Eco-friendly management of fungal leaf spot diseases of strawberry (Fragaria × ananassa Duch.) in Meghalaya /
S. V. , Nandeesha
Eco-friendly management of fungal leaf spot diseases of strawberry (Fragaria × ananassa Duch.) in Meghalaya / Nandeesha S. V. - Umiam : CPGSAS, CAU(Imphal), December 2024. - 274p. - [Plant Pathology, School of Crop Protection] .
Includes bibliographical references.
Strawberry (Fragaria × ananassa Duch.) is a highly valued fruit known for its delightful flavour, vibrant colour and rich nutritional profile, including high levels of vitamin C and antioxidants. It is infected by several diseases. Among them, fungal leaf spot pathogens pose significant threats by attackingthe foliage, reducing photosynthesis and serving as a source of inoculum for flower and fruit infections. These leaf spot diseases ultimately reduce the vegetative growth and yield. The effective eco-friendly management strategies are crucial to mitigate these losses and sustain the crop yield. This study aimed to isolate and characterize the native phylloplane microflora to combat these fungal leaf spot diseases of strawberry. In an extensive survey conducted for the fungal leaf spot diseases in major strawberry growing districts viz., Ri-Bhoi, East Khasi Hills and West Jaintia Hills of Meghalaya during 2021-22. It was noticed that the per cent disease incidence and per cent disease index ranged from 20.61 to 43.39 % and 9.67 to 25.33 % sustained for the Pestalotiopsis leaf spot (PLS), whereas 7.38 to 35.10 % and 3.33 to 18.33 % for Alternaria leaf spot (ALS) respectively. A total of 22 isolates of Pestalotiopsis sp. and 10 isolates of Alternaria sp. were isolated and their cultural, morphological and microscopic characters were studied and confirmed through the pathogenicity test by proving the Koch’s postulates. The most virulent isolates were subjected to molecular characterization and identified as Neopestalotiopsis clavispora (3 isolates), Alternaria alternata (1 isolate) and Alternaria tenuissima (2 isolates). A total of 86 bacteria and 52 fungi of native phylloplane microflora were isolated from healthy strawberry leaves by following three methods. Leaf impression method recovered the maximum microbial populations followed by modified leaf washing method and serial dilution plate method. Bacteria were found predominant in strawberry phylloplane compared to fungi. All the bacterial and fungal isolates were tentatively identified and grouped based on morphological and biochemical tests.The predominant bacteria tentatively identified were whitish and dry colony bacteria (22 isolates) followed by branching like growth colony bacteria (21 isolates), cream colony bacteria (20 isolates), whitish and viscid colony bacteria (12 isolates), yellow pigmented colony bacteria (7 isolates) and pink pigmented colony bacteria (4 isolates). The predominant fungi found were Aspergillus sp. followed by Trichoderma sp., Penicillium sp., Chaetomium sp., Fusarium sp., Monascus sp., Phoma sp., Cladosporium sp., Lasiodiploidia sp. and Epicoccum sp. All these bacterial and fungal isolates were screened against Neopestalotiopsis clavispora and Alternaria alternata by dual culture assay under in vitro condition. Based on dual culture assay, three prominent bacterial isolates (Um-B20 of 91.33 %, Sm-B18 of 89.93 % and UN-B11 of 81.48 %) and three prominent fungal isolates (P-F29 of 90.96 %, K-F24 of 87.22 % and U-F10 of 79.44 %) were selected. They were subjected to molecular characterization and identified as Pseudomonas fluorescens, Bacillus subtilis, Bacillus velezensis, Trichoderma asperellum, Trichoderma asperelloides and Aspergillus niger. Among the essential oils tested by poisoned food technique, T7 -Clove oil showed the best per cent inhibition (100 %) @ 500, 1000 and 1500 ppm which was followed by T5-Citronella oil (100 %) @ 1000 and 1500 ppm under in vitro condition. The potential one bacterial isolate (Pseudomonas fluorescens), fungal isolate (Trichoderma asperellum) and the essential oil (Clove oil @ 500 ppm) were used against Neopestalotiopsis clavispora under pot and field experiments. In pot experiment, T9 (Soil Application + Seedling Root Dip + Foliar Spray of Pseudomonas fluorescens @ 108 cells/ml) showed the lowest per cent disease index (1.48 %) and the highest disease reduction (98.31 %) after 3rd foliar spray, with the highest number of fruits (21.67/plant), yield (15.30 t/ha) and runners (12/plant) compared to other treatments. In field experiments, T9 (Soil Application + Seedling Root Dip + Foliar Spray of Pseudomonas fluorescens @ 108 cells/ml) showed the lowest per cent disease index (2.34 %) after 3rd foliar spray, with the highest number of fruits (30.22/plant), yield (24.65 t/ha), benefit cost ratio (2.99) and runners (13.68/plant). Thus, the present study revealed that the native phylloplane bio-agent (Pseudomonas fluorescens @ 108 cells/ml) in the form of soil application, seedling root dip and foliar spray can be used successfully to manage the fungal leaf spot diseases of strawberry in Meghalaya.
