A study was conducted to determine the efficacy of esterified glucomannan in counteracting the toxic effects of mycotoxins in naturally contaminated diet (aflatoxin 168 ppb, ochratoxin 8.4 ppb, zearalenone 54 ppb, and T-2 toxin 32 ppb) fed to commercial broilers. One-day-old broiler chicks were randomly assigned to one of the four dietary treatments with five replicates of 14 chicks each. Four dietary treatments were 1) control; 2) esterified glucomannan, an adsorbent, tested at 0.05% of diet; 3) naturally contaminated diet; and 4) esterified glucomannan (0.05%) plus naturally contaminated diet. Body weight, feed consumption, feed efficiency, hematology, and serum biochemical and enzyme activities were evaluated. Compared with the control, the naturally contaminated diet significantly decreased body weight and feed consumption and resulted in poor feed efficiency. Esterified glucomannan effectively alleviated the growth depression caused by the naturally contaminated diet. Increased relative weights of liver and gizzard were observed in chicks fed the naturally contaminated diet. Further, feeding a naturally contaminated diet was associated with significant decreases in urea nitrogen and hematocrit values along with altered gamma-glutamyl transferase activity; however, urea nitrogen concentration was improved with addition of esterified glucomannan. These findings suggest that addition of dietary esterified glucomannan is effective in counteracting the toxic effects of naturally contaminated feed with mycotoxins.

No abstract

Rice blast caused by Pyricularia grisea (Cooke) Sacc. became one of the most important disease in rice growing areas of Telangana State because of its wide distribution and destructiveness under favourable conditions. However, sometimes resistant varieties may become ineffective due to evolutionary changes in the pathogen population. Keeping in view the importance of disease, studies were conducted on cultural and morphological variability of P. grisea isolates. Blast infected samples were collected from different locations of Telangana State were studied for radial growth, colony color, growth pattern, texture of colony, sectoring, zonation and wrinkles formation, dry mycelial weight, time of sporulation and sporulation index. The highest mean radial mycelial growth of the fungus was recorded on OMA (81.7 mm) followed by PDA (77.8 mm) and least mean radial mycelial growth of the P. grisea isolates were recorded on HLEA medium (72.5 mm). Colony colour of twelve P. grisea isolates were differed from greyish white to greyish black on three solid media tested. All the isolates were circular form and varied with respect to mycelium elevation and texture. Significant differences were also observed among the isolates with the formation of sector, zonation and wrinkles. Among the three different liquid media tested, highest mean mycelial dry weight of the P.grisea isolates was recorded on PDB (225 mg) followed by OMB (214 mg) and least mean mycelial dry weight on HLEB(164 mg).Time taken for sporulation of P. grisea isolates on OMA medium was 7.9 days followed by HLEA medium for 8 days and PDA medium for 8.2 days. Sporulation index of twelve P.grisea isolates were varied from poor to excellent on rating scale of 1 to 4 on three solid media tested. Conidia of the isolates were produced in clusters on long septate, slender conidiophores. The mean conidial size ranged from 18.9 μm to 28.2 μm in length and 6.1 μm to 9.3 μm in width among twelve P. grisea isolates. The shape of conidia in all the isolates was pyriform and hyaline to pale olive, 2 septate and 3 celled. Spore germination percentage was high in Pg1 isolate (91.6 %) and least in Pg6 isolate (28.3 %). K e y w o r d sRice blast, Pyricularia grisea, Rice [Oryza sativa]

Biocontrol agents are beneficial for plant and soil health and are effective in controlling many plant diseases. These biocontrol agents in combination with fungicides at reduced doses can be more effective than using alone. Keeping this in view, an in vitro study was carried out to test the compatibility of commonly used fungicides viz., captan 50 WP, thiram 75% DS, tebuconazole 5.36% FS, carboxin 37.5% + thiram 37.5% DS, prochloraz 24.4% + tebuconazole 12.1% w/w EW and thiophanate methyl 450 g/l + pyraclostrobin 50 g/l with two fungal (Trichoderma asperellum and T.viride) and three bacterial biocontrol agents (Bacillus subtilis S4KB5, B. subtilis S8KB2 and B. subtilis B3). All the five fungicides were found to be compatible with all the biocontrol agents at 100ppm and 250ppm. All the fungicides except thiram, showed complete inhibition of T. asperellum at 1500ppm and 2000ppm and with T. viride, 100 per cent inhibition is shown by all the fungicides at 1500ppm and 2000ppm except carboxin + thiram. With biocontrol isolates, B. subtilis S4KB5, B. subtilis S8KB2 and B. subtilis B3, highest inhibition zone were recorded by prochloraz + tebuconazole (2000ppm), tebuconazole (2000ppm) and thiophanate methyl + pyraclostrobin (2000ppm). Present findings suggest that compatible fungicides can be used with biocontrol agents in an integrated disease management practices for the control of seed and soil borne pathogens.