Effect of Planting Techniques and Organic Amendments on the Management of Fusarium Wilt of Common Bean

Author: Tabasia Amin, Sheikh Saima Khushboo and Dechan Choskit

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Abstract

Fusarium wilt is the most serious disease of common bean causing 10 to15 per cent yield losses each year. It is a soil-borne fungal disease where water conducting (xylem) vessels become blocked. Based on morpho-cultural characters fungal pathogen isolated from infected roots of bean plant was identified as Fusarium oxysporum f.sp. phaseoli (Kendrick and Synder). Microscopic examination revealed mycelium as septate producing micro-macro conidia. The isolated fungus was put to pathogenicity test. The pathogenicity of the isolated fungus was proving by Koch’s postulates. Organic amendments like vermicompost @ 12.5 q ha-1+ seed priming with Trichoderma harzianum (109 cfu ml-1), FYM @ 20 t ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1), Vermicompost @ 12.5 q ha-1 and FYM @ 20t ha-1 along with planting techniques viz., ridges, raised bed and flat bed was tested against Fusarium oxysporum to manage the disease in field conditions. Vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109cfu ml-1) along with raised bed combination was used. The most effective treatment combination i.e. vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) exhibiting minimum disease incidence (16.42 %) was obtained when compared to control having 49.63 per cent disease incidence.

Keywords

Fusarium wilt, common bean, incidence, Trichoderma harzianum, organic amendment, planting technique

Conclusion

Under natural conditions, the disease symptoms first appeared on lower leaves in first week of August as yellowing of lower leaves followed by drying of the leaves, drooping of petioles and when stem was split open, reddish brown discolouration of the xylem vessels was noticed. Fungus isolated from infected roots of wilted common bean plants was tested for pathogenicity test by root dip inoculation techniques. The pathogenicity of the isolated fungus was established by proving Koch’s postulates. The culture of the pathogen produced characteristic disease symptoms after 16-20 days of inoculation. Therefore, pathogen was reisolated on potato dextrose agar medium and incubated at 25±1oC. The pathogen was found pathogenic on common bean and was identified as Fusarium oxysporum f.sp. phaseoli. The fungus produced colonies that were observed to be circular having white colour, cottony with profuse, fluffy aerial mycelium which gradually turned light pinkish, grayish white or creamish white. The mycelium is septate and hyaline with hyphal width 1.5-2 µm. The microconidia ranged from 2.5-(3.2)-3.5 × 7.0-(9.5)-13.0 µm. Macroconidia varied between 3.0-(3.5)-4.0 × 28-(33.5)-40 µm. Microconidia were aseptate. Macroconidia were septate with 4-5 septa. Chlamydospores were produced 12-15 days after incubation in cultures. They were globose, single celled, aseptae, produced terminally or intercalary with 8.210.5 × 6.60-9.90 μm size. On the basis of morphological characteristics of conidia, the pathogen was identified as Fusarium oxysporum f.sp. phaseoli. The culture was sent to the ITCC at IARI in New Delhi, and the identity of the isolate was confirmed as Fusarium oxysporum f.sp. phaseoli (Kendrick and Synder) under accession No. 12, 770;18. Studies on the effect of planting techniques and organic amendments on the management of Fusarium wilt of common bean revealed that vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum was found to be most effective treatment exhibiting minimum disease incidence of l6.42 per cent followed by FYM @ 20 t ha-1 + seed priming with Trichoderma harzianum showed incidence of 22.21 per cent as compared to negative control plot having 49.63 per cent incidence. This was followed by vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum and FYM @ 20 t ha-1 + seed priming with Trichoderma harzianum sown in ridges exhibiting 20.40 per cent and 24.01 per cent disease incidence respectively. Minimum per cent disease incidence was recorded in Trichoderma harzianum + vermicompost, which was at par with Trichoderma harzianum + FYM and was significantly superior over rest of the treatments including negative control. Among the treatments used, vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1). Among the interaction vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) along with raised beds exhibited highest per cent disease control over negative control. This was followed by vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) along with ridges. The highest numbers of pods per plant was recorded in the treatment vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on raised bed (20.41) and vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on ridges (19.66) compared with other treatments. The highest numbers of seeds per pod was recorded in the treatment vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on raised bed (7.16) and vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on ridges (6.91) compared with other treatments. The highest seed yield was recorded in the treatment vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on raised bed (13.1 q ha-1) and vermicompost @ 12.5 q ha-1 + seed priming with Trichoderma harzianum (109 cfu ml-1) when seeds were sown on ridges (12.4 q ha-1) compared with other treatments.

References

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How to cite this article

Tabasia Amin, Sheikh Saima Khushboo and Dechan Choskit (2021). Effect of Planting Techniques and Organic Amendments on the Management of Fusarium Wilt of Common Bean. Biological Forum – An International Journal, 13(4): 1311-1322.