Rice tungro virus, grassy stunt virus and ragged stunt virus have been a potential menace to rice production. Research on these virus diseases in the past ten years has resulted in an improvement of the understanding of their biology and ecology to enable the development of effective methods to control these diseases. An integrated control technique combining the use of resistant varieties, cultural practices and insect control has brought about a considerable decrease in virus infection in our rice crop in the last 3 vears.
A varietal rotation scheme has been successfully implemented for tungro virus in South Sulawesi. Varietal resistance is used extensively for grassy stunt virus, in combination with cultural practices and insecticidal spray. Yellow dwarf and orange leaf diseases are present but are less important.
Soybean, green gram, peanuts, cowpea are among the important legume crops in the country. New viruses identified in the last 10 years are soybean dwarf, soybean stunt, soybean mosaic, and bean yellow mosaic on soybean, black gram mosaic, bean yellow mosaic, mungbean mosaic on green gram; peanut mottle, on peanuts; cowpea aphid-borne mosaic, soybean yellow mosaic on cowpea. These viruses are considered to be the limiting factor in leguminous crop seed production.
Seed infection with some viruses plays an important role in the dissemination of the diseases and means of effective control of such a problem will be studied in the coming years.