000			06248nam a22002177a 4500
999			_c291830 _d291830
082			_a634.9 _bKIR/CH Ph.D
100			_a Kiran Mohan
245			_aCharacterization,Documentation and Management of fungal diseases of selected forest nursery seedlings of Kerala
260			_aVellanikkara _bDepartment of Forest Resource Management,College of Forestry, Vellanikkara _c2024
300			_a172,LVIp.
502			_aPh.D
520	3		_aDisease free planting stock significantly ensures better field survival, thereby reducing the burden of economic loss and meeting the targets of climate change mitigation. Teak (Tectona grandis L.f.), Indian beech (Pongamia pinnata (L.) Pierree), custard apple (Annona squamosa L.), guava (Psidium guajava L.), and Indian laburnum (Cassia fistula L.), which are extensively used for afforestation programs in Kerala, are severely affected by fungal pathogens at the nursery stage. Hence, an investigation was undertaken to identify the major fungal diseases associated with the above mentioned seedlings in Kerala and to assess the efficacy of selected fungicides and bio-control agents through in vitro and in vivo studies. A purposive sampling survey was conducted in 40 forest nurseries across the state during summer (Feb-May), monsoon (June-Sept), and post-monsoon (Oct-Jan) seasons in 2021 to monitor the occurrence of fungal diseases and collect diseased samples. Out of the seven major fungal diseases, three from teak, and one each from the other four tree crops were observed respectively. Major fungal diseases noticed from teak seedlings include teak leaf rust (TLR), teak die back (TDB), and teak leaf spot (TLS). Pongamia foliar disease (PFD) from Indian beech, annona die back (ADB) from custard apple, guava leaf spot (GLS) from guava, and cassia die back (CDB) from Indian laburnum are the other selected major diseases. Teak leaf rust (TLR) was the most common and severe foliar disease observed in teak from various nurseries across the state and irrespective of the five agro-ecological zones (AEZs), the maximum Percent Disease Index (PDI) and Percent Disease Severity (PDS) (60.0% and 52.8%, respectively) recorded from Chettikkulam (AEZ IV- High Hills) in the monsoon season. Teak die back (TDB) disease (PDI 62%) was observed only from Edayazham (AEZ I- Coastal Plain) during the pre-monsoon period. Teak leaf spot (TLS) was noticed only from Kudayathoor nursery (AEZ III- Foothills) during the pre-monsoon season. In Indian beech, PFD was observed from different nurseries irrespective of AEZs during the study period, and Chettikkulam (AEZ IV- High Hills) recorded the maximum PDI (80.0%) and PDS (63.2%) in the monsoon. The major disease of custard apple seedlings, i.e., ADB, was observed from different nurseries, and the maximum PDI (55.0%) was recorded at Kanakappalam (AEZ III- Foothills). Guava leaf spot (GLS) was noticed as the common disease in guava seedlings during the survey, and the maximum PDI (60.0%) and PDS (55.0%) were recorded at Varanadu nursery (AEZ I- Coastal Plain). In Indian laburnum, CDB was found to be a common disease throughout the state, and at the location Kattamudy (AEZ IV- High Hills), it recorded the maximum PDI (50.0%). Based on the available data during the study period, TLR showed a positive correlation with temperature and a negative correlation with rainfall. However, PFD showed a negative correlation with temperature and a positive correlation with rainfall and ADB showed a positive correlation with rainfall as well as relative humidity. In the case of GLS, no common trend was detected, and CDB showed a negative correlation with relative humidity. The typical orange colour urediniospores on the backside of the affected teak leaf characterizes TLR symptoms. Meanwhile, TLS is noticed as scattered black spots with a greyish center. Whereas TDB originates as leaf blight and subsequently spreads throughout the seedlings. Symptoms of PFD are observed as irregular chlorotic spots on the adaxial side and black dot-like sporodochia on the abaxial side. Leaf yellowing, followed by inward curling and the further spread of a necrotic area throughout the seedling, is the typical symptom of ADB. Meanwhile, GLS is noticed as grey to cream-colored blighted region surrounded by black, brown, or violet round margin. In the case of CDB, the initial symptom of leaf blight later spreads throughout the seedling. The pathogenicity of the major foliar diseases (TLR, TLS, PFD, GLS) was proven using Mycelial Bit Inoculation Method (MBIM), Micro Droplet Inoculation Technique (MDIT), and inoculation with the infected leaf method. Spore suspension method and mass multiplied pathogen in the substrate method were adopted for major root diseases (TDB, ADB, CDB). The obligate parasite (TLR) was identified as Olivea tectonae based on the morphological characters of urediniospores and all other major pathogens were identified upto the species level based on cultural as well as morphological characters, coupled with characters of amplified gene regions (ITS region and LSU region). The TDB pathogen was thus identified as Colletotrichum fruticola, TLS pathogen as Corynespora cassiicola, PFD pathogen as Cladosporium tenuissimum, ADB pathogen as Colletotrichum siamense, GLS pathogen as Colletotrichum siamense, and CDB pathogen as Alternaria alternata. In vitro evaluation studies revealed that carbendazim 12% + mancozeb 63%, mancozeb, and propineb stood out against major foliar diseases. However, in vivo experiment results showed that carbendazim 12% + mancozeb 63%, mancozeb, hexaconazole, and Trichoderma asperellum were observed to be efficient against major foliar diseases. Similarly, carbendazim 12% + mancozeb 63%, mancozeb, Bordeaux mixture, and hexaconazole showed promising results against major root diseases during in vitro as well as in vivo experiments.
650			_aForest Resource Management
650			_aForestry
650			_aCharacterization Documentation and Management
650			_aFungal diseases
650			_aseed
700			_aGopakumar, S(Guide)
856			_uhttps://krishikosh.egranth.ac.in/handle/1/5810220544
942			_2ddc _cTH