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A survey was conducted in the sesame fields of Karnataka, India during April–June 2010 (summer) and in Telangana State, Maharashtra and Karnataka during July–September 2010 (Kharif). In summer, disease incidence of 18.57–31.6% was recorded, whereas, in Kharif, incidence of 44.66–68%, 13–47.14% and 32.14% was recorded in Telangana State, Karnataka and Maharashtra respectively. Three symptomatic and two non-symptomatic samples from summer crop and sixteen symptomatic and two non symptomatic samples from Kharifseason fields were collected. The disease etiology was confirmed using nested polymerase chain reaction (PCR) with phytoplasma universal primers P1/P7 followed by R16F2n/R16R2 which amplified ~ 1.8 and ~ 1.25 kb in the 16SrDNA gene. The BLAST and phylogenetic analysis of 16S rDNA gene further revealed that phytoplasma associated with phyllody disease in both the season were belonged to peanut witches’ broom group (16SrII). Further, iPhyClassifier analysis of 1.25 kb product of 16S rDNA sequence classified the isolates into 16SrII-A and 16SrII-D subgroups. All summer crop isolates were classified under 16SrII-D subgroup whereas; Kharifseason isolates were grouped under 16SrII-A and 16SrII-D group. Phylogenetic analysis revealed the distinct subgroup-wise as well as season-wise clustering pattern where subgroup 16SrII-A and 16SrII-D clustered separately and summer and Kharifseason isolates clustered separately. Our study reports that the sesame phyllody disease in Kharifseason is caused by the taxonomically distinct strains (16SrII-A and 16SrII-D) whereas, in the summer crop, it is associated with 16SrII-D subgroup alone.

Forty Trichodermaisolates were collected from North-eastern dry zone of Karnataka to assess abiotic and biotic stress tolerance and chickpea Fusarium wilt management abilities. Among the isolates collected, Trichoderma asperellumand Hypocrea lixiispecies were predominantly distributed in the study area. In-vitro experiments showed that isolate T-46, T-43, T-17, T-13, T-36 and T-45 are effective in antagonistic and volatile compounds (VCs) production against chickpea pathogens. The NaCl salt range from 400 to 600 mM and temperature from 20 to 35 °C was optimum for normal growth and sporulation of Trichodermaisolates. The salt concentration above 600 mM NaCl and temperature < 15 and > 37 °C was found detrimental to Trichodermamycelial growth, conidia and chlamydospores productions. Based on the abiotic and biotic stress tolerance five isolates (T-10, T-17, T-25, T-46, T-50) were selected for field experiment to manage chickpea Fusarium wilt. Treatment with T-17 and T-46 showed highest wilt inhibition over control in Annigeri cultivar in the sick soil condition. Under glasshouse conditions isolate T-46 exhibited delayed onset of Fusarium wilt incidence in JG 62 cultivar. The lowest AUDPC and relative AUDPC was observed in T-46 (70.50 ± 1.00 and 2.43 ± 0.03) and carbendazim (73.44 ± 4.12 and 2.53 ± 0.14) treated treatments. This finding provides insights on indigenous Trichodermaisolates tolerant to abiotic and biotic stress and can be used to alleviate chickpea Fusarium wilt in farmer fields.