back to Country Profiles

For further information on Potato Production click here

1. Late blight occurrence and LB severity by major production area in the country. What crops were affected (tomato, potato, others)? Disease sources (seed, cull piles, volunteer plants, soil)?

Potato in Indonesia is generally grown in upland areas, at altitudes higher than 1000 m.a.s.l. The total potato area is about 62000 ha; significant potato growing areas are found in North and West Sumatra, in West, central and East Java, and in North Sulawesi. Due to the very humid climate, Late blight is a major constraint to potato production. Contributing to the problem is the fact that potato is mainly grown during the rainy season: during the dry season insufficient water and/or irrigation facilities are available. Little is known about differences in severity between the different potato growing areas, but it can safely be assumed that the problem is serious in all provinces. Farmers mainly deal with the disease by applying high amounts of fungicides.

2. LB impact (foliar damage, yield losses, tuber rot occurrences)?

The average farm price of potato is 2000 Rupiah/kg, (about 0.22 US$ in 2004 rates), which makes it a profitable crop to grow. A conservative estimate is that about 224 US$/ha is spent on fungicides; nationwide this would add up to 11.2 million US$. Assuming an average yield reduction due to Late Blight of about 15% (a global figure), this would add 180 million US$ to the damage in Indonesia. Although these figures are substantial, the impact on food security is very limited, since the average Indonesian eats only 4 kg potatoes per year. The impact of Late Blight on the chipping industry is more significant since the main processing variety is Atlantic. This variety originates in North America and was clearly not bred with the humid tropics in mind: it is even more susceptible to Late Blight than Granola. Therefore, its cultivation is risky and difficult and farmers are not enthusiastic to grow it. Although the industry raised prices for processing potato, they are still often in short supply and have to import potatoes. Obviously, for the Indonesian economy, it would be better if potatoes could be bought on the domestic market.

3. Fungicide use (amounts, types, etc.)?

The most popular contact fungicides are mancozeb and maneb; the most popular systemic ones are Curzate (cymoxanil) and Acrobat (dimetomorph). Metalaxyl is not used too often (during the season of the survey, 17% of the farmers used it). Other fungicides that are commonly used are: Daconil (cholorothalonil), Antracol (propineb), and Copper oxychloride. A conservative estimate is that about 224 US$/ha is spent on fungicides.

4. Other LB control measures (resistant cultivars, forecast systems, none)?

Currently, resistant varieties are not grown at a significant scale: 90% of the potato area is planted with susceptible variety Granola; 6% are grown with processing varieties, mainly the very susceptible variety Atlantic, and some other varieties. Currently, a group of 45 clones from the International Potato Center with horizontal resistance against Late Blight (B3C1 population) are under evaluation in a joint project of CIP and BALITSA, the national institute for vegetable research. One previously introduced resistant CIP clone, LBr-40, is now close to varietal release; it is to be named ‘Repita’.

Forecasting

No known attempts have been made to employ Late Blight forecasting systems

Cultivation practices

Crop spacing is relatively wide, normally 80 x 30 cm, which probably contributes to creating a somewhat less conducive microclimate for the development of Late Blight. Foliage is generally cut about one week before harvest, which helps in the prevention of tuber blight.

Late blight resistant cultivars.

Resistant cultivars are not yet grown at a significant scale.

5. LB control effectiveness (fungicide or host resistance failures)?

Farmers generally are able to control Late Blight satisfactorily by using fungicides. Although they have limited knowledge on proper use of such agents, they achieve reasonable results by the sheer quantity and frequency of their applications. Since farmers often use different agents during one season and the share of metalaxyl is not too high, resistance problems are not seeming to much of a problem. However, the high amounts of fungicides that are applied pose a threat to the farm families and the environment, and the high cost of fungicides decreases the profitability of potato cultivation.

6. Pathogen strains (mating type, fungicide resistance, virulence factors, etc)?

The presence of mating type A2 was reported by Nishimura, Sato, et all, 1999. They also found isolates that were highly resistant to metalaxyl.

7. Disease risks and/or major needs?

There is an urgent need to reduce fungicide loads, both to protect farm families and to protect the environment. This could be achieved by improving farmers’ knowledge and improve spraying practices, in combination with the introduction of varieties with durable resistance, such as the B3C1 clones that are currently being evaluated.

8. Any publications on late blight in the country?

Nishimura R, Sato K. et al. 1999. Distribution of Phytophthora infestans populations in seven Asian countries. Annals of the Phytopathological Society of Japan 65: 163–170.

9. Is tuber blight an increasing problem?

No systematic research has been done on the incidence of tuber blight.

10. Additional comments

Prepared by Sander de Vries. 2004. Country report on late blight in Indonesia, Proceedings of the Regional Workshop on Potato Late Blight for East and Southeast Asia and the Pacific held 24–25 August 2004 in Yezin, Myamar.