiensis (Y IMC8) exhibited the best performance as potential biological control agents paving the way for larger-scale in vivo studies and characterization of their interactions with fungal pathogens.


2016 ◽  
Vol 69 ◽  
pp. 78-85 ◽  
Author(s):  
N. Cripps-Guazzone ◽  
E.E. Jones ◽  
L.M. Condron ◽  
K.L. McLean ◽  
A. Stewart ◽  
...  

The colonisation of plant roots by biological control agents is dependent on abiotic factors one of the most important being soil pH The rhizosphere and endophytic colonisation of ryegrass and sweet corn roots by the biological control agent Trichoderma atroviride LU132 were assessed in a pot experiment with nonsterile soil at three different pHs (55 65 and 75) T atroviride LU132 colonised the roots of both plants regardless of the soil pH with 113147 x 106 CFU/g of dry rhizosphere soil (DRS) for ryegrass and 136350x105 CFU/g DRS for sweet corn T atroviride LU132 was able to colonise both plants endophytically regardless of soil pH However the isolate was recovered from entire ryegrass roots but only from the upper parts of sweet corn roots These experiments demonstrated that T atroviride LU132 colonised the rhizosphere and roots within a soil pH range common to most NZ soils which is a desirable trait for biological control agents


1997 ◽  
Vol 63 (5) ◽  
pp. 366-372 ◽  
Author(s):  
Hiroshi TSUKAMOTO ◽  
Masatoshi GOHBARA ◽  
Mitsuya TSUDA ◽  
Takane FUJIMORI

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