Search

Sclerotium rolfsii (Sacc.) is the causal agent of stem-rot in groundnut (Arachis hypogaea L.)crop. With the increase in demand for the groundnut, control of stem-rot efficiently by microbial strains is fast becoming inevitable as the conventional system of chemicals is degrading our ecosystem. This investigation here emphasizes on inoculation of arbuscular mycorrhizal fungi (AMF) and Trichoderma species for growth achievement and disease control. The present investigation showed that these microbial strains were found to be worth applying as they stimulated growth and decreased harmful effects of S. rolfsii (cv. ‘Western-51’). The increased biochemical parameters and antioxidant activities also indicated their defence related activities in groundnut plants. In spite of positive attributes meted out by these microbial strains towards groundnut crop, the interaction among AM fungi and Trichoderma species seemed to be less co-operative between each other which were noted when mycorrhizal dependency and percent root colonization were observed. However, in summary more practical application of low-input AM fungi along with Trichoderma species may be needed for the advancement of modern agricultural systems.

The present experiment was conducted at University of Pune for biocontrol of soil-borne plant pathogen Sclerotium rolfsii by incorporating arbuscular mycorrhizal fungi (Glomus fasciculatum) and conventional system of cultivation with different spacing pattern (15 and 30 cm) in field. Both mycorrhizal inoculation and 30 cm spacing pattern significantly increased growth and yield as compared to control or 15 cm spacing pattern. The pathogenic mycorrhizal groundnut plants in 30 as well as 15 cm spacing pattern showed better growth in terms of plant height, leaf and pod number, fresh and dry weight of whole groundnut plant in comparison to non-mycorrhizal pathogenic ones and the plant growth was better in 30 spacing than 15 cm. The colonization by AM fungi in both spacing pattern was higher in absence of pathogen S. rolfsii. However, pathogen’s presence decreased the mycorrhizal colonization considerably in 30 and 15 cm. The disease severity and incidence were recorded to be lowered when inoculated with mycorrhiza in pathogenic groundnut plants as compared to non-mycorrhizal pathogenic ones in both spacing pattern and incidence and severity was significantly lower in 30 cm as compared to 15 cm. Therefore, it was observed from our results that for management of soil-borne pathogens inoculation of AM fungi and spacing patterns are necessary.

The fungal pathogen causes serious widespread losses to agricultural crops worldwide. Therefore, economy of countries may worsen especially of developing countries. In addition, harmful chemical pesticides which are being used today for increasing crop production creates very serious health hazardous problems to human beings and ecosystem as a whole. The antagonistic potential of Trichoderma species which has been long known to control various soil-borne fungal pathogens in biological way may be utilized. The faster growth rates with which it competes with fungal pathogen mainly brings upon their antagonistic characteristics. An investigation was carried out in laboratory condition towards biological efficacy of T. viride on potato dextrose agar (PDA) medium for the bio-control of soil-borne plant pathogens Sclerotium rolfsii and Macrophomina phaseolina in in-vitro condition. The dual culture technique was followed in which T. viride showed significant antifungal activities towards both the pathogens. T. viride significantly inhibited the mycelial radial growth of S. rolfsii by 75% and M. phaseolina by 71.42%. The results showed variable mycelial growth rate for all fungal isolates which was determined after 6 days of incubation in which T. viride showed minimum of 4.00 days to completely cover the petri-plates and S. rolfsii showed 4.33 days whereas M. phaseolina showed 6.33 days. Thus, T. viride showed encouraging results regarding their biopesticidal and biofungicidal potential against plant pathogens which may be endorsed to substitute harmful chemical supplements that exists in modern day agricultural practices.

A pot experiment was conducted on peanut Arachis hypogaea L. during 2007 growing season to determine their growth characteristics due to mycorrhizal inoculation and two different levels of soluble phosphorous application. Due to inoculation by AM fungi the growth parameters such as leaf number, shoot length, root length, fresh weight, dry weight, pod number and nodule number were significantly increased but two different level of phosphate also showed growth. However, growth parameters showed variable results when two different level of phosphate was applied along with AM fungi. Without phosphorous the mycorrhizal groundnut showed significant growth but when first low level of phosphorous was applied it showed more significant growth, however most significant result was observed with second high level of phosphorous application to the groundnut plant. Total chlorophyll content and acid and alkaline phosphatase activity was also significantly higher but most significant were observed when first level of phosphorous was applied followed by second level of phosphorous. The percent root colonization by mycorrhizal fungus Glomus fasciculatum was higher due to application of phosphorous but mycorrhizal dependency went on decreasing due to increase in the level of phosphorous. The different level of phosphorous had significant effect on growth and physiological parameters of mycorrhizal and non-mycorrhizal Arachis plants after 30, 60 and 90 days of growth period. However, the obtained results proved the improvement in plant growth with application of phosphorous. Thus, for increase in production of groundnut in the state of Maharashtra seems to be feasible option for increasing the overall production and yield.