The Incidence and Severity of Major Diseases on Siamese Malangke Citrus (Citrus nobilis) in West Malangke District, North Luwu Regency, South Sulawesi
T Kuswinanti1*, B Patandjengi1, M Faried2 and S Laban3

1Department of Plant Protection, Faculty of Agriculture, Universtas Hasanuddin, Makassar, 90245
2Department of Agronomy, Universtas Hasanuddin, Makassar, 90245
3Study Program of Soil Science Faculty of Agriculture, Universtas Hasanuddin, Makassar, 90245

Abstract

North Luwu Regency was once the center of Siamese citrus in Indonesia with an area of 21,615 ha. The production and productivity in 1999 respectively 86,732 tones or equivalent of 21.89 t/ha. However, the presence of Citrus Vein Phloem Degeneration (CVPD) and root- and stem rot diseases, the productivity was decreased significantly, and finally in 2005 the Siamese citrus plantations in North Luwu was destroyed. Various technological innovations that were applied to restore the success of siem malangke citrus plantation i.e. indexing of main diseases in the citrus plantation, determining pilot gardens, production and application of biopesticides, biodecomposers and designing tree architecture. The observation showed that the intensity of CVPD was quite high in the two villages surveyed, namely 55.24% in Pengkajoang Village and 58.70% in Waelawi Village. Validation of the causal agent of CVPD was carried out by molecular analysis using specific primers OI and OI2c resulted an amplicon in size of 1160 bp. The analysis was carried out in the laboratory Molecular Biology of the Research and Development Center in Malang, East Java. Typical symptoms of CVPD disease are the leaves become yellow, bones of leaves dark green, the leaves become more rigid and thicker than the healthy leaves and small. While the fruits becomes small and hard. Basal stem rot was only found in the citrus plantation of Waelawi village, with an incidence of up to 90%, while the severity varies between 45% and 58%. The plants infected with Botryodiplodia theobromae became dry, accompanied by the release of gummosis in the form of a golden yellow liquid on the stems, branches or twigs of citrus plants. While root- and stem rot diseases caused by Phytophthora sp. were only found in Waelawi village with a low incidence ranging from 11.45% to 21.62%, but the intensity reached 60.15%. Phytophthora causes a slow decline of the tree, especially in new plantings. The leaves turn light green or yellow and may

Keywords: Citrus, CVPD, Phytophthora citrophthora, Botryodiplodia theobromae

Topic: Integrated Pest and Disease Management