scholarly journals Biocontrol of Pythium Damping-Off on Pepper (Capsicum Annuum) with Selected Fungal and Rhizobacterial Agents

2020 ◽  
Vol 9 (1) ◽  
pp. 29-42
Author(s):  
Sabrine Mannai ◽  
Hayfa Jabnoun-Khiareddine ◽  
Bouzid Nasraoui ◽  
Mejda Daami-Remadi

Pythium ultimum is a common soilborne pathogen causing serious losses of pepper seedlings in nurseries and few weeks post-planting. Two pepper associated-P. ultimum isolates (P1 and P2) were shown pathogenic to pepper cv. Altar causing post-emergence damping-off with P2 isolate being the most aggressive. Fungal and bacterial antagonists have been evaluated in vitro and in vivo for their ability to suppress P. ultimum. In dual culture assay, Trichoderma harzianum, T. viride and Gliocladium virens inhibited pathogen radial growth by 18.54, 17.52 and 15.24%, respectively, relative to control, while none of the tested bacteria was shown able to significantly inhibit pathogen growth. However, drastic changes in pathogen hyphae expressed as strong lysis, the formation of mycelial cords and mycoparasitism have been observed. Pepper seeds treated with fungal antagonists’ conidial suspensions showed 60, 50 and 60% less pre-emergence damping-off infections, respectively, compared to the positive control. When tested as root dipping, only G. virens resulted in 40% reduced post-emergence damping-off. An improved seedlings fresh weight, by 79.31 and 76%, was respectively induced by G. virens-, and T. viride-based treatments while an increment of 27.58, 25.33 and 22.22 % was recorded following treatments with G. virens, T. viride and T. harzianum, relative to the positive control. The majority of tested bacterial isolates, applied as a seed treatment, had significantly improved the emergence percentage of inoculated seedlings as compared to control with Burkholderia glathei isolate 35 being the most efficient. When applied as root dipping, reduction of post-emergence damping-off ranged between 40 and 100% with Pseudomonas aureofaciens isolate 314 being the most effective agent. Seedlings treated with P. aureofaciens (314) and Bacillus pumilus (420) showed 35.38 and 28.51% higher heights, respectively. Plant weight was enhanced by 73.06, 61.18, 77.39, 61.8 and 67.93% over control following treatments with P. aureofaciens isolates 314 and 31, Bacillus pumilus 420, P. fluorescens and P. putida 227.

2017 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Tatsuya Ohike ◽  
Minori Maeda ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
...  

Rhizoctonia solani is fungal plant pathogen that infects many different host plants. Recently, biological control agents that are friendly to the environment and ecosystems have attracted much attention as an alternative to the use of chemical fungicide which have been used worldwide to control soil borne pathogens including R. solani. In this study, 53 strains of actinomycetes isolated from environmental soils, and antifungal activities of them were assessed by the dual culture assay. Strain KT showed strong inhibitory activities against 8 phytopathogenic fungi. A great suppressive effect on R. solani growth was observed in the inoculation test of plants using cucumber and chin-geng-sai. In addition, infection of Bipolaris oryzae also could be suppressed in the detached leaf assay using oats. As a result of genetic analysis, it was shown that KT was a species closely related to Streptomyces lavenduligriseus NRRL B-3173T. However, as far as we know, there is no report for biological control agents using S. lavenduligriseus. This study suggests that the strain KT may useful as biological control agents to suppress various crop diseases.


2017 ◽  
Vol 47 (1) ◽  
pp. 102-109
Author(s):  
Alexandre Dinnys Roese ◽  
Gloria Soriano Vidal ◽  
Erica Camila Zielinski ◽  
Louise Larissa May De Mio

ABSTRACT Trichoderma is a biological control agent used to improve the resistance to diseases, which may also estimulate plant growth. Commercial products with Trichoderma are available in different countries, but most of them are based on conidial suspension. This study aimed at evaluating the efficiency of native Trichoderma populations collected from different production systems and applied to the soil by using two methods: conidial suspension and inoculated oat grains. The efficiency of native Trichoderma populations collected from conventional crop and agropastoral and agrosilvopastoral systems in a long-term field experiment was evaluated. The populations efficiencies were evaluated by in vivo tests that assessed the control of soybean damping-off caused by Rhizoctonia solani, plant height and soil colonization with the antagonist. In vitro tests, such as dual culture and assessment of volatile and non-volatile compounds, were conducted to study the mode of action of the populations. Some native Trichoderma populations were as efficient as those from a commercial product in all tests. Compared to conidial suspension, Trichoderma spp. inoculated through oat grains promoted a greater damping-off control, higher plants and more colony-forming units per gram of soil after 3 months of application. Native populations performed equally well or even better than the commercial strain, and the use of a substrate that supports the Trichoderma growth was more efficient than the conidial suspension method.


