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Overview of Blackgram and Foliar Diseases
- Blackgram (Vigna mungo L.)
- Important short-duration pulse crop grown extensively in Andhra Pradesh, India.
- Contributes significantly to global pulse production (28% of total production).
- Accounts for 65% of global acreage and 54% of production in India.
Importance of Managing Foliar Diseases
Biotic and Abiotic Stresses
- Low productivity due to various stresses, primarily diseases.
- Diseases cause an estimated yield loss of 20-30% (Singh, 1995).
Major Foliar Fungal Diseases
- Powdery Mildew (Erysiphe polygoni):
- Prevalent in cool, dry weather, causing significant yield losses (9-50%).
- Other diseases include rust and leaf spots, especially during late growth stages.
Need for Fungicides
- Absence of resistant cultivars necessitates the use of fungicides to manage diseases.
- Fungicides evaluated to manage foliar diseases effectively.
Experimentation
Study Design: Conducted in Rabi seasons of 2014, 2015, and 2016.
- Location: Agricultural Research Station, Utukur.
- Design: Randomized Block Design with six treatments and untreated control.
- Variety Used: LBG 752 with specified spacing for cultivation.
Administration of Fungicides:
- Sprays started after initial disease symptoms with follow-ups every 15 days.
- Disease Severity Assessment: Recorded using a 0-5 scale (Mayee and Datar, 1986).
- Scale from 0 (no infection) to 5 (high incidence).
Results
- Efficacy of Fungicides: All treatments outperformed control significantly.
- Carbendazim @ 0.1%:
- Most effective, lowest PDI of 34.15%, highest seed yield of 925 kg/ha.
- Cost-Benefit Ratio: 1:1.68.
- Other Treatments included Mancozeb, Chlorothalonil, Propineb, etc.
Detailed Results Summary
- Pooled Data of Efficacy (Rabi 2014, 2015 & 2016):
- Carbendazim: PDI 34.15%, Yield 925 kg/ha, C:B ratio 1:1.68.
- Average PDI and yield results across treatments.
- Untreated control had the highest PDI (58.39%).
Economic Analysis
- Cost of Cultivation and Returns:
| Treatment | Seed Yield (kg/ha) | Gross Returns | Cost of Cultivation | Net Returns | C:B Ratio | |
|---|---|---|---|---|---|---|
| Mancozeb @ 0.20% | 812 | 48,720 | 20,820 | 27,900 | 1:1.34 | |
| Chlorothalonil @ 0.15% | 767 | 46,020 | 21,100 | 24,920 | 1:1.18 | |
| Carbendazim @ 0.10% | 925 | 55,500 | 20,670 | 34,830 | 1:1.68 | |
| Propineb @ 0.15% | 908 | 54,480 | 20,805 | 33,675 | 1:1.61 | |
| Captan + Hexaconazole @ 0.10% | 873 | 52,380 | 20,738 | 31,642 | 1:1.52 | |
| Propiconazole @ 0.10% | 785 | 47,100 | 21,450 | 25,650 | 1:1.19 | |
| Untreated Control | 723 | 43,380 | 20,000 | 23,380 | 1:1.16 | |
| Note: Market price of Blackgram was Rs 60/kg. |
Conclusion
- Fungicide treatments significantly improved yield and reduced disease severity in blackgram.
- Carbendazim @ 0.1% shown to be the most effective option in terms of yield and economic returns.
References: Include studies and cited works that provide background on fungicide use and analysis of diseases related to blackgram.