Present status of groundnut bacterial wilt research in Indonesia.
Progress in research from the 1984/85 wet season to the 1991 dry season is reviewed. The disease is widely distributed in Indonesia, and is particularly important in West Java, Lampung, parts of Central and East Java, and South and North Sulawesi. Incidence in the field ranged from 15 to 35% on wilt-resistant cultivars and from 60-90% on susceptible ones. Two distinct symptoms were observed: typical wilting and a yellowing of the foliage followed by retarded growth. Isolates of Pseudomonas solanacearum varied in virulence and biochemical characteristics; those from different localities varied widely in virulence on the wilt-susceptible cv. Chico. All 250 isolates from groundnut tested were of biovar 3, except for one that was biovar 4. The isolates have a wide host range, including both weeds and economically important crops. The bacterium infected groundnut seeds and could be seed-transmitted. A number of local and introduced groundnut genotypes were resistant. Cultural methods such as rotation of groundnut with nonhost crops reduced disease intensity in the field; growing groundnut after flooded rice was the most effective cropping pattern to control bacterial wilt.