Strawberry--Diaseases--Ecofriendly management.
Fungal leaf spots.
Eco-friendly management of fungal leaf spot diseases of strawberry (Fragaria × ananassa Duch.) in Meghalaya / Nandeesha S. V. - Umiam : CPGSAS, CAU(Imphal), December 2024. - 274p. - [Plant Pathology, School of Crop Protection] .
Includes bibliographical references.
Strawberry (Fragaria × ananassa Duch.) is a highly valued fruit known for its delightful flavour, vibrant colour and rich nutritional profile, including high levels of vitamin C and antioxidants. It is infected by several diseases. Among them, fungal leaf spot pathogens pose significant threats by attackingthe foliage, reducing photosynthesis and serving as a source of inoculum for flower and fruit infections. These leaf spot diseases ultimately reduce the vegetative growth and yield. The effective eco-friendly management strategies are crucial to mitigate these losses and sustain the crop yield. This study aimed to isolate and characterize the native phylloplane microflora to combat these fungal leaf spot diseases of strawberry. In an extensive survey conducted for the fungal leaf spot diseases in major strawberry growing districts viz., Ri-Bhoi, East Khasi Hills and West Jaintia Hills of Meghalaya during 2021-22. It was noticed that the per cent disease incidence and per cent disease index ranged from 20.61 to 43.39 % and 9.67 to 25.33 % sustained for the Pestalotiopsis leaf spot (PLS), whereas 7.38 to 35.10 % and 3.33 to 18.33 % for Alternaria leaf spot (ALS) respectively. A total of 22 isolates of Pestalotiopsis sp. and 10 isolates of Alternaria sp. were isolated and their cultural, morphological and microscopic characters were studied and confirmed through the pathogenicity test by proving the Koch’s postulates. The most virulent isolates were subjected to molecular characterization and identified as Neopestalotiopsis clavispora (3 isolates), Alternaria alternata (1 isolate) and Alternaria tenuissima (2 isolates). A total of 86 bacteria and 52 fungi of native phylloplane microflora were isolated from healthy strawberry leaves by following three methods. Leaf impression method recovered the maximum microbial populations followed by modified leaf washing method and serial dilution plate method. Bacteria were found predominant in strawberry phylloplane compared to fungi. All the bacterial and fungal isolates were tentatively identified and grouped based on morphological and biochemical tests.The predominant bacteria tentatively identified were whitish and dry colony bacteria (22 isolates) followed by branching like growth colony bacteria (21 isolates), cream colony bacteria (20 isolates), whitish and viscid colony bacteria (12 isolates), yellow pigmented colony bacteria (7 isolates) and pink pigmented colony bacteria (4 isolates). The predominant fungi found were Aspergillus sp. followed by Trichoderma sp., Penicillium sp., Chaetomium sp., Fusarium sp., Monascus sp., Phoma sp., Cladosporium sp., Lasiodiploidia sp. and Epicoccum sp. All these bacterial and fungal isolates were screened against Neopestalotiopsis clavispora and Alternaria alternata by dual culture assay under in vitro condition. Based on dual culture assay, three prominent bacterial isolates (Um-B20 of 91.33 %, Sm-B18 of 89.93 % and UN-B11 of 81.48 %) and three prominent fungal isolates (P-F29 of 90.96 %, K-F24 of 87.22 % and U-F10 of 79.44 %) were selected. They were subjected to molecular characterization and identified as Pseudomonas fluorescens, Bacillus subtilis, Bacillus velezensis, Trichoderma asperellum, Trichoderma asperelloides and Aspergillus niger. Among the essential oils tested by poisoned food technique, T7 -Clove oil showed the best per cent inhibition (100 %) @ 500, 1000 and 1500 ppm which was followed by T5-Citronella oil (100 %) @ 1000 and 1500 ppm under in vitro condition. The potential one bacterial isolate (Pseudomonas fluorescens), fungal isolate (Trichoderma asperellum) and the essential oil (Clove oil @ 500 ppm) were used against Neopestalotiopsis clavispora under pot and field experiments. In pot experiment, T9 (Soil Application + Seedling Root Dip + Foliar Spray of Pseudomonas fluorescens @ 108 cells/ml) showed the lowest per cent disease index (1.48 %) and the highest disease reduction (98.31 %) after 3rd foliar spray, with the highest number of fruits (21.67/plant), yield (15.30 t/ha) and runners (12/plant) compared to other treatments. In field experiments, T9 (Soil Application + Seedling Root Dip + Foliar Spray of Pseudomonas fluorescens @ 108 cells/ml) showed the lowest per cent disease index (2.34 %) after 3rd foliar spray, with the highest number of fruits (30.22/plant), yield (24.65 t/ha), benefit cost ratio (2.99) and runners (13.68/plant). Thus, the present study revealed that the native phylloplane bio-agent (Pseudomonas fluorescens @ 108 cells/ml) in the form of soil application, seedling root dip and foliar spray can be used successfully to manage the fungal leaf spot diseases of strawberry in Meghalaya.
Strawberry--Diaseases--Ecofriendly management.
Fungal leaf spots.