PATHOLOGY TRIALS

Plant Pathology Trials

The following experiments were conducted in the discipline of Plant Pathology under the All India Coordinated Research Project (AICRP) on Cotton at different centers in North Zone (Faridkot, Bathinda, Hisar, ICAR-CICR RS Sirsa, Sriganganagar), in Central Zone (Akola, Nanded, Surat, Bharuch, Junagadh, Khandwa, Bhawanipatna, ICAR-CICR-Nagpur) and South Zone (Lam Guntur, Dharwad, TNAU Coimbatore):Path.1 Observations on the occurrence of the diseases (in farmer’s fields and research farms)

• Path.1(a) Observations on the occurrence of various diseases
• Path.1(b) Disease progress in relation to weather factors
• Path.1(c) Studies on the variability in Alternaria causing leaf spots in cotton
• Path.1(d) Survey and epidemiology of TSV
• Path.1(e) Studies on the variability in Corynespora leaf spot in cotton

Path. 2 Screening of AICRP entries for disease reaction and confirmation

• Path.2(a) Screening of breeding lines for disease reaction
• Path.2(b) Confirmation and maintenance of diseaseresistant lines
• Path.2(c) Monitoring of resistance against CLCuD in cotton

Path. 3 Management of cotton diseases

• Path.3(f) Management of sooty mold (Capnodium spp.) in cotton
• Path.3(h) Evaluation of efficacy of bioagents against cotton diseases
• Path.3(i) Integrated management of CLCuD through its vector management
• Path.3(j) Management of boll rot and foliar diseases of Cotton through CIB&RC recommended new chemical pesticides and their Combinations
• Path.3(k) Field evaluation (Rhizospheric fungi & chemicals etc.) for seed and soil-borne disease management

Path. 4 Crop loss estimation and distribution pattern of cotton diseases

• Path.4(e) Exp. 1a. Crop loss estimation due to CLCuD
• Path.4(e) Exp. 1b. Study on the distribution pattern of cotton leaf curl virus disease on local popular Bt hybrid at farmer’s fields

