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

Abstract

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

Genetic resistance of local upland rice populations from East and North Kalimantan, Indonesia against some important diseases

“…It is a major constraint limiting the optimal production of crops included rice. Many studies have reported yield loss due to rice diseases in different intensity, from light to very severe yield losses (Sparks et al, 2012;Barnwal et al, 2013;Kihoro et al, 2013). As an example, the estimated annual loss of rice only due to blast disease was enough to feed 60 million people for one year (Pennisi, 2010).…”

Effects of extracts of Oxalis barrelieri L. and Cymbopogon citratus stapf, coupled with NaCl sorting on; seed health, germination and seedlings vigor of rice (Oryzae sativa L).

“…Bipolaris oryzae and Fusarium moniliforme, responsible for the brown spot disease and the bakanae disease in rice, respectively, are mainly found in rice seeds (Mew and Gonzales, 2002). Losses due to these pathogens range from 4 to 52% for B. oryzae (Barnwal et al, 2013) and 4 to 20% for F. moniliforme (Reddy and Sathyanarayana, 2001). Seed dressing of rice to overcome these pathogens has many advantages, including the protection of seed and seedlings against pathogens in the early stages of germination and development.…”

A Review on Products from Barley

“…The disease is of great importance in several countries and has been reported to cause enormous loss in grain yield (upto90%) particularly when leaf spotting phase assumes epiphytotic proportions as observed in Great Bengal Famine during 1942(Ghoseet al, 1960. The disease especially occurs in environment where water supply is scarce combined with nutritional imbalance particularly lack of nitrogen (Baranwal et al, 2013).…”