Selection and characterization of twoBacillus thuringiensisstrains showing nematicidal activity againstCaenorhabditis elegansandMeloidogyne incognita

2021 ◽  
Vol 368 (5) ◽  
Author(s):  
Luis A Verduzco-Rosas ◽  
Rosalina García-Suárez ◽  
José J López-Tlacomulco ◽  
Jorge E Ibarra

AbstractBacillus thuringiensis has been widely used as a biological control agent against insect pests. Additionally, nematicidal strains have been under investigation. In this report, 310 native strains of B. thuringiensis against Caenorhabditis elegans were tested. Only the LBIT-596 and LBIT-107 strains showed significant mortality. LC50s of spore-crystal complexes were estimated at 37.18 and 31.89 μg/mL for LBIT-596 and LBIT-107 strains, respectively, while LC50s of partially purified crystals was estimated at 23.76 and 20.25 μg/mL for LBIT-596 and LBIT-107, respectively. The flagellin gene sequence and plasmid patterns indicated that LBIT-596 and LBIT-107 are not related to each other. Sequences from internal regions of a cry5B and a cyt1A genes were found in the LBIT-596 strain, while a cry21A, a cry14A and a cyt1A genes were found in the LBIT-107 strain. Genome sequence of the LBIT-107 strain showed new cry genes, along with other virulence factors, hence, total nematicidal activity of the LBIT-107 strain may be the result of a multifactorial effect. The highlight of this contribution is that translocation of spore-crystal suspensions of LBIT-107 into tomato plants inoculated at their rhizosphere decreased up to 90% the number of galls of Meloidogyne incognita, perhaps the most important nematode pest in the world.

2021 ◽  
Vol 11 (9) ◽  
pp. 4066
Author(s):  
Spiridon Mantzoukas ◽  
Ioannis Lagogiannis ◽  
Aristeidis Ntoukas ◽  
George T. Tziros ◽  
Konstantinos Poulas ◽  
...  

Gnomoniopsis castaneae is the cause of the chestnut brown rot but has been also regarded as an important mortality factor for the chestnut gall wasp Dryocosmus kuriphilus. The question to whether G. castaneae could serve as a natural biocontrol agent against insect pests is investigated in the present study. We used three serious insect pests as experimental model insects: Plodia interpuctella and Trogoderma granarium, which are important pests of stored products, and Myzus persicae, a cosmopolitan, serious pest of annual and perennial crop plants. Although chemical pesticides represent effective control means, they are also related to several environmental and health risks. In search for alternative pest management methods, scientific interest has been focused, inter alia, on the use of entomopathogenic fungi. While Isaria fumosorosea has long been recognized as an effective control agent against several pests, G.castaneae has been very little studied. The present study examined whether and to what extent G. castaneae and I. fumosorosea exhibit insecticidal activity against fourth-instar larvae of P. interpunctella and T. granarium and adults of M. persicae. Mortality was examined in interrelation with dosage and time exposure intervals. Both fungi exhibited pesticidal action. However, G. castaneae induced noteworthy mortality only at very high doses. In general, we concluded that G. castaneae failed to cause high insect pathogenicity at normal doses and may not be an efficient biocontrol agent compared with other entomopathogens. On the other hand, our study reiterates the pathogenic potential of I. fumosorosea. More studies are needed to further our insight into the potential of EF species as a component of IPM.


2011 ◽  
Vol 43 (2) ◽  
pp. 269
Author(s):  
Behzad Habibpour ◽  
Amir Cheraghi ◽  
Mohammad Saeed Mossadegh

This article is the first report on the promising effect of an entomopathogenic fungus, <em>Metarhizium anisopliae</em> (Metschnikoff) Sorokin to control populations of <em>Microcerotermes diversus </em>Silvestri. Biological control is an alternative to the long-term usage of chemical pesticides.<em> M. anisopliae</em>, the causal agent of green muscardine disease of insects, is an important fungus in biological control of insect pests. Bait systems can eliminate entire colonies of subterranean termites. Baiting reduces adverse environmental impacts caused by organochlorine and organophosphate pesticides in the control of termites and creates sustainable protection of buildings against their invasion. Treated-sawdust bait was applied by two methods: a) combination of treated sawdust and untreated filter paper, and b) combination of treated sawdust and untreated sawdust. When combinations of treated sawdust and untreated sawdust were used, LC50 and LC90 were 8.4&times;106 and 3.9&times;107 (spore/ml), respectively. With the use of improved bait formula and more virulent strains, we hope to achieve better control of termite colonies and enable pathogens to become a useful element in the Integrated Pest Management system.


