S. K. Awasthi

Eco-friendly management of red rot disease of sugarcane with Trichoderma strains

Eighty strains of Trichoderma harzianum and T. viride occurring in sugarcane rhizosphere soil of sub-tropical zone were isolated on Trichoderma specific medium and tried screened in vitro against Colletotrichum falcatum. Highly potent ones (Th 37 & Th 38) were tried to manage red rot disease under field conditions. Healthy setts were treated by applying Trichoderma mixed culture (TMC) of T. harzianum strains grown in sterilized maize bran (2 kg) and subsequently mixed with sterilized press mud or FYM (20 kg) / ha. The treatment was also compared with spore suspension containing 106 conidia / ml and metabolites (2.5% culture filtrate). Combinations were also tried for improving efficiency. The trials were repeated thrice in CoLk 7701, a highly susceptible variety / genotype. Disease management was ascertained by inoculation challenged with potent Colletotrichum falcatum pathotype (Cf 09). Infection of C. falcatum was protected in 45–55% plants. There was no infection in such plants as against 97–100% infection in check. Red rot infection was also considerably suppressed in 20–25% plants. Where grade of infection was reduced to 2–4 in 0–9 scale. Testing was made at an appropriate temperature (300 C) and high relative humidity (90%) during July–August. The protection offered might be due to direct parasitic action of T. harzianum on C. falcatum and also systemic resistance induced in sugarcane. Application of T. harzianum is useful for management of red rot and cultivation of moderately resistant varieties for several years. It is also useful for reducing the economical losses in susceptible varieties. The yield was also enhanced by 15–20 t / ha due to improved germination and shoot biomass. Application of Trichoderma biopesticide is eco-friendly, economical and efficient for improving soil health also.

Trichoderma induced improvement in growth, yield and quality of sugarcane

Trichoderma harzianum andT. viride were significantly effective in improving germination (6-14%), tiller population (21-78%), millable canes (5-30%), yield (6-38%) and CCS t/ha (30-34%) over the control in plant cane of CoS 94257. Metabolites of both the species @ 2.5% were found to be more efficient and significantly better than spore suspension (106 conidia/ml) and TMC containingTrichoderma @ 2 kg/ha in 20 kg sterilized farm yard manure (FYM). The metabolites improved tiller count (53-78%), millable canes (27-30%) and yield (34-38%). The yield boost up by the metabolites was up to 81.9 t/ha withT. viride and 79.8 t/ha withT. harzianum over 59.3 t/ha of control. The differences in yield due to both the species were significant.T. viride alone was tested for improving the yield of ratoon. The emergence of clumps was enhanced with spore suspension, TMC and metabolites ofT.viride. The metabolites were, significantly superior for increasing the number of clumps (43.2%) than the other treatments (1.7-20.1%) and control.T. viride metabolites were also better for producing more tillers (75%) and millable canes (40%). The improvement in yield ranged from 53.16 t/ha to 76.31 t/ha with metabolites and 72.13 t/ha with double doze of TMC, half applied at clump emerging stage and half at tiller stage. CCS t/ha was also enhanced in ratoon crop by 40% with metabolites and 36% with double doze of TMC. Application ofT. harzianum andT.viride was found to be economical, non hazardous and useful for soil health. The benefit cost ratio suggests that by expending*Rs. 1000/ ha onTrichoderma in sugarcane a benefit of Rs. 11500/ in plant cane/ha and Rs. 16500/ in ratoon /ha may be obtained.

Biological control of sugarcane smut (Sporisorium scitamineum) through botanicals and Trichoderma viride

Culmicolus smut (Sporisorium scitamineum Meike), the sett borne pathogen causes considerable loss to sugarcane productivity especially to ratoon crop. Use of fungicides may cause environmental hazards besides residual problem. Therefore, twenty five plant species and Trichoderma viride was evaluated in vitro against smut pathogen (Sporisorium scitamineum). Out of twenty five plant species, leaf extracts (10%) of Calendula officinalis, Solanum nigrum and culture filtrate (5%) T. viride (bioagent) inhibited mycelial growth and teliospore germination of S. scitemineum. In plant crop, smut incidence was 2.07% in dipping of infected setts in leaf extract of S. nigrum before planting, while in remaining treatments it ranged between 3.38 to 7.28% as against 11.3% in control. In ratoon crop, the smut incidence was 5.38% in the same treatment, while in rest of the treatments it ranged between 6.85 to 9.94 per cent as against 15.3% in control. However, sett treatment with T. viride culture filtrate (5.0%) was superior among all the treatments as it improved germination (6.2%), millable canes (27.33%) and cane cane yield (38.18%) in plant crop and sprouting of clumps (12.57%), millable canes (51.46%) and yield (48.75%) in ratoon crop, respectively.

