Studies on the Bio-pesticidal Properties of Some Selected Flora for Eco-friendly Control of Fungal Diseases of Brinjal Field

Abstract

The present study was carried out to determine the effect of some medicinal plants and bio-agents on plant diseases like foot rot, root rot and fusarial wilt of brinjal (Solanum melongena). Twenty six medicinal plants and two bio-agents were applied for the control of diseases and antifungal effect was tested against Sclerotium rolfsii and Fusarium oxysporum that cause foot /collar rot, root rot and fusarial wilt diseases in Solanum melongena. These medicinal plants are Datura (Datura stramonium), Alamanda (Allamanda cathartica), Babla (Acacia nilotica) Hazarmony (Phyllanthus niruri), Telachcha (Coccinia cordifolia), Vat (Clerodendrum viscosum), Akando (Calotropis procera), Ata (Annona squamosal), Lantana (Lantana camara), Mahagony-Seed (Swietenia macrophylla), Jute-Seed (Corchorus caspsularis), Khoksha (Ficus hispida), Tobacco (Nicotiana tabacum), Chirota (Swertia chirata), Nishinda (Vitex negundo), Soj (Carum roxburghianum), Polygonum (Polygonum orientale), Mehedi (Lawsonia inermis), Tulsi (Ocimun sanctum), Ganda (Tagetes patula), Holde hurhurae (Cleome viscosa), Bell (Aegle marmelos), Arhar (Cajanus cajan), Neem (Azadirachta indica), Apang (Achyranthes aspera) and Garlic(Allium sativum). Extract of Acacia nilotica (babla) was found efficient in inhibiting the sclerotial and conidial germination of S. rolfsii and F. oxysporum correspondingly. The whole mycelial growth of S. rolfsii & F. oxysporum was inhibited by Acacia nilotica. The antifungal effect of crude medicinal plant extracts of 26 plants species was determined by in vitro study using water and methanol as a solvent following Poisoned Food Technique. The leaf extract of Nicotiana tabacum, L. camara, S. macrophylla and Corchorus capsularis completely inhibited the mycelial growth of S. rolfsii at 15% concentration. The in vitro study revealed that aqueous extract was more effective than methanol extract. Aqueous extracts of 13 plants datura (Datura stramonium), lantana (Lantana camara), babla ( Acacia nilotica), tulsi (Ocimum sanctum), akondo (Calotropis procera), garlic (Allium sativum), jute seed (Corchorus caspsularis), mahogany seed (Swietenia macrophylla), tobacco (Nicotiana tabacum), telachucha (Coccinia cordifolia), alamonda (Allamanda cathartica), hazarmony (Phyllanthus niruri) and khoksha (Ficus hispida) were tested in sterile soil and PDA media against the sclerotial germination. Extracts of Acacia nilotica, Datura stramonium, Swietenia macrophylla were found to inhibit in vitro germination of sclerotia of Sclerotium rolfsii compare to control. At 20% concentration Acacia nilotica, extract showed a high inhibition against sclerotial germination in both PDA and sterilized soil. Out of the 26 plant extracts in water, higher inhibition was noticed in 5 plants extracts namely Acacia nilotica, Allium sativum, Swietenia macrophylla, Datura stramonium and A. indica. Whereas, in methanol solvent, at 15% concentration complete inhibition was noticed in 3 plants extracts namely Acacia nilotica, Nicotiana tabacum and Swietenia macrophylla. Acacia nilotica at all concentration alone recorded 100% inhibition that showed maximum inhibition in water and methanol. Combination of Acacia nilotica with Corchorus capsularis and Nicotiana tabacum with Corchorus capsularis revealed excellent inhibition compare to control at 20% concentration against Fusarium oxysporum. The extract of A. sativum at highest concentration proved highly effective in reducing the spore germination of Fusarium oxysporum followed by extract of A. nilotica and Lawsonia inermis, respectively in ethanol extract, and the low efficiency was recorded in Lantana camara in all solvents. The inhibition in spore germination increases with corresponding increase in the extract concentration. Six isolates of Trichoderma spp. namely TRU-5, TRU-14, TB-23, TR-37, TD-44 and TTG-50 showed significant difference in mycelial growth among them after 24 hours, 48 hours and 72 hours. The Trichoderma isolate, TB-23 caused the maximum growth on PDA. Antagonistic activity of Trichoderma harzianum was conducted on PDA following dual culture plate technique against S. rolfsii and F. oxysporum. Aqueous extract of ten plants, one antagonist and two fungicides were tested on the vegetative growth and disease control of brinjal plant (Solanum melongena L.). Acacia nilotica, Allium sativum, Datura stramonium extracts and Trichoderma formulation were found most effective agent in controlling foot rot and wilt in comparison to control under field conditions. The formulated T. harzianum and Rhizobium bio-fungicide was tested against soil-borne pathogens of brinjal like Sclerotium rolfsii and Fusarium oxysporum causing foot and root rot and wilt diseases. All the substrates formulated with Trichoderma had significant effect in seed germination and decreasing seedling mortality as well as increasing plant growth over control. The result suggests that the application of plant extracts are growth promotive and effective in control of fungal diseases of brinjal field.