Crop losses caused by rice brown spot disease in mangrove swamps of northwestern Sierra Leone

Fomba, S. N.; Singh, Naveen

doi:10.1080/09670879009371518

Cited by 13 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, earlytransplanted rice crops appear particularly susceptible to both leaf scald and leaf smut, especially under Nfertilization. The economic importance of leaf scald and leaf smut diseases is yet to be defined under mangrove swamp conditions in Sierra Leone, as has been done for brown spot (Fomba, 1987;Fomba and Singh, 1990). 56-8 (53-5-60-1) Field water-dry season, April (sterile) 37-6 (36-0-39-2) Field water-wet season, July (sterile) 53-8 (53-0-54-8) River water-dry season, April (sterile) 37-8 (36-2-39-4) River water-wet season, July (sterile) 53-8 (52-5-55-0) t Based on the mean of 10 microscopic fields and/or transects per treatment replicated twice (confidence limits, P= 0-05); percentage conidial germination arcsin transformed.…”

Section: Discussionmentioning

confidence: 99%

“…Associated mangrove swamps are freshwater grass/sedge swamps which are seasonally flooded in the wet season but are essentially dry during most of the dry season and are adjacent to tidal mangrove swamps. Brown spot has been further confirmed as a key disease in the mangrove environment of Sierra Leone (Fomba, 1987;Fomba and Singh, 1990). The present study was therefore conducted between 1983 and 1985 cropping seasons to define the effect of time of planting, nitrogen application, field conditions of salinity and acidity and some weather parameters on the incidence of C. miyabeanus in a mangrove swamp ecosystem at Rokupr Experimental Farm in northwestern Sierra Leone.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Observations on the incidence of rice brown spot, leaf scald and leaf smut diseases in a tidal mangrove swamp at Rokupr, Northwestern Sierra Leone

Fomba

Singh

1991

Tropical Pest Management

Self Cite

View full text Add to dashboard Cite

The ecological behaviour of Cochliobolus miyabeanus (Ito et Kurib.) Drechsl. ex Dast. (Bipolaris oryzae (Breda de Haan) Shoem.), causal agent of brown spot of rice (Oryza sativa L.), was investigated in a tidal mangrove swamp at Rokupr Experimental Farm, northwestern Sierra Leone. Disease increased where transplanting was delayed. This was probably due to the coincidence of flowering with favourable environmental conditions for disease development from November to February. Nitrogen fertilization at 40kg N ha -1 significantly (P = 0.05) reduced C. miyabeanus incidence in 1983, but not in 1984 and 1985 cropping seasons at the same site. Grain yields of ROK 5, a medium-duration improved rice cultivar (ca. 150 days) were significantly reduced in late-transplanted rice crops (September to November) in spite of adequate N fertilization. Mangrove mud was not an important source of C. miyabeanus propagules. Incidence of leaf scald caused by Monographella albescens (Thum) Parkinson, Sivanesan and Booth (Microdochium oryzae (Hashioka and Yokogi) Samuels and Hallet) and leaf smut caused by Entyloma oryzae Miyake were generally stimulated by N application.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Observations on the incidence of rice brown spot, leaf scald and leaf smut diseases in a tidal mangrove swamp at Rokupr, Northwestern Sierra Leone

Fomba

Singh

1991

Tropical Pest Management

Self Cite

View full text Add to dashboard Cite

show abstract

“…The range of reported yield losses to BS, often expressed in relative terms, is variable from 4 to 29 % (Bedi and Gill 1960), about 12 %, (Aluko 1975), from 8 to 23 % (Fomba and Singh 1990) from 26 to 52 % (Chakrabarti 2001). The latter figures represent a broader and higher range because it accounts for losses caused by grain infection.…”

Section: Importance Of Brown Spotmentioning

confidence: 99%

A review on crop losses, epidemiology and disease management of rice brown spot to identify research priorities and knowledge gaps

