RECENT PROBLEMS AND STUDIES ON DOWNY MILDEW OF MAIZE IN INDONESIA

Abstract

In 1967 the area of maize (Zea mays L.) was approximately 3.3 million hectares (11) in Indonesia while the intensification program on maize in 1975 was approximately 370,000 hectares (1). Downy mildew (DM) of maize in Indonesia was first recorded by Raciborski in 1897. The disease in most prevalent below 900 m altitude (9) and is reported to occur most frequently on heavy soils (5 , 9). An overdose of nitrogen increase while potassium decrease susceptibility (2). Late planted, early rainy season maize was found to be more severely damaged by DM. Maize planted after maize or sugarcane was found to be the most highly diseased (3, 6, 9). There are slight differences in susceptibility among varieties (10) and the distribution of DM has increased since 1973 (13). The DM of maize in Java and Madura is incited by Sclerospora maydis (Rac.) Butler. The DM fungus of Minahasa (North Celebes) is Sclerospora philippinensis Weston (4) while the fungi other islands including the new area of distribution in Lampang Province, South Sumatra have not yet been determined. This paper summarizes the recent information on studies of the maize DM diseases in Indonesia. Some of the data and results were previously reported in 1972 (7).