scholarly journals BIOLOGICAL CONTROL OF MELOIDOGYNE JAVANICA AND RHIZOCTONIA SOLANI ON SOYBEAN BY FORMULATION OF BACILLUS THURINGIENSIS AND TRICHODERMA HARZIANUM

2006 ◽  
Vol 14 (1) ◽  
pp. 411-423
Author(s):  
M.E Mahdy ◽  
E.Z Khalifa ◽  
Rania Z. El-Shennawy
2001 ◽  
Vol 91 (7) ◽  
pp. 687-693 ◽  
Author(s):  
E. Sharon ◽  
M. Bar-Eyal ◽  
I. Chet ◽  
A. Herrera-Estrella ◽  
O. Kleifeld ◽  
...  

The fungal biocontrol agent, Trichoderma harzianum, was evaluated for its potential to control the root-knot nematode Meloidogyne javanica. In greenhouse experiments, root galling was reduced and top fresh weight increased in nematode-infected tomatoes following soil pretreatment with Trichoderma peat-bran preparations. The use of a proteinase Prb1-transformed line (P-2) that contains multiple copies of this gene improved biocontrol activity in the greenhouse experiments compared with the nontransformed wild-type strain (WT). All the Trichoderma strains showed the ability to colonize M. javanica-separated eggs and second-stage juveniles (J2) in sterile in vitro assays, whereas P-2 also penetrated the egg masses. This protease-transformed line presented the same nematicidal and overall proteolytic activity as the WT in in vitro tests in which concentrated soil extracts from Trichoderma-treated soils immobilized the infective J2. However, the J2 immobilization and proteolytic activities of both P-2 and the WT were higher than those obtained with strain T-203. Characterization of the activity of all Trichoderma strains soil extracts on J2 showed that it was heat resistant and restricted to the low-molecular-weight fraction (less than 3 kDa). It is suggested that improved proteolytic activity of the antagonist may be important for the biological control of the nematodes.


2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Mapula T.P. Hlokwe ◽  
Mapotso Kena ◽  
David N. Mamphiswana

Seedling production under smallholder farming systems can be negatively affected by both abiotic and biotic factors. Seedling damping-off caused by Rhizoctonia solani is one of the major biotic factors which causes significant yield reduction. Management is mainly based on the application of synthetic fungicides and cultural practices. However, both methods have limitations which result in their inefficiency. Several studies have reported on the use of plant extracts and biological control to manage plant diseases. The aim of this study was to formulate an effective and practical approach to manage tomato seedling dampingoff using extracts of Monsonia burkeana and Moringa oleifera and a biological control agent Trichoderma harzianum. The efficacy of both extracts was investigated under laboratory conditions to determine the most suppressive concentration to R. solani growth. Methanolic extracts from both plants significantly suppressed pathogen growth at different concentrations. M. burkeana significantly reduced R. solani growth at 8 g/mL (71%) relative to control whilst Moringa oleifera extract reduced pathogen growth by 60% at a concentration of 6 g/mL. The highest suppressive concentrations were further evaluated under greenhouse conditions to test their efficacy on seedling damping-off. In damping-off treatments, both plant extracts and T. harzianum also significantly reduced (p=0.5) pre- and post-emergence dampingoff incidence. M. burkeana recorded the highest suppression at 78%, followed by M. oleifera at 64%. Trichoderma harzianum reduced incidence of damping-off by 60% and this was higher than both plant extract treatments.


Author(s):  
Jaime Montealegre ◽  
Luis Valderrama ◽  
Soledad Sánchez ◽  
Rodrigo Herrera ◽  
Ximena Besoain ◽  
...  

2019 ◽  
Vol 42 (4) ◽  
pp. 38-43
Author(s):  
Magdalena Matić ◽  
Tamara Siber

Zbog stalnog povećanja upotrebe kemijskih pesticida i njihovog štetnog djelovanja na ljudsko zdravlje i okoliš, sve veće zanimanje pobuđuju metode biološke kontrole uzročnika biljnih bolesti. Biološka kontrola je mjera koja podrazumijeva korištenje mikroorganizama koji smanjuju populaciju štetnika i patogena i na taj način štite biljku i kontroliraju razvoj bolesti. U Hrvatskoj je trenutno na tržištu prisutan samo jedan biofungicid, na bazi bakterije iz roda Pseudomonas, za suzbijanje uzročnika bijele noge (Rhizoctonia solani) na krumpiru, batatu, čičoki i kineskom jamu te uzročnika srebrolikosti gomolja (Helminthosporium solani) na krumpiru. Vrste Bacillus thuringiensis, Bacillus subtilis i Pseudomonas fluorescens su najvažniji predstavnici bakterija uključenih u biokontrolu protiv uzročnika biljnih bolesti. Do danas je na svjetskom tržištu prisutno ili je u procesu registracije 28 sredstava na bazi različitih vrsta roda Trichoderma, koji većinom djeluju protiv fitopatogenih gljiva iz rodova Pythium, Rhizoctonia i Fusarium. Najzastupljenije vrste roda Trichoderma koje se koriste u biološkoj kontroli su Trichoderma harzianum, Trichoderma viride i Trichoderma koningii. Upotreba antagonističkih gljiva i bakterija u biološkoj kontroli brojnih uzročnika bolesti predstavlja važnu alternativu kojom bi se mogli zamijeniti kemijski pesticidi ili u što većoj mjeri smanjiti njihova primjena. Cilj rada je prikazati antagonističke gljive i bakterije koje se koriste u biološkoj kontroli te opisati njihove složene mehanizme djelovanja.


2021 ◽  
Vol 735 (1) ◽  
pp. 012079
Author(s):  
Muneer Saeed M. Al-Baldawy ◽  
Ahed A A H Matloob ◽  
Mohammed K. N. Almammory

1987 ◽  
Vol 33 (10) ◽  
pp. 850-856 ◽  
Author(s):  
G. Vannacci ◽  
G. E. Harman

Forty-two microorganisms were tested as biological control agents against Alternaria raphani and A. brassicicola. Tests were conducted for in vitro antagonistic ability, for ability to control the pathogens on naturally infected seeds germinated on moistened blotters, and in planting mix in growth chamber studies, and for their ability to reduce pod infection. The organisms tested were obtained from cruciferous seeds or were strains already identified as being effective against soil-borne Pythium species. The blotter test indicated that six organisms increased both the number of healthy seedlings and the number of seedlings produced from A. raphani infected radish seeds. An additional seven strains improved either germination or increased the number of healthy seedlings. Twenty-nine organisms increased the number of healthy cabbage seedlings from A. brassicicola infected seeds, but total germination was not modified by any treatment. Experiments in planting mix showed that five antagonists (Chaetomium globosum, two strains of Trichoderma harzianum, T. koningii, and Fusarium sp.) increased the number of healthy plants in both radish samples tested, while four additional antagonists provided a significant increase in only one of the samples tested. The five antagonists that consistently increased numbers of healthy radish seedlings also decreased pod infection by A. raphani. None were as effective as iprodrone, however. Several effective antagonists were found to be mycoparasitic against Alternaria spp. Some strains of Trichoderma previously found to be effective against Pythium spp. were also effective against Alternaria spp., indicating that these strains have a wide host range.


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