Barnwal

Kotasthane²,

Magculia

et al. 2013

Eur J Plant Pathol

View full text Add to dashboard Cite

Rice brown spot (BS) is a chronic disease that affects millions of hectares of rice every growing season, grown by some of the most resource-poor farmers. Despite its widespread occurrence and impact, much still needs to be understood about BS. Reported yield losses in relative terms vary widely from 4 to 52 %. However, accurate, systematic estimates are lacking. BS is conventionally perceived as a secondary problem that reflects rice crops that experience physiological stresses, e.g. drought and poor soil fertility, rather than a true infectious disease. Much remains to be understood about the mechanisms leading to epidemics and crop losses. Quantitative and qualitative knowledge gaps exist in our understanding of the epidemiological processes, sources of resistance and biocontrol methods. In this review we identify several of these gaps, which if filled, could lead to a strong impact on the management of brown spot. We also use the architecture of a simulation model to position and prioritize these knowledge gaps, assess the epidemiological consequences of disease management options on

show abstract

“…In India, brown spot was recorded to reduce tiller number and also reduce the yield of 19.2-58.8% (Vidhyasekaran and Ramadoss 1973;Chattopadhyay et al 1975). In Africa, yield loss caused by brown leaf spot was reported about 12% in Nigeria (Aluko 1975), and from 8% to 23 % in North Sierra Leone (Fomba and Singh 1990). Meanwhile, reports on yield loss caused by brown spot in Indonesia are unavailable at present.…”

Section: Introductionmentioning

confidence: 99%

Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia

2020

View full text Add to dashboard Cite

Abstract. Mau YS, Ndiwa ASS, Oematan SS. 2020. Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia. Biodiversitas 21: 1625-1634. Brown spot is one of the most devastating diseases of rice, which could lead to total yield loss. The disease has a worldwide distribution, more specifically in areas where water supply is scarce, most specifically in the dry upland areas. Almost all stages of rice are affected by the disease, where leaves and grains are mostly affected. Considerable differences exist in susceptibility to brown spot among rice varieties, which may cause a large variation in yield loss caused by the disease. Therefore, the resistance level of rice varieties and their yield reduction has to be regularly evaluated and updated. There are only a few reports on the relationship between brown spot severity with yield and yield loss of upland rice, and is even lacking in pigmented upland rice. The objectives of the present study were to assess the brown spot severity and resistance level in pigmented upland rice cultivars from East Nusa Tenggara Province, Indonesia, and to elucidate their relationships with yield and yield reduction. Twenty four pigmented upland rice genotypes were evaluated in the field during May to October 2019, and their disease responses and yields were recorded. Disease severity was observed weekly and used to calculate Area Under the Disease Progress Curve (AUDPC) for comparison among the genotypes. The relationships between disease severity and AUDPC with yield and yield loss were also examined. The results showed significant variation in brown spot severity and AUDPC, ranging from, respectively, 11.11% to 40.70% and 398.42%-days to 1081.30%-days. Yields and yield losses of test genotypes also varied substantially. Yields under diseased-free and diseased plots ranged from, respectively, 2.34 t ha-1 to 6.13 t ha-1 and 1.68 t ha-1 to 3.74 t ha-1 while yield loss was between 10.46% and 56.15%. Six genotypes were moderately resistant, four genotypes were moderately susceptible and 14 genotypes were susceptible to brown spot. Neither disease severity nor AUDPC had a linear relationship with yield but both exhibited positive and linear relationships with yield loss.

show abstract

Crop losses caused by rice brown spot disease in mangrove swamps of northwestern Sierra Leone

Cited by 13 publications

References 6 publications

Observations on the incidence of rice brown spot, leaf scald and leaf smut diseases in a tidal mangrove swamp at Rokupr, Northwestern Sierra Leone

Observations on the incidence of rice brown spot, leaf scald and leaf smut diseases in a tidal mangrove swamp at Rokupr, Northwestern Sierra Leone

A review on crop losses, epidemiology and disease management of rice brown spot to identify research priorities and knowledge gaps

Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia

Contact Info

Product

Resources

About