Occurrence status and management of alternaria blight (Alternaria species) of linseed (Linum usitatissimum)

Abstract

A field experiment was conducted during 1995-96 to 2002-2003 to study the status of alternaria blight, caused by Alternaria lini Dey and Alternaria linicola Groves & Skolko, of linseed (Linum usitatissimum L.) and to work out an integrated schedule for its management during 2001-2002 and 2002-2003. Foliar blight, initiated between 18 November and 5 January, attained highest intensity (55.80-85.85%) between 15 February and 2 March, taking 50-87 days. 'Sheela' linseed sown on 7 November with seed treated with thiophanate methyl @ 2 g/kg seed followed by a foliar spraying of mancozeb 75 WP (0.25%) showed least disease intensity (17.54%) and gave highest seed yield (2094.6 kg/ha). Though net return (Rs 9348/ha) for this treatment was highest, seed treatment alone for 16 October-sown 'Sheela' with benefit: cost ratio of 72.70 was found to be most cost-effective followed by 7 November-sown 'Chambal' (62.23). Highest avoidable yield loss of 41.18% was noted in 16 October sown 'Chambal' under seed treatment followed by foliar spraying.