2015 ◽  
Vol 55 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Keivan Karimi ◽  
Mahdi Arzanlou ◽  
Asadollah Babai Ahari ◽  
Mostafa Mansour Ghazi

AbstractWe report the first case of chafer beetle [Anisoplia austriaca(Herbst 1783)] mortality caused byActinomucor elegansvar.elegansin wheat fields of the Kurdistan province, Iran. For three years, dead larvae ofAnisoplia austriacawere collected from wheat fields of the Kurdistan province. Similar isolates of a fast-growing fungus were recovered from all samples. The fungal isolates were identified asA. elegansvar.elegansbased on morphological and cultural characteristics. The identity of the species was further confirmed using sequence data of the ITS (Internal Transcribed Spacer) region of ribosomal DNA. Koch’s postulates were fulfilled by the inoculation of the larvae ofA. austriacaandGalleria mellonella(Linnaeus, 1758) (as the model insect) using the spore suspension ofA. elegansvar.elegans. The viability of sporangiospores was evaluated using a spore dilution technique on germination medium. The results on the pathogenicity (100% mortality inA. austriacalarvae) and viability tests (germination: 95.45%) demonstrated thatA. elegansvar.eleganscan be considered as a potential biocontrol agent against the chafer beetle. Field experiments are still required to evaluate the capacity ofA. elegansas a biological control agent.


2021 ◽  
Vol 13 (2) ◽  
pp. 237-242
Author(s):  
Dyah Rini Indriyanti ◽  
Siti Harnina Bintari ◽  
Ning Setiati ◽  
Jamil Maulana Zahriyan Alfiyan

Metarhizium anisopliae is a parasitic fungus on insects, and thus called entomopathogenic fungus. This fungus is used as a biological control agent for insect pests. Fungal propagation can be done using a variety of media. The purpose of this study was to analyze the growth of M. anisopliae on four types of media, with conidial density and viability as the growth parameters. This research was conducted at the Laboratory of Microbiology, Universitas Negeri Semarang. This study was an experimental research used a Completely Randomized Design (CRD) with one factor and four treatments: Control (PDA/Potato Dextrose Agar medium), Treatment I (ELSA/Extract Larvae Sucrose Agar medium), Treatment II (CWSA/Coconut Water Sucrose Agar medium), Treatment III (CWELSA/Coconut Water and Extract Larvae Sucrose Agar medium). The and results showed that there was an effect of growth media on the density and viability of M. anisopliae conidia. CWELSA media had the highest conidial density (2.91 x 108 cfu/mL) and viability (97.17%). CWSA media had  2.82 x 108 cfu/mL and 95.33%. PDA media had 2.25 x 108 cfu/mL and 92.83%. ELSA media had 1.64 x 108 cfu/mL and 90.83%. The high conidial density and viability of M. anisopliae is CWELSA  medium. This study is as an alternative growth medium to improve the quality of M. anisopliae propagation.


1993 ◽  
Vol 59 (12) ◽  
pp. 4189-4197 ◽  
Author(s):  
Joyce E. Loper ◽  
Carol A. Ishimaru ◽  
Susan R. Carnegie ◽  
Apichart Vanavichit

Nematology ◽  
2017 ◽  
Vol 19 (9) ◽  
pp. 1035-1050 ◽  
Author(s):  
Annika Pieterse ◽  
Louwrens R. Tiedt ◽  
Antoinette P. Malan ◽  
Jenna L. Ross

Worldwide interest in Phasmarhabditis originates from the successful commercialisation of P. hermaphrodita as a biological control agent against molluscs in Europe. To date, P. hermaphrodita has not been isolated from South Africa and, therefore, the formulated product may not be sold locally. During a survey for mollusc-associated nematodes, P. papillosa was dissected from the slug, Deroceras reticulatum, collected from George, South Africa. The nematode was identified using a combination of morphological, morphometric, molecular and phylogenetic techniques. Virulence tests were conducted which demonstrated that P. papillosa caused significant mortality to the European invasive slug Deroceras panormitanum. Additional data are provided in the morphometrics of the infective juvenile and in the molecular identification, using the mitochondrial cytochrome c oxidase subunit I (cox1) gene. This is the first report of P. papillosa from the African continent and of its virulence against D. panormitanum.


1985 ◽  
Vol 117 (4) ◽  
pp. 401-407 ◽  
Author(s):  
O. N. Morris

AbstractThe susceptibility of 31 species of agricultural insect pests representing 7 families of Lepidoptera, 3 of Diptera, and 3 of Coleoptera to the entomogenous nematodes Steinernema feltiae Filipjev and Heterorhabditis bacteriophora Poinar, were investigated in the laboratory. Of the 27 species found susceptible to S. feltiae, 19 are reported for the first time. Of the 21 species killed by H. bacteriophora, 15 are reported for the first time. The Lepidoptera as a group were highly susceptible to the nematodes. On the basis of larval mortality caused by the nematodes, of nematode reproduction in insect cadavers, and of the known economic importance and life histories of the test insects, S. feltiae was judged to warrant further research as a possible biological-control agent against Euxoa ochrogaster (Guenée), E. auxiliaris (Grote), Agrotis orthogonia (Morr.), Actebia fennica (Tauscher), Mamestra configurata Walker, Delia radicum (L.), D. antiqua (Meig.), and Zygogramma exclamationis (F.).


Sign in / Sign up

Export Citation Format

Share Document