2021 ◽  
Vol 1044 ◽  
pp. 91-102
Author(s):  
Hersanti ◽  
Lilian Rizkie ◽  
Santi Suryani ◽  
Luciana Djaya ◽  
I Made Joni

This paper reports the performance of a graphite and silica nanoparticles-based delivery system for T. harzianum in controlling the in vitro growth of R. solani and damping-off disease on tomato plants. The in vitro and in vivo experiments were arranged in the randomized complete block design. The in vitro treatment was a dual culture of R. solani and T. harzianum in the various components of formulation on PDA, i.e., T. harzianum + 5 wt.% graphite, T. harzianum + 1wt.% silica NPs., T. harzianum + 5 wt.% graphite + 1 wt.% silica nanoparticles, T. harzianum, 5 wt.% graphite, 1 wt.% silica nanoparticles, fungicide (mancozeb), and a control. The in vivo treatment included the application of T. harzianum in the same compositions as the in vitro treatment, except that there were two controls i.e., inoculated and noninoculated tomato plants with R. solani. T. harzianum by soaking tomato seeds in the formulation suspensions before planting. The results showed that all formulation compositions were able to inhibit the in vitro growth of R. solani. The inhibitions of the colony growth of R. solani caused by formulated and non-formulated T. harzianum were the same. This proved that graphite and silica NPs did not resist to the ability of T. harzianum in controlling R. solani, indicated that the formulation was promising to develop. However, the inhibition of damping-off disease incidence on tomato plants caused by formulated T. harzianum was the same as the non-formulated one only on day 7 after treatments. On days 14, 21, and 28, the inhibitions were lower than the non-formulated ones. It was suggested to reapply the formulation of T. harzianum in the soil at planting and several days after.


Dose-Response ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 155932582096034
Author(s):  
Rizwan Asif ◽  
Muhammad Hussnain Siddique ◽  
Shahbaz Ahmad Zakki ◽  
Muhammad Hidayat Rasool ◽  
Muhammad Waseem ◽  
...  

Cotton ( Gossypium hirsutum) wilt is one of the destructive disease caused by Fusarium oxysporum f. sp. vasinfectum and lead to 100% yield loss under favorable conditions. This study aims to estimate the potential of biological control agents Saccharothrix algeriensis NRRL B-24137 (SA) and chemical fungicides against cotton wilt pathogen under in-vitro and in-vivo conditions. The in-vitro study revealed that carbendazim showed maximum mycelia growth inhibition with a mean of 91% over control, which was further validated in glasshouse assay. In-vitro dual culture test of biocontrol agents with F. oxysporum determined that SA had a potential to inhibit mycelia growth by 68% compared to control. Further in glasshouse assay, the combination of the SA and carbendazim (10 µg/mL) showed a significant ( p < 0.05) disease control. Moreover, results demonstrated that carbendazim and SA remarkably decreased the disease development up to 83% and subsequently, significant improvement was observed in the plant growth parameters (plant length, root length, and plant weight) compared to untreated plants. Conclusively, exploration and utilization of bioagent for fungal diseases in cotton may provide a better line with maximum efficacy and with lesser adverse effects, which will pave a way toward better consequences in fungal treatments.


Plant Disease ◽  
2007 ◽  
Vol 91 (2) ◽  
pp. 220-225 ◽  
Author(s):  
E. Grimme ◽  
N. K. Zidack ◽  
R. A. Sikora ◽  
G. A. Strobel ◽  
B. J. Jacobsen

A biorational synthetic mixture of organic components mimicking key antimicrobial gases produced by Muscodor albus was equivalent to the use of live M. albus for control of seedling diseases of sugar beet (Beta vulgaris) caused by Pythium ultimum, Rhizoctonia solani AG 2-2, and Aphanomyces cochlioides. The biorational mixture provided better control than the live M. albus formulation for control of root-knot nematode, Meloidogyne incognita, on tomato (Lycopersicon esculentum). The biorational mixture provided control of damping-off equal to a starch-based formulation of the live fungus for all three sugar beet pathogens, and significantly reduced the number of root-knot galls on tomato roots compared with a barley-based formulation. Rate studies with the biorational mixture showed that 2 and 0.75 µl/cm3 of soil were required to provide optimal control of Rhizoctonia and Pythium damping-off of sugar beet, respectively. Five microliters of biorational mixture per milliliter of water was required for 100% mortality in 24 h for Meloidogyne incognita in in vitro studies. In in vivo studies, 1.67 µl of the biorational mixture/cm3 of sand resulted in fewer root-knot galls than a Muscodor albus infested ground barley formulation applied at 5 g/liter of sand.


Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 169
Author(s):  
Alessandra Di Francesco ◽  
Michele Di Foggia ◽  
Alessio Vittoria ◽  
Elena Baraldi

Cadophora luteo-olivacea represents a critical problem for kiwifruit in the post-harvest phase, mainly for its little note epidemiology. The study presented some results about the possibility of preserving kiwifruit from skin pitting symptoms using alternative methods to fungicides. By in vitro assays, antagonist mechanisms of action against pathogen isolates were tested. Trichoderma harzianum (Th1) showed the highest inhibitory activity against C. luteo-olivacea isolates by volatile, non-volatile, and by dual culture assay, displaying an inhibition respectively by 90%, 70.6%, and 78.8%, and with respect to Aureobasidium pullulans (L1 and L8) by 23.3% and 25.8%, 50% and 34.7%, and 22.5% and 23.6%, respectively. Further, the sensitivity on CFU and mycelial growth of C. luteo-olivacea isolates to fludioxonil, and CaCl2 was tested, displaying interesting EC50 values (0.36 and 0.92 g L−1, 22.5 g L−1, respectively). The effect of Brassica nigra defatted meal was tested as biofumigation assays and through FT-IR (Fourier-Transform Infrared) spectroscopy. The above-mentioned treatments were applied in vivo to evaluate their efficacy on kiwifruits. Our data demonstrated that alternative solutions could be considered to control postharvest pathogens such as C. luteo-olivacea.


2007 ◽  
Vol 1 (2) ◽  
pp. 50-58 ◽  
Author(s):  
Amel Kerkeni ◽  
Mejda Daami-Rema ◽  
Neji Tarchoun ◽  
Mohamed Ben Khedher

2020 ◽  
Vol 55 (1) ◽  
pp. 27-34
Author(s):  
G. Zadehdabagh ◽  
K. Karimi ◽  
M. Rezabaigi ◽  
F. Ajamgard

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.


2020 ◽  
Vol 14 (4) ◽  
pp. 295-311
Author(s):  
Ada Gabriel ◽  
Mamman Mohammed ◽  
Mohammed G. Magaji ◽  
Yusuf P. Ofemile ◽  
Ameh P. Matthew ◽  
...  

Background: Snakebite envenomation is a global priority ranked top among other neglected tropical diseases. There is a folkloric claim that Uvaria chamae is beneficial for the management of snakebite and wounds in African ethnobotanical surveys. Besides, there are many registered patents asserting the health benefits of U. chamae. Objective: This study aimed to investigate U. chamae’s potentials and identify candidates for the development of tools for the treatment and management of N. nigricollis envenomation. Methods: Freshly collected U. chamae leaves were air-dried, powdered, and extracted in methanol. The median lethal dose of the extract was determined and further fractionated with n-hexane, n-butanol and ethyl acetate. Each fraction was tested for neutralizing effect against venom-induced haemolytic, fibrinolytic, hemorrhagic, and cytotoxic activities. Results: U. chamae fractions significantly (p<0.05) neutralized the haemolytic activity of N. nigricollis venom in n-butanol; 31.40%, n-hexane; 33%, aqueous residue; 39.60% and ethyl acetate; 40.70% at the concentration of 100mg/ml of each fraction against 10mg/ml of the snake venom when compared to the positive control. The fibrinolytic activity of N. nigricollis venom was significantly (p<0.05) neutralized in n-hexane at 73.88%, n-butanol; 72.22% and aqueous residue; 72.22% by the fractions of U. chamae. In addition, haemorrhagic activity of N. nigricollis venom was significantly (p<0.05) neutralized by U. chamae fractions at the concentrations of 100mg/ml, 200mg/ml and 400mg/ml except for n-butanol and aqueous residues at 400 mg/ml. Conclusion: U. chamae leaves fractions possess a high level of protection against N. nigricollis venoms-induced lethality and thus validate the pharmacological rationale for its usage in the management of N. nigricollis envenomation.


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