Evaluation of Fungicides, Bioagents and Plant Extracts against Exserohilum turcicum Causing Turcicum Leaf Blight of Maize

Abstract

Twelve fungicides including systemic and non-systemic, five bioagents and eight plant extracts were evaluated in vitro against Exserohilum turcicum, the causal agent of Turcicum leaf blight of maize. All the test fungicides, bioagents and plant extracts showed fungistatic action and significantly inhibited mycelial growth of the test pathogen over untreated control. Among systemic fungicides, propiconazole was found best in inhibiting the mycelial growth of E. turcicum (96.51% mean inhibition), mancozeb among non- systemic fungicides was found best (95.23% mean inhibition), Trichoderma harzianum among bioagents was found best (76.38% inhibition) and among plant extracts, neem oil inhibited maximum mycelial growth of E. turcicum (62.33%). The best performing in vitro fungicides, bioagents and botanicals when tested in field showed that two foliar sprays with non-systemic fungicide, mancozeb 75 WP @ 0.25 per cent reduced the diseased intensity from 20.45 per cent in control to 5.69 per cent and increased the grain yield from 45.20 q/ ha in control to 52.50 q/ha; two foliar sprays with systemic fungicide, propiconazole 25 EC @ 0.1 per cent reduced the diseased intensity to 6.11 per cent and increased the grain yield to 52.25 q/ha; two foliar sprays with plant extract, neem oil @ 5 per cent reduced the diseased intensity to 10.90 per cent and increased the grain yield to 49.90 q/ha while seed treatment with bioagent, Trichoderma harzianum 2x108 cfu/g @ 0.4 per cent followed by two foliar sprays with mancozeb 75 WP @ 0.25 per cent could further reduce the disease intensity to 5.40 per cent and increase grain yield to 53.60 q/ha.