Isolation and identification of some pathogenic fungi associated with cassava (Manihot esculenta Crantz) root rot disease in Cameroon

Attempts were made to evaluate the potential biological factor causing poor growth (stunting) of alfalfa (Medicago sativa L.) on some soils in Central Alberta. Paratylenchus projectus which associates with stunted alfalfa was extracted from an affected soil. Alfalfa seedlings grown in sterilized sand culture assemblies were inoculated with P. projectus alone and in combination with dilutions from sterilized and non-sterilized affected and normal soils. Other studies included the effects of various sterilized and non-sterilized soil dilutions from an affected soil on plant growth and incidence of alfalfa stunting symptoms. Results indicate that P. projectus is not the biological factor causing alfalfa stunting. Typical stunting symptoms were observed on plants receiving non-sterilized soil dilutions from an affected soil, and the consistency of development of irregular reddish-brown root lesions on stunted plant roots confirmed the presence of other biological factor(s) causing the disease. It was reasonably well established that the root rot disease was caused by a microorganism(s). Further studies regarding root lesioning, isolation and identification of the microorganisms are being carried on in this laboratory.

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Efficiency of Trichoderma spp. against of some pathogenic fungi causing of broad bean root rot disease

Journal of Physics Conference Series ◽

10.1088/1742-6596/1294/9/092003 ◽

2019 ◽

Vol 1294 ◽

pp. 092003

Author(s):

Ahed Abd Ali Hadi Matloob

Keyword(s):

Root Rot ◽

Broad Bean ◽

Pathogenic Fungi ◽

Trichoderma Spp ◽

Root Rot Disease ◽

Bean Root ◽

Rot Disease

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The influence of rhizosphere soil fungal diversity and complex community structure on wheat root rot disease

PeerJ ◽

10.7717/peerj.12601 ◽

2021 ◽

Vol 9 ◽

pp. e12601

Author(s):

Xuejiang Zhang ◽

Heyun Wang ◽

Yawei Que ◽

Dazhao Yu ◽

Hua Wang

Keyword(s):

Root Rot ◽

Fungal Diversity ◽

Rhizosphere Soil ◽

Pathogenic Fungi ◽

Wheat Root ◽

Ammonium Nitrogen ◽

Wheat Roots ◽

Root Rot Disease ◽

Filling Stage ◽

Rot Disease

Wheat root rot disease due to soil-borne fungal pathogens leads to tremendous yield losses worth billions of dollars worldwide every year. It is very important to study the relationship between rhizosphere soil fungal diversity and wheat roots to understand the occurrence and development of wheat root rot disease. A significant difference in fungal diversity was observed in the rhizosphere soil of healthy and diseased wheat roots in the heading stage, but the trend was the opposite in the filling stage. The abundance of most genera with high richness decreased significantly from the heading to the filling stage in the diseased groups; the richness of approximately one-third of all genera remained unchanged, and only a few low-richness genera, such as Fusarium and Ceratobasidium, had a very significant increase from the heading to the filling stage. In the healthy groups, the abundance of most genera increased significantly from the heading to filling stage; the abundance of some genera did not change markedly, or the abundance of very few genera increased significantly. Physical and chemical soil indicators showed that low soil pH and density, increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Our results revealed that in the early stages of disease, highly diverse rhizosphere soil fungi and a complex community structure can easily cause wheat root rot disease. The existence of pathogenic fungi is a necessary condition for wheat root rot disease, but the richness of pathogenic fungi is not necessarily important. The increases in ammonium nitrogen, nitrate nitrogen and total nitrogen contributed to the occurrence of wheat root rot disease. Low soil pH and soil density are beneficial to the occurrence of wheat root rot disease.

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A Study of the Effect of Bioagent Trichoderma harzianum Rifai, the Fungicide Topsin-M and their Interaction on Root Rot Disease of Okra Abelmoschus esculentus in the Field

Basrah Journal of Agricultural Sciences ◽

10.37077/25200860.2019.280 ◽

2019 ◽

Vol 32 ◽

pp. 320-336

Author(s):

Yehya A. Salih ◽

Noor M. Mansoor

Keyword(s):

