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Biological management of collar, stem and root rot disease complex and white grubs using Trichoderma harzianum and Metarhizium anisopliae in groundnut

Pratibha Sharma: Sri Karan Narendra Agriculture University (SKNAU)

<div>The experimental study was conducted in two agroclimatic conditions of Rajasthan, zone IV B southern humid zone and III A semi-arid eastern zone in humid conditions for ecofriendly management of two major biotic stresses in groundnut crop caused by <em>Aspergillus </em>sp.,<em> Macrophomina phaseolina, Sclerotium rolfsii </em>and<em> Rhizoctonia solani</em> in the form of collar, stem and root rot disease complex along with attack by <em>Holotrichea</em> <em>consanguinea</em> (white grubs). Under <em>in vitro</em> studies, the combined application of <em>Trichoderma harzianum</em> (4.3 x 10<sup>6 </sup>cfu/ml) and <em>Metarhizium anisopliae</em> (2.3 x 10 <sup>6</sup> conidia/ml) reduced disease incidence in a range of 40-50% and suppressed the egg hatching and killed 1<sup>st</sup> and 2<sup>nd</sup> instar larvae of white grubs from 78% to 100%. Soil application with <em>T. harzianum</em> and <em>M. anisopliae</em> enriched farm yard manure (1:20) + seed treatment with <em>T. harzianum</em> + drenching twice with <em>T. harzianum</em> was found very effective to reduce the disease complex and two times drenching with <em>M. anisopliae</em> significantly reduced 68 % white grub population as compared with control. Another two treatments as fungicidal check of soil application by neem cake and seed treatment with Thiophanate Methyl 450 g/L + Pyraclostrobin 50 g/L FS and Carbendazim 12% + Mancozeb 63% WP were found more effective than application of BCAs to reduce disease incidence and the Imidacloprid 17.8 SL was used as chemical check against white grub which was found at par with application of <em>M. anisopliae</em> but also reduced infestation of white grubs to increase pod yield by 33.6%.</div>