Significant Achievements: 2022-23

• Farmers’ field survey conducted in 802 villages (5-10 fields in each) of 35 districts in 10 states under all cotton growing zones of India and the major diseases observed during 2022-23 are:
  • North Zone: Cotton leaf curl virus disease (CLCuD), root rot during the mid-and late-season
  • Central & South Zone: Bacterial leaf blight (BLB), and grey mildew (GM) during mid-and lateseason
  • South Zone: Alternaria leaf blight (ALB), GM, boll rot, and rust during mid-and late-season
• Emerging/remerging diseases observed as moderate to severe are:
  • CLCuD in North Zone appeared 2-3 weeks early (21-23 SMW) in Punjab (41.8%), Haryana (25.1%) and Rajasthan (21.7%) and severity was 10-22% higher than in the previous year.
  • Grey mildew in Central and South Zone: 3.5 to 40.5% in Nanded, Akola, Buldana, Khandwa, Junagarh and 5-21.5% in Dharwad, Haveri, Guntur).
  • Tobacco streak virus in South Zone: traces to 30.0% in Warangal, Kurnool, Guntur and 0.5 to 17.5% in Coimbatore, Dindugal in Tamil Nadu.
  • Corynespora leaf spot in Central and South Zone: upto14.5% in Junagarh, Rajkot, Jamnagar and up to 29.5% in Guntur, Krishna, Prakasam districts of AP.
  • Alternaria leaf blight and boll rot in South Zone: 5 – 28% and 5- 16% in Dharwad, Haveri, Belagavi in Karnataka
• Disease progress in relation to weather parameters studied at on-station trials and the regression equations developed previously were compared/validated with the current season data and equations.
• Disease screening trials: 15 National (4) and Zonal trials (11) conducted under field conditions and promising disease-tolerant entries identified
  • North Zone: none of the entries was found resistant to CLCuD and root rot
  • Central Zone: Grey mildew-2 entry (GAM 288, JLA 1641) Alternaria-2 entry (PA 919, GBav 181) in IET-Ga NT, Bacterial leaf blight-5 entry (CCH 20452, CNH 19325, CNH 19480, 16301 DB, CNH 20449), Grey mildew 3 entry (CNH 19480, 16301 DB, CNH 20449) in PVT Gh-CC ZT, Grey mildew 2 entry (GAM 283, GAM 266) CVT-Ga,
  • South Zone: Corynespora leaf spot- 1 entry (DHCC 2002), PVT CC ZT, Corynespora leaf spot 1 entry (RAH 1083) CVT Gh ZT, GM-5 entry (CCB 26, CCB22-2, CCB22-1, SIMA B-8, CCB 6) CVT Gb ZT.
• Confirmation of disease resistance trials under field and artificial screening. After three years 19 entries were identified.
  • CLCuD: 3 entries (RS-2909, F-2687,RAH-1076), BLB: 2 entries (GSHH-15032, GSHH-15035) CoLS: 2 entries (DHCC-1801, DHCC-1902), rust: 3 (RAH-1083, CNH-19480, Suraj),grey mildew: 2 entries (SCS-1206, DB-14)and ALB – 2 entries (GJHV-584, CCB-29)
  • Multiple disease-resistant: BLB & ALB – 2 entries (GJHV 557, GISV-323), ALB& GM-2 entries (SVA-1118, DB-14), rust & CoLS- 1 entry (CNH 20-31)
• Multilocation field trials for disease management were conducted and the promising treatments were noted.
  • Among biopesticides, mineral paraffin oil and their combinations evaluated against seed & soilborne diseases, maximum seed germination, reduction in plant mortality and higher yield over control was observed with CICR T. asperellum (Rf-B/Th-11) as seed @5g/kg + soil treatment @2.5 kg/ha at sowing and foliar spray at 60 and 90 DAS @ 2 ml/L + mineral paraffin oil @0.75%.
  • Application of CICR Bacillus aryabhattai + Bacillus tequeilencis as seed treatment @10g/kg + soil application @ 2.5 kg/ha (30 & 60 DAS); and seed treatment Carboxin 37.5+ Thiram37.5%WS @ 0.2% and foliar application of Pyraclostrobin @ 0.1% recorded maximum reduction in ALB, BLB and GM at Surat, Akola
  • Application of CICR Pf-CICR as seed treatment @10g/kg + soil application @ 2.5 kg/ha (30 & 60 DAS) with FYM/compost was superior over other treatments for the management of ALB, BLB at Surat.
• Among the new IPM and new biomodules developed using first 2 spray of neem oil (300ppm), 1-2 spray of insecticides and 1-2 spray of CICR bioinsecticides (CICR Bb4511-Beauveria bassiana, CICR Ma1299 -Metarhizium anisopliae and CICR Cj102- Cordyceps javanica), reduction in whitefly nymphal, adult mortality and CLCuD was recorded over control. Mortality of nymphs and adults in new IPM modules ranged 34.9 to 47%, and 38.8 to 53.6% and in new Biomodules it was 34.3 to 41.3%, and 39 to 45.5%.
• Among the 11 CIB&RC recommended chemicals evaluated for the management of foliar diseases and boll rot, the top effective treatments (1-2 spray) over control were
  • Sooty mold (whitefly & aphid): 3 sprays of Propiconazole 25 EC @ 1 ml/L, copper oxychloride (COC) 50 WP @ 2.5 g/L, and Flonicamid 50 WP @0.6g/L Faridkot, Hisar & Tamil Nadu.
  • Fungal foliar spots- Kresoxim methyl @1 ml/L, Azoxystrobin + Difenoconazole @1 ml/L
  • ALB &CoLS- Fluxapyroxad + Pyraclostrobin@0.8ml/L, Azoxystrobin + Difenoconazole@1 ml/L
  • GM & Rust- Fluxapyroxad + Pyraclostrobin@0.8 ml/L, Metiram + Pyraclostrobin@.2g/L,
  • BLB &Boll rot- Fluxapyroxad + Pyraclostrobin@0.8 ml /L and Copper oxychloride, @2.5g/L
• Crop loss estimation studies were conducted at on-station trials : the average seed cotton yield reduction in mixed grades was ranged from 29.4 to 31.2%, in US51, RCH 773, NCS 9013I, and ACH177-2 hybrids. Reduction of SCY corresponding to CLCuD severity grades was 0=Nil, 1= 6.6, 2=19.5, 3=35, 4=50.9, 5=58.1, and 6= 69.2%
• Publications/ recommendations in POPs: 10 research papers & 7 AICRP technology/ recommendations were published in POPs of SAUs including, POPs of ANGRAU, TNAU, PAU, HAU, UAS Dharwad, NAU & Kamdhenu University, Junagarh.