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General Info
| Code | Path XXI | |
|---|---|---|
| Title | Diversity of rhizome - root rot pathogens and their antagonists in cardamom | |
| Crop(s) | Cardamom | |
| Start year | 2010 | Closed |
| End year | 2015 | |
| Investigators | Name | Man-months |
| R Praveena | 15 | |
| C N Biju | 15 | |
Objectives
- To collect, identify and characterize rhizome - root rot pathogens infecting cardamom by employing morphological and molecular tools.
- To study the diversity of rhizome - root rot pathogens and their antagonists.
- To evaluate potential biocontrol agents against rhizome - root rot pathogens
Salient Achievements
- Surveys were carried out in Wayanad and Idukki districts of Kerala, Valparai in Tamil Nadu and Hassan and Kodagu districts of Karnataka. Incidence and severity of rhizome rot disease was higher in Meppadi panchayat of Kerala and Appangala and Kadagudalu areas of Karnataka.
- Eighty five fungal isolates were isolated from the samples of rhizome and root rot disease, of which R. solani, P. vexans and Fusarium species were found to be dominant.
- R. solani, P. vexans and Fusarium spp were found to be associated with rhizome rot disease of cardamom. Of the different species of Fusarium, F. oxysporum was found to be the predominant species. Identified the primary causal pathogen of rhizome/root rot diseases by sequential inoculation studies.
- 45 isolates of Trichoderma sp were isolated from the soil samples collected from Karnataka, Kerala and Tamil Nadu.
- 45 isolates of Trichoderma, Fusarium and Rhizoctonia isolates have been characterized based on morphological characters. Different species of Fusarium isolated were identified as F. oxysporum, F. solani, F. pallidoroseum and F. verticillioides. Rhizoctonia isolates from all the locations surveyed were identified as R. solani.
- Protocols for DNA isolation of F. oxysporum and Trichoderma have been standardized. The shortlisted efficacious Trichoderma isolates KA-1, KA-3, KA-20 (Karnataka), KL-3, KL-10, KL-13, KL-17, KL-19 (Kerala) and TN-3 (Tamil Nadu) were characterized based on ITS r-DNA sequencing.
- Under in vitro conditions, nine isolates of Trichoderma namely, KA-1, KA-3, KA-20 (Karnataka), KL-3, KL-10, KL-13, KL-17, KL-19 (Kerala) and TN-3 (Tamil Nadu) were effective against P. vexans (21.48 – 67.77%),R. solani (44.44 – 60.74%) and F. oxysporum (49.62 – 77.40%).
- Among the seven fungicides tested, P. vexans - carboxin + thiram (0.2%) and captan + hexaconazole (0.2%), R. solani- carboxin + thiram (0.2%) and tebuconazole (0.05%) F. oxysporum - tebuconazole (0.05%) were effective under in vitro conditions.
- Among the shortlisted nine efficacious Trichoderma isolates, the isolates KA-3 and KA-20 were effectiveagainst P. vexans and F.oxysporum and R. solani respectively under green house conditions.
- Among the three fungicides tested, tebuconazole (0.05%) was effective against R. solani and F. oxysporum, under glass house conditions, whereas the tested fungicides were not effective against P. vexans. The average per disease incidence in R. solani and F.oxysporum inoculated pots treated with tebuconazole was 11.59 &10.50 per cent respectively.