Trichoderma Harzianum ◽

Root Rot ◽

Pathogenic Fungus ◽

Pathogenic Fungi ◽

Dry Weight ◽

Macrophomina Phaseolina ◽

Root Rot Disease ◽

Fruit Productivity ◽

Rot Disease ◽

Fungus Growth

This study aimed to investigate the effect of interaction between Trichoderma harzianum and the fungicide Topsin-M on root rot disease that infected okra in the field. Three fungi were isolated from the root of okra that infected with root rot disease: Fusarium solani, Rhizoctonia solani and Macrophomina phaseolina. The pathogenicity of these fungi was tested and found to be they cause root rot disease on okra, the disease severity was 41.7, 6.7 and 31.7% respectively. The laboratorial experiments showed that T. harzianum had a high antagonism ability with degrees of 1 and 2 against the pathogenic fungi M. phaseolina, F. solani and R. solani respectively. Also, it was found that the fungicide Topsin –M inhibited the growth of all pathogenic fungi with a percent of 100%, while it inhibited the bioagent fungus growth with a percent of 50.4 %, therefore it be recommended for the interaction experiments. The field results showed that using of bioagent T. harzianum and fungicide topsin-M significantly reduced the infection percentage and severity disease of the pathogenic fungi F. solani, R. solani and M. phaseolina to 65.3, 21.20, 13.20, 46.20, 25.70 and 18.20% respectively, compared to each pathogenic fungus alone which were 71.00, 60.20, 60.20, 66.80, 80.20 and 60.20% respectively. The interaction between the bioagent T. harzianum and topsin-M led to increase the plant height, fresh and dry weight of shoot and root systems and the fruit productivity of the examined okra plants .

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Biocontrol Agents for Controlling Wheat Root Rot Disease under Greenhouse Conditions

Indian Journal of Agricultural Research ◽

10.18805/ijare.a-528 ◽

2020 ◽

Author(s):

M.M. Abdel-Kader ◽

N.S. El-Mougy ◽

M.S.A. Khalil ◽

N.G. El-Gamal

Keyword(s):

Root Rot ◽

Pathogenic Fungi ◽

Wheat Root ◽

Infested Soil ◽

Wheat Seedlings ◽

Fungal Isolation ◽

Root Rot Disease ◽

Wheat Diseases ◽

Rot Disease ◽

Soil Borne Fungi

Background: The most important wheat diseases that caused by soil-borne fungi are the root-rot disease. The current investigation conducted with evaluation the efficacy of some bioagents, Bacillus subtilis, Pseudomonas fluorescens, Azospirillum brasilense, Trichoderma harzianum, commercial bioagent (Planta guard) and chitosan against the causal pathogenic organisms of wheat root rot disease under greenhouse conditions. Methods: Wheat seedlings infected with root rot disease were subjected to the causal fungal isolation trails. In greenhouse, wheat grains were sown individually in pots containing artificially infested soil with the pathogenic fungi R. solani or F. graminearum. Furthermore, the tested bioagents and the fungicide Topsin-M 70 were applied to the infested soil before sowing. Result: The isolated fungi were R. solani or F. graminearum had proved their pathogenic ability to induce root rot disease of wheat. In pot experiment, all applied treatments affect root rot incidence of grown wheat seedlings in artificially infested soils with disease incidents. In infested soils with root rot incidents, bacterial bioagents reduced root rot incidence by 84.5-93.6% and 28.4- 35.3% 66.6, respectively and by 43.7% for T. harzianum. Moderate effect was obtained by chitosan and planta guard treatments in soil infested with either pathogenic fungi.

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Local Trichoderma strains as a control strategy of complex black root rot disease of strawberry in Egypt

Bulletin of the National Research Centre ◽

10.1186/s42269-019-0206-7 ◽

2019 ◽

Vol 43 (1) ◽

Author(s):

Farid Abd-El-Kareem ◽

Ibrahim E. Elshahawy ◽

Mahfouz M. M. Abd-Elgawad

Keyword(s):

Root Rot ◽

Disease Incidence ◽

Pathogenic Fungi ◽

Dry Weight ◽

Biological Pest Control ◽

Potato Dextrose Broth ◽

Black Root Rot ◽

Root Rot Disease ◽

Growth Area ◽

Rot Disease

Abstract Background Economics and human safety to avoid health risks caused by fungicides are materializing new era of biological pest control. Trichoderma species ranked high among other agents to control complex black root rot disease of strawberry caused by Fusarium solani, Rhizoctonia solani, and Pythium sp. Our study aimed to document the efficacy of local strains representing T. harzianum, T. viride, T. virinis, and T. koningii against such a disease. Materials/methods These strains were cultured separately on potato dextrose broth medium to test their inhibitory effect against strawberry black root rot in vitro and in vivo. Strawberry growth and yield were also assessed relative to the untreated check and the fungicide Actamyl. Activity of peroxidase and chitinase were measured in plant leaves using spectrophotometer. Results Each of the antagonistic fungal strains significantly reduced growth area of all pathogenic fungi collectively causing the disease. Trichoderma harzianum, T. viride, and T. koningii reduced the growth area more than 90.6% for all tested pathogenic fungi. Each species significantly reduced disease incidence and severity under field conditions. The highest reduction in the disease incidence and severity, 83.3 and 88.5% respectively, was attained by mixture of the four species. This mixture increased the strawberry fresh and dry weight by 83.3 and 176.9%, respectively, and the yield by 117.1%. All Trichoderma species tested significantly increased the activity of two plant defense-related enzymes of strawberry plants against the pathogens. Their mixture attained the highest increase of peroxidase and chitinase activity by 150 and 160.9%, respectively. Conclusions While the fungal mixture could considerably increase the strawberry fresh and dry weight as well as the yield, it suppressed the incidence and severity of the disease. So, integrated pest management in ways that make these biocontrol agents complementary or superior to chemical fungicides should further be examined against this disease.

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