1IRRI, PO Box 933 Manila 1099, The Philippines; 2Department of Agriculture, Paholyothin Road, Chatuchak, Bangkok 10900, Thailand; 3Cuu Long Rice Research Institute, Omon, Can Tho, Vietnam

Unique features of the rice system that influence science and technology sharing
Rice is a unique crop to Asia as it is here that the species was first domesticated, where >90% of the global production is, and where most of the rice is consumed. Rice in Asia also grows in diverse production and ecological systems, ranging from no input, dryland rice, to intensive, high input wet (paddy) rice. Thus, no single technology is equally applicable to all the diverse rice systems. Disease management is also dictated by the large number of farmers, most of whom are illiterate and have small farms (3-5 ha average) with even smaller fields. Furthermore, because rice is so much a part of the culture in Asia, any potential risk or benefit from new technologies assumes special importance in the public sector. All these features present unique and difficult challenges when introducing new concepts, techniques and technologies to rice farmers. Furthermore, yield gaps between actual and attainable rice yields in irrigated and rainfed environments of Asia are estimated to range from 30-70%, at the time when there is urgency to produce even more rice, as much as 60-70% more than current levels in 30 years.

Contemporary technology for disease management
While the general groups of disease management techniques - host plant resistance, cultural, fungicides, biological, mechanical and physical - have not changed much since the beginning of the modern rice-growing era, the quality and use of these techniques has. The contemporary view is that these techniques must be used with supporting knowledge, formulated into knowledge intensive technologies (KITs) which allow farmers or others to make informed decisions about use of an input for rice production (such as seed, fertilizer, water or fungicide) or about a situation. Examples are a) diagnostic kits to detect disease before symptoms are visible and therefore ensure needed applications of fungicides, and b) decision-support tools or expert systems to guide farmers in their management strategies. The use of improved seed is a major accomplishment of modern farming; yet this has been criticized due to the unpredictable durability of resistance genes unless the seed is used with concomitant knowledge of its environment and how that affects the rate at which pathogen populations may evolve to overcome the resistance. Biological control is another technology that has reached application stage in rice. Based on the large-scale testing for against sheath blight control in Jiangsu Province, China, a production system has been developed that would respond directly and in a timely manner to farmers' needs, and could be used as a model for other developing countries.

Modes of communication
KITs require farmers to make timely decisions after assessing their farming environment; it is therefore important that large numbers of farmers learn the rules required to make such decisions. Different modalities have been evaluated for their effectiveness and efficiency to communicate KITs to large numbers of farmers - farmer participatory research, farmer field schools, and multimedia extension campaigns. It is as yet unclear which of these are most suited to a particular set of farmers characterized by the set's attributes like age, education and farming skills. What is further unclear is the role of information technology (computers, networks, etc.) to convey information to assist provincial decision makers in large rice growing countries such as India and China. Because these countries have big networks of human resources for pest management, the potential for information technology may be high if rice agriculture changes towards systems of less labor and larger farms. There are rich areas for multidisciplinary research.