First Report of Phytophthora sansomeana (E.M. Hansen) Causing Leaf Blight of taro (Colocasia esculenta (L.) Schott) in South Eastern Nigeria

Ugwuja, F.N.; Chiejina, Nneka Virginia; Ugwuoke, K. I.; Akanwa, F. E.; Onifade, A. K.; Tatfeng, Mirabeau Youtchou

doi:10.9734/ijpr/2022/v9i230221

Cited by 6 publications

(4 citation statements)

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“…On maize P. sansomeana causes wilting and stunting and may be related to emergence problems [38], though interestingly, reports from this host lag behind that of soybean in the U.S. and globally. P. sansomeana was also recently isolated from leaf lesions in taro [42]. Artificial inoculation yielded the same lesions as seen on field hosts on detached leaves.…”

Section: On Non-soybean Hostsmentioning

confidence: 60%

Phytophthora sansomeana, an Emerging Threat to Soybean Production

Detranaltes

Cai

2022

Agronomy

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In 1990, new Phytophthora strains, later recognized as a new species, Phytophthora sansomeana, were found to cause Phytophthora root rot (PRR) in soybean in addition to P. sojae. The emergence and spread of a second pathogen causing PRR poses a significant threat to soybean production. While genetic resistance to P. sojae has been developed and widely deployed as a management tool, these varieties appear largely ineffective at controlling P. sansomeana, which has a broad host-range and can infect and survive on non-leguminous hosts including fir trees, Rosaceous fruit trees, maize, and several herbaceous weeds. This contributes potential for broad distributions worldwide across both agricultural and natural ecosystems. Despite having been studied since the 1980s under a variety of informal designations, little is known about the epidemiology, host-interactions, and management of this emergent pathogen. Due to the lack of management options, increased frequency of first reports in new geographic areas, and the overall limited body of knowledge surrounding this novel pathogen, P. sansomeana warrants more research attention from both biological and disease management perspectives. The aim of this review is to summarize the hosts, distribution, pathogenicity, and current management strategies of P. sansomeana and to provide a concise record of where it has been studied under other informal designations. Its role in PRR of soybean is emphasized due to the economic magnitude of PRR-associated losses and its well-documented aggressiveness as a soybean pathogen.

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Section: On Non-soybean Hostsmentioning

confidence: 60%

Phytophthora sansomeana, an Emerging Threat to Soybean Production

Detranaltes

Cai

2022

Agronomy

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“…Tremendous losses attributed to this pathogen were earlier reported in Pacific Islands (American Samoa, Western Samoa, Hawaii, Fiji and Papua New Guinea), India and China, Mauritus, Indonesia, Philippines and many other countries 1,5,25,29,30 . Significant reductions in the nutritional and phytochemical constituents of infected corms have also been reported 31 .…”

Section: Introductionmentioning

confidence: 99%

In vitro Control of Phytophthora colocasiae Causing Leaf Blight of Taro (Colocasia esculenta (L.) Schott.) With Selected Botanical Extracts

Ugwuja,

Ehumadu,

Omodamiro

et al. 2024

Asian J. Plant Pathol.

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Background and Objective: Leaf blight incited by Phytophthora colocasiae has been a major challenge impacting on yield and commercialization of taro (Colocasia esculenta (L.) Schott) in Nigeria since 2009. This study evaluated in vitro, the efficacy of selected plant extracts against the causal pathogen. Materials and Methods: Four botanical extracts: Azadirachta indica A. Juss. Eucalyptus camaldulensis Dehn, Senna alata L. and Tithonia diversifolia (Hemsley) A. Gray were tested in vitro for their fungi toxic effects on radial growth and mycelia dry weight of the pathogen at 5, 10 and 20 mg/mL of each extract. Ridomil (0.67 mg/mL) and zero treatment were set along tests and treatments were replicated thrice in a Completely Randomized Design. Data were subjected to analysis of variance at a 95% confidence interval using the SPSS package and significant differences among means were compared using Duncan's Multiple Range Test (DMRT). Results: All the extracts exhibited significantly varying degrees of inhibition in the radial growth and mycelia dry weight tests. Percentage inhibition increased as the concentration increased. Azadirachta indica and S. alata extracts at 20 mg/mL inhibit 100 and 97.13% radial growth, respectively and were significantly (p<0.05) superior to 40.00 and 31.81% caused by T. diversifolia and E. camaldulensis, respectively. Complete (100%) inhibition of mycelia dry weight was obtained with S. alata and T. diversifolia extracts at all the selected concentrations while A. indica and E. camaldulensis showed high inhibition at some concentrations. Conclusion: These extracts have strong inhibitory effects against P. colocasiae and are comparable to the synthetic fungicide Ridomil, therefore, their exploration in the management of TLB is strongly advocated.

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“…"Phytophthora colocasiae Raciborski is of prime importance because it can reduce corm yield by up to 50% and leaf yield by 95% in susceptible varieties. Corm rots usually develop after harvest and entire corms can decay in 7-10 days and causes heavy loss during storage" [6].…”

Section: Introductionmentioning

confidence: 99%

Report on Phytophthora sp. Causing Corm Rot of Colocasia (Colocasia esculenta L.) from Prayagraj, Uttar Pradesh, India

Nirmala,

A. Lal,

Simon

2024

J. Sci. Res. Rep.

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Taro [(Colocasia esculenta L.) Schott] also known as old cocoyam or true cocoyam is a water-loving herbaceous plant. Taro is affected by major diseases and pests in different parts of the world but among them taro blight and corm rot caused by a fungus-like oomycete Phytophthora colocasiae Racib is most important disease. The infected corm samples were collected from markets in two districts of Andhra Pradesh and the experiment was carried out based on Koch’s postulates in the Department of Plant Pathology, SHUATS, Prayagraj during Rabi season (2022-23). Isolation was done from collected corm samples (infected corms) for identification of the pathogen. Based on the cultural and morphological characters under microscopic examination, the pathogen was identified as Phytophthora sp. which causes corm rot and leaf blight of Colocasia. The isolated pathogen was inoculated into the healthy corms of Colocasia. At the time of corm germination, the typical symptoms were observed like downy whitish growth on the surface of the corms and on the leaf surface as small grey to brown discoloured water-soaked spots which later enlarged, became dark brown and coalesced, ﬁnally destroyed entire leaf lamina. After the examination of the symptoms, reisolation was done and pathogenecity of the fungus was proved by Koch’s postulates. Perusal of the literature revealed that Phytophthora sp. causes post and pre harvest corm rot and leaf blight in colocasia and it seems to be the first report from Prayagraj, Uttar Pradesh.

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First Report of Phytophthora sansomeana (E.M. Hansen) Causing Leaf Blight of taro (Colocasia esculenta (L.) Schott) in South Eastern Nigeria

Cited by 6 publications

References 0 publications

Phytophthora sansomeana, an Emerging Threat to Soybean Production

Phytophthora sansomeana, an Emerging Threat to Soybean Production

In vitro Control of Phytophthora colocasiae Causing Leaf Blight of Taro (Colocasia esculenta (L.) Schott.) With Selected Botanical Extracts

Report on Phytophthora sp. Causing Corm Rot of Colocasia (Colocasia esculenta L.) from Prayagraj, Uttar Pradesh, India

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