In vitro assessment of extracts of Azadirachta indica and Chromolaena odorata against Lasiodiplodia pseudotheobromae Asman Asman (a,b*), A H Nufus (a), A B Cahyani (a), A Rosmana(a,b), N Amin (a), A Fakhruddin (c), N U Natsir (c)
(a) Department of Plant Pests and Diseases, Hasanuddin University, South Sulawesi, Indonesia
(b) Cocoa Research Group (CRG), Faculty of Agriculture, Hasanuddin University, South Sulawesi, Indonesia
(c) Agricultural Quarantine Major Service of Makassar.
*asman[at]agri.unhas.ac.id
Abstract
Cocoa dieback disease is one of the significant cocoa diseases caused by the fungus Lasiodiplodia species including L. pseudotheobromae. Applying botanical fungicides is one of the potential alternative controls for this disease due to the disease being considered an emerging disease in cocoa in Sulawesi. The major objective of this study was to assess neem (Azadirachta indica) and siam weed (Chromolaena odorata) leaf extract to inhibit the colony growth of L. pseudotheobromae. The experiment used three different concentrations: 1%, 3%, and 5%. The in vitro evaluation was carried out through the poison food technique using potato dextrose medium both in solid medium and liquid medium. The result showed that A. indica and C. odorata performed well in the suppression of the L. pseudotheobromae colony growth in three different concentrations in a solid medium. C. odorata 5% significantly inhibited the colony growth of L. pseudotheobromae (50%), followed by C. odorata 1% (18%), C. odorata 3% (17%), and A. indica 5% (10%), A. indica 3% (7%), A. indica 1% (3%). A. indica and C. odorata significantly reduced the mycelium biomass of L. pseudotheobromae until 88% inhibition on wet biomass. The highest inhibitor for the wet biomass parameter is C. odorata 5% (88%), followed by A. indica 5% (86%), and C. odorata 1% (85%). C. odorata 5% (94%) is the higher inhibitor for dry biomass parameter, followed by C. odorata 3% (83%) and 1% (75%), A. indica 5% (70%), 3% (48%), and 1% (33%). A. indica and C. odorata could be used as alternative control for L. pseudotheobromae.
Keywords: neem extract, cocoa dieback disease, alternative control