Integrated management strategies for red rot disease of sugarcane.

Field experiments were conducted during 2006–07 and 2007–08 crop seasons at IISR institute farm, Lucknow to find out the impact of Integrated Disease Management (IDM) practices over Non-Integrated Disease Management (NIDM) i.e. normal package of practices of cane cultivation on red rot incidence, yield and quality parameters of sugarcane in plant and ratoon crops of moderately susceptible variety CoSe 92423. It was observed that in both plant and ratoon, IDM practices reduced red rot incidence, enhanced growth parameters and quality attributes of sugarcane compared to NIDM practices. In plant crop of IDM practices, germination was improved by 6.29%, tiller counts (16.93%); millable canes (4.90%); yield (13.09%); juice extraction (2.33%); pol % juice (0.46%); purity (0.88%), CCS (16.47%), plant height (8.90%), cane girth (13.52%); internodes (12.67%); internodal length (3.00%) and cane weight (34.04%) over NIDM practices. In ratoon crop, improvement in clump emergence (30.0%), height of cane (14.76%), cane girth (7.66%), internodes (5.31%); internodal length (14.04%); cane weight (18.90%); juice extraction (5.56%); pol % juice (0.84%); purity (2.12%), CCS t/ha (22.42%), tiller counts (19.77%), millable canes (12.09%) and yield (18.38%) was observed in IDM over NIDM practices. Thus, this study revealed that use of T. viride is beneficial for controlling red rot, improving quality attributes, enhancing yield and shelf life of a moderately red rot susceptible variety.

Deep Tillage, Soil Moisture Regime, and Optimizing N Nutrition for Sustaining Soil Health and Sugarcane Yield in Subtropical India

ABSTRACT A field experiment was conducted at ICAR-Indian Institute of Sugarcane Research, Lucknow, with three tillage practices (T1: Control- two times ploughing with harrow and cultivator, each followed by planking before sugarcane planting; T2: Deep tillage with disc plough (depth 25–30 cm) before planting followed by harrowing, cultivator, and planking; and T3: Subsoiling at 45–50 cm and deep tillage with disc plough/moldboard plough (depth 25–30 cm) followed by harrowing, cultivator, and planking before planting, two soil moisture regimes (M1: 0.5 irrigation water (IW)/cumulative pan evaporation (CPE) ratio and M2: 0.75 IW/CPE ratio) at 7.5 cm depth of IW, and four N levels (N1- 0, N2- 75, N3- 150, and N4-225 kg N ha−1) in sugarcane plant crop. Deep tillage and subsoiling increased porosity and reduced bulk density in surface/subsurface soil. Further, these physical changes also improved soil biological and chemical properties responsible for higher crop growth and yield. Deep tillage and subsoiling reduced the compaction by 6.12% in 0–15 cm depth in sugarcane plant crop at maximum tillering stage. The highest N uptake (158.5 kg ha−1) was analyzed with deep tillage and subsoiling compared to all other tillage practices. Maintaining suboptimal moisture regime with deep tillage and subsoiling showed the highest IW use efficiency (157.16 kg cane kg−1 N applied). Mean soil microbial biomass carbon (SMBC) in ratoon crop was higher compared to plant crop. During initial tillering stage, ratoon crop showed higher SMBC with application of deep tillage and subsoiling (1209 mg CO2-C g−1 soil day−1) at 0–15 cm depth and 1082.9 mg CO2-C g−1 soil day−1 at 15–30 cm depth. Thus, it could be concluded that besides improving sugarcane yield, soil health could be sustained by adopting subsoiling (45–50 cm depth) and deep tillage (20–25 cm depth), with soil moisture regime of 0.75 IW/CPE and application of 150 kg N ha−1 in sugarcane (plant crop).