Emerging trends in the management of bud rot disease of coconut
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Date
2004-12
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Abstract
In recent times there has been a resurgence of bud rot incidence more or less everywhere in the coconut-growing zones. Though application of Bordeaux mixture is very effective, there are practical difficulties in its implementation. Thesc reasons necessitate the formulation of an alternative IDM strategy for bud rot management. For bud rot management to be effective, a sound forecasting model(s) is an essential one. Considering this, attempts were made to develop forecasting models, based on macro and micro temperature, relative humidity (in plains and hilly areas), and rate of survival of the inoculum in endemic areas during off-season. As an alternative to Bordeaux mixture, systemic fungicides were evaluated: Aureofungin - sol (36.4 g I palm)followed by Calixin (21 ml I palm) as stem injection was found effective. The protection offered against bud rot pathogenby these systemic chemicals extended up to 8 weeks, thus safeguarding the palms during vulnerable period. No residues could be detected in nut water and kernal up to six months after application in the case of Calixin. Hence, the systemics can be administered in advance, well before the onset of the monsoon and there is no need-to climb the tree since the chemical can be administered from the ground. An endophytic bacterium (Bacillus amyloliqriefaciens), a fungus (Trichodernia harzianurn) and botanicals (Andrographispaniculata and Lawsonia inerntis) were found very effective against F palmivora. As these botanicals are not compatible with the antagonist, Z harzianurn sequential application of botanicals and Z har:ianlim by maintaining a suitable interval between the applications is suggested. With the use of standardized ex viva varietal screening technique, a tall cultivar, Laccadive Ordinary (LO) and a dwarf cultivar. Ganga Bondam (GB) were identified as bud rot tolerant varieties. Formulating an IDM strategy combining all the above practices, viz., planting resistant / tolerant varieties, bud rot forecasting based on weather parameters. application of systemic fungicides as prophylactic and application of antagonists (bacterium and fungus) and botanicals for long term sustenance of disease suppression is discussed in this paper.
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Keywords
Bud rot, Phytophthora palmivora, integrated disease management (IDM), disease forecasting, systemic fungicides, antagonistic organisms, biological control
Citation
Journal of Plantation Crops 32(Suppl.) December 2004: 269-279